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Fsdb

NAME

Fsdb - a flat-text database for shell scripting

SYNOPSIS

Fsdb, the flatfile streaming database is package of commands for manipulating flat-ASCII databases from shell scripts. Fsdb is useful to process medium amounts of data (with very little data you’d do it by hand, with megabytes you might want a real database). Fsdb was known as as Jdb from 1991 to Oct. 2008.

Fsdb is very good at doing things like:

extracting measurements from experimental output

examining data to address different hypotheses

joining data from different experiments

eliminating/detecting outliers

computing statistics on data (mean, confidence intervals, correlations, histograms)

reformatting data for graphing programs

Fsdb is built around the idea of a flat text file as a database. Fsdb files (by convention, with the extension .fsdb), have a header documenting the schema (what the columns mean), and then each line represents a database record (or row).

For example:

#fsdb experiment duration
ufs_mab_sys 37.2
ufs_mab_sys 37.3
ufs_rcp_real 264.5
ufs_rcp_real 277.9

Is a simple file with four experiments (the rows), each with a description, size parameter, and run time in the first, second, and third columns.

Rather than hand-code scripts to do each special case, Fsdb provides higher-level functions. Although it’s often easy throw together a custom script to do any single task, I believe that there are several advantages to using Fsdb:

these programs provide a higher level interface than plain Perl, so

**

Fewer lines of simpler code:

dbrow '_experiment eq "ufs_mab_sys"' | dbcolstats duration

Picks out just one type of experiment and computes statistics on it, rather than:

while (<>) { split; $sum+=$F[1]; $ss+=$F[1]**2; $n++; }
$mean = $sum / $n; $std_dev = ...

in dozens of places.

the library uses names for columns, so

**

No more $F[1], use "_duration".

**

New or different order columns? No changes to your scripts!

Thus if your experiment gets more complicated with a size parameter, so your log changes to:

#fsdb experiment size duration
ufs_mab_sys 1024 37.2
ufs_mab_sys 1024 37.3
ufs_rcp_real 1024 264.5
ufs_rcp_real 1024 277.9
ufs_mab_sys 2048 45.3
ufs_mab_sys 2048 44.2

Then the previous scripts still work, even though duration is now the third column, not the second.

A series of actions are self-documenting (the provenance of processsing done to produce each output is recorded in comments).

**

No more wondering what hacks were used to compute the final data, just look at the comments at the end of the output.

For example, the commands

dbrow '_experiment eq "ufs_mab_sys"' | dbcolstats duration

add to the end of the output the lines
# | dbrow _experiment eq "ufs_mab_sys"
# | dbcolstats duration

The library is mature, supporting large datasets (more than 100GB), parallelism, corner cases, error handling, backed by an automated test suite.

**

No more puzzling about bad output because your custom script skimped on error checking.

**

No more memory thrashing when you try to sort ten million records.

**

Makes use of multiple cores in your computer when it can, because each pipeline component runs in parallel, and because key tools (dbsort, dbmapreduce) run in parlallel when possible.

Fsdb-2.x supports Perl scripting (in addition to shell scripting), with libraries to do Fsdb input and output, and easy support for pipelines. The shell script

dbcol name test1 | dbroweval '_test1 += 5;'

can be written in perl as:

dbpipeline(dbcol(qw(name test1)), dbroweval('_test1 += 5;'));

(The disadvantage is that you need to learn what functions Fsdb provides.)

Fsdb is built on flat-ASCII databases. By storing data in simple text files and processing it with pipelines it is easy to experiment (in the shell) and look at the output. To the best of my knowledge, the original implementation of this idea was "/rdb", a commercial product described in the book UNIX relational database management: application development in the UNIX environment by Rod Manis, Evan Schaffer, and Robert Jorgensen (1988 by Prentice Hall, and also at the web page <http://www.rdb.com/>). Fsdb is an incompatible re-implementation of their idea without any accelerated indexing or forms support. (But it’s free, and probably has better statistics!).

Fsdb-2.x will exploit multiple processors or cores, and provides Perl-level support for input, output, and threaded-pipelines. (As of Fsdb-2.44 it no longer uses Perl threading, just processes, since they are faster.)

Installation instructions follow at the end of this document. Fsdb-2.x requires Perl 5.8 to run. All commands have manual pages and provide usage with the "--help" option. All commands are backed by an automated test suite.

The most recent version of Fsdb is available on the web at <http://www.isi.edu/~johnh/SOFTWARE/FSDB/index.html>.

WHAT’S NEW

3.1, 2022-11-22 A post-3.0 cleanup release with minor fixes.
ENHANCEMENT

Type specifications in a few more programs that I missed: dbrowuniq, dbcolpercentile.

ENHANCEMENT

Minor documentation improvements.

README CONTENTS

executive summary
what’s new
README CONTENTS

installation
basic data format
basic data manipulation
list of commands
another example
a gradebook example
a password example
history
related work
release notes
copyright
comments

INSTALLATION

Fsdb now uses the standard Perl build and installation from ExtUtil::MakeMaker(3), so the quick answer to installation is to type:

perl Makefile.PL
make
make test
make install

Or, if you want to install it somewhere else, change the first line to

perl Makefile.PL PREFIX=$HOME

and it will go in your home directory’s bin, etc. (See ExtUtil::MakeMaker(3) for more details.)

Fsdb requires perl 5.8 or later.

A test-suite is available, run it with

make test

In the past, the ports existed for FreeBSD and MacOS. If someone running one of those OSes wants to contribute a new port, please let me know.

BASIC DATA FORMAT

These programs are based on the idea storing data in simple ASCII files. A database is a file with one header line and then data or comment lines. For example:

#fsdb account passwd uid gid fullname homedir shell
johnh * 2274 134 John_Heidemann /home/johnh /bin/bash
greg * 2275 134 Greg_Johnson /home/greg /bin/bash
root * 0 0 Root /root /bin/bash
# this is a simple database

The header line must be first and begins with "#fsdb". There are rows (records) and columns (fields), just like in a normal database. Comment lines begin with "#". Column names are any string not containing spaces or single quote (although it is prudent to keep them alphanumeric with underscore).

Columns can optionally include type anntations by following name with :t where t is some type. (Types are not used in Perl, but are relevant in Python and Go Fsdb bindings.) Types use a subset of perl pack specifiers: c, s, l, q are signed 8, 16, 32, and 64-bit integers, f is a float, d is double float, a is utf-8 string, and &gt; and &lt; can force big or little endianness.

By default, columns are delimited by whitespace. With this default configuration, the contents of a field cannot contain whitespace. However, this limitation can be relaxed by changing the field separator as described below.

The big advantage of simple flat-text databases is that it is usually easy to massage data into this format, and it’s reasonably easy to take data out of this format into other (text-based) programs, like gnuplot, jgraph, and LaTeX. Think Unix. Think pipes. (Or even output to Excel and HTML if you prefer.)

Since no-whitespace in columns was a problem for some applications, there’s an option which relaxes this rule. You can specify the field separator in the table header with "-F x" where "x" is a code for the new field separator. A full list of codes is at dbfilealter(1), but two common special values are "-F t" which is a separator of a single tab character, and "-F S", a separator of two spaces. Both allowing (single) spaces in fields. An example:

#fsdb -F S account passwd uid gid fullname homedir shell
johnh * 2274 134 John Heidemann /home/johnh /bin/bash
greg * 2275 134 Greg Johnson /home/greg /bin/bash
root * 0 0 Root /root /bin/bash
# this is a simple database

See dbfilealter(1) for more details. Regardless of what the column separator is for the body of the data, it’s always whitespace in the header.

There’s also a third format: a "list". Because it’s often hard to see what’s columns past the first two, in list format each "column" is on a separate line. The programs dblistize and dbcolize convert to and from this format, and all programs work with either formats. The command

dbfilealter -R C < DATA/passwd.fsdb

outputs:

#fsdb -R C account passwd uid gid fullname homedir shell
account: johnh
passwd: *
uid: 2274
gid: 134
fullname: John_Heidemann
homedir: /home/johnh
shell: /bin/bash
account: greg
passwd: *
uid: 2275
gid: 134
fullname: Greg_Johnson
homedir: /home/greg
shell: /bin/bash
account: root
passwd: *
uid: 0
gid: 0
fullname: Root
homedir: /root
shell: /bin/bash
# this is a simple database
# | dblistize

See dbfilealter(1) for more details.

BASIC DATA MANIPULATION

A number of programs exist to manipulate databases. Complex functions can be made by stringing together commands with shell pipelines. For example, to print the home directories of everyone with ’’john’’ in their names, you would do:

cat DATA/passwd | dbrow '_fullname =~ /John/' | dbcol homedir

The output might be:

#fsdb homedir
/home/johnh
/home/greg
# this is a simple database
# | dbrow _fullname =~ /John/
# | dbcol homedir

(Notice that comments are appended to the output listing each command, providing an automatic audit log.)

In addition to typical database functions (select, join, etc.) there are also a number of statistical functions.

The real power of Fsdb is that one can apply arbitrary code to rows to do powerful things.

cat DATA/passwd | dbroweval '_fullname =~ s/(\w+)_(\w+)/$2,_$1/'

converts "John_Heidemann" into "Heidemann,_John". Not too much more work could split fullname into firstname and lastname fields.

(Or:

cat DATA/passwd | dbcolcreate sort | dbroweval -b 'use Fsdb::Support'
'_sort = _fullname; _sort =~ s/_/ /g; _sort = fullname_to_sort(_sort);'

TALKING ABOUT COLUMNS

An advantage of Fsdb is that you can talk about columns by name (symbolically) rather than simply by their positions. So in the above example, "dbcol homedir" pulled out the home directory column, and "dbrow '_fullname =~ /John/'" matched against column fullname.

In general, you can use the name of the column listed on the "#fsdb" line to identify it in most programs, and _name to identify it in code.

Some alternatives for flexibility:

Numeric values identify columns positionally, numbering from 0. So 0 or _0 is the first column, 1 is the second, etc.

In code, _last_columnname gets the value from columname’s previous row.

See dbroweval(1) for more details about writing code.

LIST OF COMMANDS

Enough said. I’ll summarize the commands, and then you can experiment. For a detailed description of each command, see a summary by running it with the argument "--help" (or "-?" if you prefer.) Full manual pages can be found by running the command with the argument "--man", or running the Unix command "man dbcol" or whatever program you want.

TABLE CREATION
dbcolcreate

add columns to a database

dbcoldefine

set the column headings for a non-Fsdb file

TABLE MANIPULATION
dbcol

select columns from a table

dbrow

select rows from a table

dbsort

sort rows based on a set of columns

dbjoin

compute the natural join of two tables

dbcolrename

rename a column

dbcolmerge

merge two columns into one

dbcolsplittocols

split one column into two or more columns

dbcolsplittorows

split one column into multiple rows

dbfilepivot

"pivots" a file, converting multiple rows corresponding to the same entity into a single row with multiple columns.

dbfilevalidate

check that db file doesn’t have some common errors

COMPUTATION AND STATISTICS
dbcolstats

compute statistics over a column (mean,etc.,optionally median)

dbmultistats

group rows by some key value, then compute stats (mean, etc.) over each group (equivalent to dbmapreduce with dbcolstats as the reducer)

dbmapreduce

group rows (map) and then apply an arbitrary function to each group (reduce)

dbrvstatdiff

compare two samples distributions (mean/conf interval/T-test)

dbcolmovingstats

computing moving statistics over a column of data

dbcolstatscores

compute Z-scores and T-scores over one column of data

dbcolpercentile

compute the rank or percentile of a column

dbcolhisto

compute histograms over a column of data

dbcolscorrelate

compute the coefficient of correlation over several columns

dbcolsregression

compute linear regression and correlation for two columns

dbrowaccumulate

compute a running sum over a column of data

dbrowcount

count the number of rows (a subset of dbstats)

dbrowdiff

compute differences between a columns in each row of a table

dbrowenumerate

number each row

dbroweval

run arbitrary Perl code on each row

dbrowuniq

count/eliminate identical rows (like Unix uniq(1))

dbfilediff

compare fields on rows of a file (something like Unix diff(1))

OUTPUT CONTROL
dbcolneaten

pretty-print columns

dbfilealter

convert between column or list format, or change the column separator

dbfilestripcomments

remove comments from a table

dbformmail

generate a script that sends form mail based on each row

CONVERSIONS
(These programs convert data into fsdb. See their web pages for details.)
cgi_to_db

<http://stein.cshl.org/boulder/>

combined_log_format_to_db

<http://httpd.apache.org/docs/2.0/logs.html>

html_table_to_db

HTML tables to fsdb (assuming they’re reasonably formatted).

kitrace_to_db

<http://ficus-www.cs.ucla.edu/ficus-members/geoff/kitrace.html>

ns_to_db

<http://mash-www.cs.berkeley.edu/ns/>

sqlselect_to_db

the output of SQL SELECT tables to db

tabdelim_to_db

spreadsheet tab-delimited files to db

tcpdump_to_db

(see man tcpdump(8) on any reasonable system)

xml_to_db

XML input to fsdb, assuming they’re very regular

(And out of fsdb:)
db_to_csv

Comma-separated-value format from fsdb.

db_to_html_table

simple conversion of Fsdb to html tables

STANDARD OPTIONS
Many programs have common options:
-?
or --help

Show basic usage.

-N on --new-name

When a command creates a new column like dbrowaccumulate’s "accum", this option lets one override the default name of that new column.

-T TmpDir

where to put tmp files. Also uses environment variable TMPDIR, if -T is not specified. Default is /tmp.

Show basic usage.

-c FRACTION or --confidence FRACTION

Specify confidence interval FRACTION (dbcolstats, dbmultistats, etc.)

-C S or "--element-separator S"

Specify column separator S (dbcolsplittocols, dbcolmerge).

-d or --debug

Enable debugging (may be repeated for greater effect in some cases).

-a or --include-non-numeric

Compute stats over all data (treating non-numbers as zeros). (By default, things that can’t be treated as numbers are ignored for stats purposes)

-S or --pre-sorted

Assume the data is pre-sorted. May be repeated to disable verification (saving a small amount of work).

-e E or --empty E

give value E as the value for empty (null) records

-i I or --input I

Input data from file I.

-o O or --output O

Write data out to file O.

--header H

Use H as the full Fsdb header, rather than reading a header from then input. This option is particularly useful when using Fsdb under Hadoop, where split files don’t have heades.

--nolog.

Skip logging the program in a trailing comment.

When giving Perl code (in dbrow and dbroweval) column names can be embedded if preceded by underscores. Look at dbrow(1) or dbroweval(1) for examples.)

Most programs run in constant memory and use temporary files if necessary. Exceptions are dbcolneaten, dbcolpercentile, dbmapreduce, dbmultistats, dbrowsplituniq.

STANDARD SORTING OPTIONS
A number of programs do sorting, or depend on defining an ordering of rows. Such programs use these standard sorting options:
-r
or --descending

sort in reverse order (high to low)

-R or --ascending

sort in normal order (low to high)

-t or --type-inferred-sorting

sort fields by type (numeric or leicographic), automatically

-n or --numeric

sort numerically

-N or --lexical

sort lexicographically

ANOTHER EXAMPLE

Take the raw data in "DATA/http_bandwidth", put a header on it ("dbcoldefine size bw"), took statistics of each category ("dbmultistats -k size bw"), pick out the relevant fields ("dbcol size mean stddev pct_rsd"), and you get:

#fsdb size mean stddev pct_rsd
1024 1.4962e+06 2.8497e+05 19.047
10240 5.0286e+06 6.0103e+05 11.952
102400 4.9216e+06 3.0939e+05 6.2863
# | dbcoldefine size bw
# | /home/johnh/BIN/DB/dbmultistats -k size bw
# | /home/johnh/BIN/DB/dbcol size mean stddev pct_rsd

(The whole command was:

cat DATA/http_bandwidth |
dbcoldefine size |
dbmultistats -k size bw |
dbcol size mean stddev pct_rsd

all on one line.)

Then post-process them to get rid of the exponential notation by adding this to the end of the pipeline:

dbroweval '_mean = sprintf("%8.0f", _mean); _stddev = sprintf("%8.0f", _stddev);'

(Actually, this step is no longer required since dbcolstats now uses a different default format.)

giving:

#fsdb size mean stddev pct_rsd
1024 1496200 284970 19.047
10240 5028600 601030 11.952
102400 4921600 309390 6.2863
# | dbcoldefine size bw
# | dbmultistats -k size bw
# | dbcol size mean stddev pct_rsd
# | dbroweval { _mean = sprintf("%8.0f", _mean); _stddev = sprintf("%8.0f", _stddev); }

In a few lines, raw data is transformed to processed output.

Suppose you expect there is an odd distribution of results of one datapoint. Fsdb can easily produce a CDF (cumulative distribution function) of the data, suitable for graphing:

cat DB/DATA/http_bandwidth | \
dbcoldefine size bw | \
dbrow '_size == 102400' | \
dbcol bw | \
dbsort -n bw | \
dbrowenumerate | \
dbcolpercentile count | \
dbcol bw percentile | \
xgraph

The steps, roughly: 1. get the raw input data and turn it into fsdb format, 2. pick out just the relevant column (for efficiency) and sort it, 3. for each data point, assign a CDF percentage to it, 4. pick out the two columns to graph and show them

A GRADEBOOK EXAMPLE

The first commercial program I wrote was a gradebook, so here’s how to do it with Fsdb.

Format your data like DATA/grades.

#fsdb name email id test1
a a AT ucla DOT example DOT edu 1 80
b b AT usc DOT example DOT edu 2 70
c c AT isi DOT example DOT edu 3 65
d d AT lmu DOT example DOT edu 4 90
e e AT caltech DOT example DOT edu 5 70
f f AT oxy DOT example DOT edu 6 90

Or if your students have spaces in their names, use "-F S" and two spaces to separate each column:

#fsdb -F S name email id test1
alfred aho a AT ucla DOT example DOT edu 1 80
butler lampson b AT usc DOT example DOT edu 2 70
david clark c AT isi DOT example DOT edu 3 65
constantine drovolis d AT lmu DOT example DOT edu 4 90
debrorah estrin e AT caltech DOT example DOT edu 5 70
sally floyd f AT oxy DOT example DOT edu 6 90

To compute statistics on an exam, do

cat DATA/grades | dbstats test1 |dblistize

giving

#fsdb -R C ...
mean: 77.5
stddev: 10.84
pct_rsd: 13.987
conf_range: 11.377
conf_low: 66.123
conf_high: 88.877
conf_pct: 0.95
sum: 465
sum_squared: 36625
min: 65
max: 90
n: 6
...

To do a histogram:

cat DATA/grades | dbcolhisto -n 5 -g test1

giving

#fsdb low histogram
65 *
70 **
75
80 *
85
90 **
# | /home/johnh/BIN/DB/dbhistogram -n 5 -g test1

Now you want to send out grades to the students by e-mail. Create a form-letter (in the file test1.txt):

To: _email (_name)
From: J. Random Professor <jrp AT usc DOT example DOT edu>
Subject: test1 scores
_name, your score on test1 was _test1.
86+ A
75-85 B
70-74 C
0-69 F

Generate the shell script that will send the mail out:

cat DATA/grades | dbformmail test1.txt > test1.sh

And run it:

sh <test1.sh

The last two steps can be combined:

cat DATA/grades | dbformmail test1.txt | sh

but I like to keep a copy of exactly what I send.

At the end of the semester you’ll want to compute grade totals and assign letter grades. Both fall out of dbroweval. For example, to compute weighted total grades with a 40% midterm/60% final where the midterm is 84 possible points and the final 100:

dbcol -rv total |
dbcolcreate total - |
dbroweval '
_total = .40 * _midterm/84.0 + .60 * _final/100.0;
_total = sprintf("%4.2f", _total);
if (_final eq "-" || ( _name =~ /^_/)) { _total = "-"; };' |
dbcolneaten

If you got the data originally from a spreadsheet, save it in "tab-delimited" format and convert it with tabdelim_to_db (run tabdelim_to_db -? for examples).

A PASSWORD EXAMPLE

To convert the Unix password file to db:

cat /etc/passwd | sed 's/:/ /g'| \
dbcoldefine -F S login password uid gid gecos home shell \
>passwd.fsdb

To convert the group file

cat /etc/group | sed 's/:/ /g' | \
dbcoldefine -F S group password gid members \
>group.fsdb

To show the names of the groups that div7-members are in (assuming DIV7 is in the gecos field):

cat passwd.fsdb | dbrow '_gecos =~ /DIV7/' | dbcol login gid | \
dbjoin -i - -i group.fsdb gid | dbcol login group

SHORT EXAMPLES

Which Fsdb programs are the most complicated (based on number of test cases)?

ls TEST/*.cmd | \
dbcoldefine test | \
dbroweval '_test =~ s@^TEST/([^_]+).*$@$1@' | \
dbrowuniq -c | \
dbsort -nr count | \
dbcolneaten

(Answer: dbmapreduce, then dbcolstats, dbfilealter and dbjoin.)

Stats on an exam (in $FILE, where $COLUMN is the name of the exam)?

cat $FILE | dbcolstats -q 4 $COLUMN <$FILE | dblistize | dbstripcomments
cat $FILE | dbcolhisto -g -n 20 $COLUMN | dbcolneaten | dbstripcomments

Merging a the hw1 column from file hw1.fsdb into grades.fsdb assuming there’s a common student id in column "id":

dbcol id hw1 <hw1.fsdb >t.fsdb
dbjoin -a -e - grades.fsdb t.fsdb id | \
dbsort name | \
dbcolneaten >new_grades.fsdb

Merging two fsdb files with the same rows:

cat file1.fsdb file2.fsdb >output.fsdb

or if you want to clean things up a bit

cat file1.fsdb file2.fsdb | dbstripextraheaders >output.fsdb

or if you want to know where the data came from

for i in 1 2
do
dbcolcreate source $i < file$i.fsdb
done >output.fsdb

(assumes you’re using a Bourne-shell compatible shell, not csh).

WARNINGS

As with any tool, one should (which means must) understand the limits of the tool.

All Fsdb tools should run in constant memory. In some cases (such as dbcolstats with quartiles, where the whole input must be re-read), programs will spool data to disk if necessary.

Most tools buffer one or a few lines of data, so memory will scale with the size of each line. (So lines with many columns, or when columns have lots data, may cause large memory consumption.)

All Fsdb tools should run in constant or at worst "n log n" time.

All Fsdb tools use normal Perl math routines for computation. Although I make every attempt to choose numerically stable algorithms (although I also welcome feedback and suggestions for improvement), normal rounding due to computer floating point approximations can result in inaccuracies when data spans a large range of precision. (See for example the dbcolstats_extrema test cases.)

Any requirements and limitations of each Fsdb tool is documented on its manual page.

If any Fsdb program violates these assumptions, that is a bug that should be documented on the tool’s manual page or ideally fixed.

Fsdb does depend on Perl’s correctness, and Perl (and Fsdb) have some bugs. Fsdb should work on perl from version 5.10 onward.

HISTORY

There have been four major versions of Fsdb: fsdb-0.x was begun in 1991 for my personal use. Fsdb 1.0 is a complete re-write of the pre-1995 versions, and was distributed from 1995 to 2007. Fsdb 2.0 is a significant re-write of the 1.x versions to systematically use a library and threads (although threads were abandoned in 2.44). Fsdb 3.0 in 2022 adds type specifiers to the schema, mostly to support use in languages with stronger typing (like Python, Go, and C).

Fsdb (in its various forms) has been used extensively by its author since 1991. Since 1995 it’s been used by two other researchers at UCLA and several at ISI. In February 1998 it was announced to the Internet. Since then it has found a few users, some outside where I work.

Major changes:
1.0 1997-07-22: first public release.
2.0 2008-01-25: rewrite to use a common library, and starting to use
threads.
2.12 2008-10-16: completion of the rewrite, and first RPM package.
2.44 2013-10-02: abandoning threads for improved performance
3.0 2022-04-04: adding type specifiers to the schema

Fsdb 2.0 Rationale
I’ve thought about fsdb-2.0 for many years, but it was started in earnest in 2007. Fsdb-2.0 has the following goals:
in-one-process processing

While fsdb is great on the Unix command line as a pipeline between programs, it should also be possible to set it up to run in a single process. And if it does so, it should be able to avoid serializing and deserializing (converting to and from text) data between each module. (Accomplished in fsdb-2.0: see dbpipeline, although still needs tuning.)

clean IO API

Fsdb’s roots go back to perl4 and 1991, so the fsdb-1.x library is very, very crufty. More than just being ugly (but it was that too), this made things reading from one format file and writing to another the application’s job, when it should be the library’s. (Accomplished in fsdb-1.15 and improved in 2.0: see Fsdb::IO.)

normalized module APIs

Because fsdb modules were added as needed over 10 years, sometimes the module APIs became inconsistent. (For example, the 1.x "dbcolcreate" required an empty value following the name of the new column, but other programs specify empty values with the "-e" argument.) We should smooth over these inconsistencies. (Accomplished as each module was ported in 2.0 through 2.7.)

everyone handles all input formats

Given a clean IO API, the distinction between "colized" and "listized" fsdb files should go away. Any program should be able to read and write files in any format. (Accomplished in fsdb-2.1.)

Fsdb-2.0 preserves backwards compatibility where possible, but breaks it where necessary to accomplish the above goals. In August 2008, Fsdb-2.7 was declared preferred over the 1.x versions. Benchmarking in 2013 showed that threading performed much worse than just using pipes, so Fsdb-2.44 uses threading "style", but implemented with processes (via my "Freds" library).

Contributors
Fsdb includes code ported from Geoff Kuenning ("Fsdb::Support::TDistribution").

Fsdb contributors: Ashvin Goel goel AT cse DOT oge DOT edu, Geoff Kuenning geoff AT fmg DOT cs DOT ucla DOT edu, Vikram Visweswariah visweswa AT isi DOT edu, Kannan Varadahan kannan AT isi DOT edu, Lars Eggert larse AT isi DOT edu, Arkadi Gelfond arkadig AT dyna DOT com, David Graff graff AT ldc DOT upenn DOT edu, Haobo Yu haoboy AT packetdesign DOT com, Pavlin Radoslavov pavlin AT catarina DOT usc DOT edu, Graham Phillips, Yuri Pradkin, Alefiya Hussain, Ya Xu, Michael Schwendt, Fabio Silva fabio AT isi DOT edu, Jerry Zhao zhaoy AT isi DOT edu, Ning Xu nxu AT aludra DOT usc DOT edu, Martin Lukac mlukac AT lecs DOT cs DOT ucla DOT edu, Xue Cai, Michael McQuaid, Christopher Meng, Calvin Ardi, H. Merijn Brand, Lan Wei, Hang Guo, Wes Hardaker.

Fsdb includes datasets contributed from NIST (DATA/nist_zarr13.fsdb), from <http://www.itl.nist.gov/div898/handbook/eda/section4/eda4281.htm>, the NIST/SEMATECH e-Handbook of Statistical Methods, section 1.4.2.8.1. Background and Data. The source is public domain, and reproduced with permission.

RELATED WORK

As stated in the introduction, Fsdb is an incompatible reimplementation of the ideas found in "/rdb". By storing data in simple text files and processing it with pipelines it is easy to experiment (in the shell) and look at the output. The original implementation of this idea was /rdb, a commercial product described in the book UNIX relational database management: application development in the UNIX environment by Rod Manis, Evan Schaffer, and Robert Jorgensen (and also at the web page <http://www.rdb.com/>).

While Fsdb is inspired by Rdb, it includes no code from it, and Fsdb makes several different design choices. In particular: rdb attempts to be closer to a "real" database, with provision for locking, file indexing. Fsdb focuses on single user use and so eschews these choices. Rdb also has some support for interactive editing. Fsdb leaves editing to text editors like emacs or vi.

In August, 2002 I found out Carlo Strozzi extended RDB with his package NoSQL <http://www.linux.it/~carlos/nosql/>. According to Mr. Strozzi, he implemented NoSQL in awk to avoid the Perl start-up of RDB. Although I haven’t found Perl startup overhead to be a big problem on my platforms (from old Sparcstation IPCs to 2GHz Pentium-4s), you may want to evaluate his system. The Linux Journal has a description of NoSQL at <http://www.linuxjournal.com/article/3294>. It seems quite similar to Fsdb. Like /rdb, NoSQL supports indexing (not present in Fsdb). Fsdb appears to have richer support for statistics, and, as of Fsdb-2.x, its support for Perl threading may support faster performance (one-process, less serialization and deserialization).

RELEASE NOTES

Versions prior to 1.0 were released informally on my web page but were not announced.

0.0 1991
started for my own research use

0.1 26-May-94
first check-in to RCS

0.2 15-Mar-95
parts now require perl5

1.0, 22-Jul-97
adds autoconf support and a test script.

1.1, 20-Jan-98
support for double space field separators, better tests

1.2, 11-Feb-98
minor changes and release on comp.lang.perl.announce

1.3, 17-Mar-98

adds median and quartile options to dbstats

adds dmalloc_to_db converter

fixes some warnings

dbjoin now can run on unsorted input

fixes a dbjoin bug

some more tests in the test suite

1.4, 27-Mar-98

improves error messages (all should now report the program that makes the error)

fixed a bug in dbstats output when the mean is zero

1.5, 25-Jun-98
BUG FIX
dbcolhisto, dbcolpercentile now handles non-numeric values like
dbstats
NEW
dbcolstats computes zscores and tscores over a column
NEW
dbcolscorrelate computes correlation coefficients between two
columns
INTERNAL
ficus_getopt.pl has been replaced by DbGetopt.pm
BUG FIX
all tests are now ’’portable’’ (previously some tests ran only
on my system)
BUG FIX
you no longer need to have the db programs in your path (fix
arose from a discussion with Arkadi Gelfond)
BUG FIX
installation no longer uses cp -f (to work on SunOS 4)

1.6, 24-May-99
NEW
dbsort, dbstats, dbmultistats now run in constant memory (using tmp
files if necessary)
NEW
dbcolmovingstats does moving means over a series of data
NEW
dbcol has a -v option to get all columns except those listed
NEW
dbmultistats does quartiles and medians
NEW
dbstripextraheaders now also cleans up bogus comments before the
fist header
BUG FIX
dbcolneaten works better with double-space-separated data

1.7, 5-Jan-00
NEW
dbcolize now detects and rejects lines that contain embedded copies
of the field separator
NEW
configure tries harder to prevent people from improperly
configuring/installing fsdb
NEW
tcpdump_to_db converter (incomplete)
NEW
tabdelim_to_db converter: from spreadsheet tab-delimited files to
db

NEW mailing lists for fsdb are

"fsdb-announce AT heidemann DOT la

DOT ca DOT us" and

"fsdb-talk AT heidemann DOT la DOT ca DOT us"

To subscribe to either, send mail to

"fsdb-announce-request AT heidemann DOT la DOT ca DOT us"

or "fsdb-talk-request AT heidemann DOT la DOT ca DOT us" with "subscribe" in the BODY of the message.

BUG FIX dbjoin used to produce incorrect output if there were extra,
unmatched values in the 2nd table. Thanks to Graham Phillips for
providing a test case.
BUG FIX
the sample commands in the usage strings now all should
explicitly include the source of data (typically from "cat foo.fsdb
|"). Thanks to Ya Xu for pointing out this documentation deficiency.
BUG FIX
( DOCUMENTATION ) dbcolmovingstats had incorrect sample output.

1.8, 28-Jun-00
BUG FIX
header options are now preserved when writing with dblistize
NEW
dbrowuniq now optionally checks for uniqueness only on certain
fields
NEW
dbrowsplituniq makes one pass through a file and splits it into
separate files based on the given fields
NEW
converter for "crl" format network traces
NEW
anywhere you use arbitrary code (like dbroweval), _last_foo now
maps to the last row’s value for field _foo.
OPTIMIZATION
comment processing slightly changed so that dbmultistats
now is much faster on files with lots of comments (for example, ~100k
lines of comments and 700 lines of data!) (Thanks to Graham Phillips
for pointing out this performance problem.)
BUG FIX
dbstats with median/quartiles now correctly handles singleton
data points.

1.9, 6-Nov-00
NEW
dbfilesplit, split a single input file into multiple output files
(based on code contributed by Pavlin Radoslavov).
BUG FIX
dbsort now works with perl-5.6

1.10, 10-Apr-01
BUG FIX
dbstats now handles the case where there are more n-tiles than
data
NEW
dbstats now includes a -S option to optimize work on pre-sorted
data (inspired by code contributed by Haobo Yu)
BUG FIX
dbsort now has a better estimate of memory usage when run on
data with very short records (problem detected by Haobo Yu)
BUG FIX
cleanup of temporary files is slightly better

1.11, 2-Nov-01
BUG FIX
dbcolneaten now runs in constant memory
NEW
dbcolneaten now supports "field specifiers" that allow some control
over how wide columns should be
OPTIMIZATION
dbsort now tries hard to be filesystem cache-friendly
(inspired by "Information and Control in Gray-box Systems" by the
Arpaci-Dusseau’s at SOSP 2001 )
INTERNAL
t_distr now ported to perl5 module DbTDistr

1.12, 30-Oct-02
BUG FIX
dbmultistats documentation typo fixed
NEW
dbcolmultiscale
NEW
dbcol has -r option for "relaxed error checking"
NEW
dbcolneaten has new -e option to strip end-of-line spaces
NEW
dbrow finally has a -v option to negate the test
BUG FIX
math bug in dbcoldiff fixed by Ashvin Goel (need to check
Scheaffer test cases)
BUG FIX
some patches to run with Perl 5.8. Note: some programs
(dbcolmultiscale, dbmultistats, dbrowsplituniq) generate warnings like:
"Use of uninitialized value in concatenation (.)" or "string at
/usr/lib/perl5/5.8.0/FileCache.pm line 98, < STDIN > line 2". Please
ignore this until I figure out how to suppress it. (Thanks to Jerry
Zhao for noticing perl-5.8 problems.)
BUG FIX
fixed an autoconf problem where configure would fail to find a
reasonable prefix (thanks to Fabio Silva for reporting the problem)
NEW
db_to_html_table: simple conversion to html tables ( NO fancy stuff)
NEW
dblib now has a function dblib_text2html() that will do simple
conversion of iso-8859-1 to HTML

1.13, 4-Feb-04
NEW
fsdb added to the freebsd ports tree
<http://www.freshports.org/databases/fsdb/>. Maintainer: "larse AT isi
DOT edu"
BUG FIX
properly handle trailing spaces when data must be numeric (ex.
dbstats with -FS, see test dbstats_trailing_spaces). Fix from Ning Xu
"nxu AT aludra DOT usc DOT edu".
NEW
dbcolize error message improved (bug report from Terrence Brannon),
and list format documented in the README.
NEW
cgi_to_db converts CGI .pm-format storage to fsdb list format
BUG FIX
handle numeric synonyms for column names in dbcol properly
ENHANCEMENT
"talking about columns" section added to README. Lack of
documentation pointed out by Lars Eggert.
CHANGE
dbformmail now defaults to using Mail ("Berkeley Mail") to send
mail, rather than sendmail (sendmail is still an option, but mail
doesn’t require running as root)
NEW
on platforms that support it (i.e., with perl 5.8), fsdb works fine
with unicode
NEW
dbfilevalidate: check a db file for some common errors

1.14, 24-Aug-06
ENHANCEMENT README
cleanup
INCOMPATIBLE CHANGE
dbcolsplit renamed dbcolsplittocols
NEW
dbcolsplittorows split one column into multiple rows
NEW
dbcolsregression compute linear regression and correlation for two
columns
ENHANCEMENT
cvs_to_db: better error handling, normalize field names,
skip blank lines
ENHANCEMENT
dbjoin now detects (and fails) if non-joined files have
duplicate names
BUG FIX
minor bug fixed in calculation of Student t-distributions
(doesn’t change any test output, but may have caused small errors)

1.15, 12-Nov-07
NEW
fsdb-1.14 added to the MacOS Fink system
<http://pdb.finkproject.org/pdb/package.php/fsdb>. (Thanks to Lars
Eggert for maintaining this port.)
NEW
Fsdb::IO::Reader and Fsdb::IO::Writer now provide reasonably clean
OO I/O
interfaces to Fsdb files. Highly recommended if you use fsdb
directly from perl. In the fullness of time I expect to reimplement
the entire thing using these APIs to replace the current dblib.pl which
is still hobbled by its roots in perl4.
NEW
dbmapreduce now implements a Google-style map/reduce abstraction,
generalizing dbmultistats.
ENHANCEMENT
fsdb now uses the Perl build system (Makefile.PL, etc.),
instead of autoconf. This change paves the way to better perl-5-style
modularization, proper manual pages, input of both listize and colize
format for every program, and world peace.
ENHANCEMENT
dblib.pl is now moved to Fsdb::Old.pm.
BUG FIX
dbmultistats now propagates its format argument (-f). Bug and
fix from Martin Lukac (thanks!).
ENHANCEMENT
dbformmail documentation now is clearer that it doesn’t
send the mail, you have to run the shell script it writes. (Problem
observed by Unkyu Park.)
ENHANCEMENT
adapted to autoconf-2.61 (and then these changes were
discarded in favor of The Perl Way.
BUG FIX
dbmultistats memory usage corrected (O(# tags), not O(1))
ENHANCEMENT
dbmultistats can now optionally run with pre-grouped input
in O(1) memory
ENHANCEMENT
dbroweval -N was finally implemented (eat comments)

2.0, 25-Jan-08
2.0, 25-Jan-08 --- a quiet 2.0 release (gearing up towards complete)
ENHANCEMENT:
shifting old programs to Perl modules, with the front-end
program as just a wrapper. In the short-term, this change just means
programs have real man pages. In the long-run, it will mean that one
can run a pipeline in a single Perl program. So far: dbcol, dbroweval,
the new dbrowcount. dbsort the new dbmerge, the old "dbstats" (renamed
dbcolstats), dbcolrename, dbcolcreate,
NEW:
Fsdb::Filter::dbpipeline is an internal-only module that lets one
use fsdb commands from within perl (via threads).

It also provides perl function aliases for the internal modules, so a string of fsdb commands in perl are nearly as terse as in the shell:

use Fsdb::Filter::dbpipeline qw(:all);
dbpipeline(
dbrow(qw(name test1)),
dbroweval('_test1 += 5;')
);

INCOMPATIBLE CHANGE: The old dbcolstats has been renamed
dbcolstatscores. The new dbcolstats does the same thing as the old
dbstats. This incompatibility is unfortunate but normalizes program
names.
CHANGE:
The new dbcolstats program always outputs "-" (the default
empty value) for statistics it cannot compute (for example, standard
deviation if there is only one row), instead of the old mix of "-" and
"na".
INCOMPATIBLE CHANGE:
The old dbcolstats program, now called
dbcolstatscores, also has different arguments. The "-t mean,stddev"
option is now "--tmean mean --tstddev stddev". See dbcolstatscores for
details.
INCOMPATIBLE CHANGE:
dbcolcreate now assumes all new columns get the
default value rather than requiring each column to have an initial
constant value. To change the initial value, sue the new "-e" option.
NEW:
dbrowcount counts rows, an almost-subset of dbcolstats’s "n"
output (except without differentiating numeric/non-numeric input), or
the equivalent of "dbstripcomments | wc -l".
NEW:
dbmerge merges two sorted files. This functionality was previously
embedded in dbsort.
INCOMPATIBLE CHANGE:
dbjoin’s "-i" option to include non-matches is now
renamed "-a", so as to not conflict with the new standard option "-i"
for input file.

2.1, 6-Apr-08
2.1, 6-Apr-08 --- another alpha 2.0, but now all converted programs understand both listize and colize format
ENHANCEMENT:
shifting more old programs to Perl modules. New in 2.1:
dbcolneaten, dbcoldefine, dbcolhisto, dblistize, dbcolize, dbrecolize
ENHANCEMENT
dbmerge now handles an arbitrary number of input files, not
just exactly two.
NEW
dbmerge2 is an internal routine that handles merging exactly two
files.
INCOMPATIBLE CHANGE
dbjoin now specifies inputs like dbmerge2, rather
than assuming the first two arguments were tables (as in fsdb-1).

The old dbjoin argument "-i" is now "-a" or <--type=outer>.

A minor change: comments in the source files for dbjoin are now intermixed with output rather than being delayed until the end.

ENHANCEMENT dbsort now no longer produces warnings when null values are
passed to numeric comparisons.
BUG FIX
dbroweval now once again works with code that lacks a trailing
semicolon. (This bug fixes a regression from 1.15.)
INCOMPATIBLE CHANGE
dbcolneaten’s old "-e" option (to avoid end-of-line
spaces) is now "-E" to avoid conflicts with the standard empty field
argument.
INCOMPATIBLE CHANGE
dbcolhisto’s old "-e" option is now "-E" to avoid
conflicts. And its "-n", "-s", and "-w" are now "-N", "-S", and "-W" to
correspond.
NEW
dbfilealter replaces dbrecolize, dblistize, and dbcolize, but with
different options.
ENHANCEMENT
The library routines "Fsdb::IO" now understand both
list-format and column-format data, so all converted programs can now
automatically
read either format. This capability was one of the
milestone goals for 2.0, so yea!

2.2, 23-May-08
Release 2.2 is another 2.x alpha release. Now most of the commands are ported, but a few remain, and I plan one last incompatible change (to the file header) before 2.x final.
ENHANCEMENT

shifting more old programs to Perl modules. New in 2.2: dbrowaccumulate, dbformmail. dbcolmovingstats. dbrowuniq. dbrowdiff. dbcolmerge. dbcolsplittocols. dbcolsplittorows. dbmapreduce. dbmultistats. dbrvstatdiff. Also dbrowenumerate exists only as a front-end (command-line) program.

INCOMPATIBLE CHANGE

The following programs have been dropped from fsdb-2.x: dbcoltighten, dbfilesplit, dbstripextraheaders, dbstripleadingspace.

NEW

combined_log_format_to_db to convert Apache logfiles

INCOMPATIBLE CHANGE

Options to dbrowdiff are now -B and -I, not -a and -i.

INCOMPATIBLE CHANGE

dbstripcomments is now dbfilestripcomments.

BUG FIXES

dbcolneaten better handles empty columns; dbcolhisto warning suppressed (actually a bug in high-bucket handling).

INCOMPATIBLE CHANGE

dbmultistats now requires a "-k" option in front of the key (tag) field, or if none is given, it will group by the first field (both like dbmapreduce).

KNOWN BUG

dbmultistats with quantile option doesn’t work currently.

INCOMPATIBLE CHANGE

dbcoldiff is renamed dbrvstatdiff.

BUG FIXES

dbformmail was leaving its log message as a command, not a comment. Oops. No longer.

2.3, 27-May-08 (alpha)
Another alpha release, this one just to fix the critical dbjoin bug listed below (that happens to have blocked my MP3 jukebox :-).
BUG FIX

Dbsort no longer hangs if given an input file with no rows.

BUG FIX

Dbjoin now works with unsorted input coming from a pipeline (like stdin). Perl-5.8.8 has a bug (?) that was making this case fail---opening stdin in one thread, reading some, then reading more in a different thread caused an lseek which works on files, but fails on pipes like stdin. Go figure.

BUG FIX / KNOWN BUG

The dbjoin fix also fixed dbmultistats -q (it now gives the right answer). Although a new bug appeared, messages like:
Attempt to free unreferenced scalar: SV 0xa9dd0c4, Perl interpreter: 0xa8350b8 during global destruction. So the dbmultistats_quartile test is still disabled.

2.4, 18-Jun-08
Another alpha release, mostly to fix minor usability problems in dbmapreduce and client functions.
ENHANCEMENT

dbrow now defaults to running user supplied code without warnings (as with fsdb-1.x). Use "--warnings" or "-w" to turn them back on.

ENHANCEMENT

dbroweval can now write different format output than the input, using the "-m" option.

KNOWN BUG

dbmapreduce emits warnings on perl 5.10.0 about "Unbalanced string table refcount" and "Scalars leaked" when run with an external program as a reducer.

dbmultistats emits the warning "Attempt to free unreferenced scalar" when run with quartiles.

In each case the output is correct. I believe these can be ignored.

CHANGE

dbmapreduce no longer logs a line for each reducer that is invoked.

2.5, 24-Jun-08
Another alpha release, fixing more minor bugs in "dbmapreduce" and lossage in "Fsdb::IO".
ENHANCEMENT

dbmapreduce can now tolerate non-map-aware reducers that pass back the key column in put. It also passes the current key as the last argument to external reducers.

BUG FIX

Fsdb::IO::Reader, correctly handle "-header" option again. (Broken since fsdb-2.3.)

2.6, 11-Jul-08
Another alpha release, needed to fix DaGronk. One new port, small bug fixes, and important fix to dbmapreduce.
ENHANCEMENT

shifting more old programs to Perl modules. New in 2.2: dbcolpercentile.

INCOMPATIBLE CHANGE and ENHANCEMENTS dbcolpercentile arguments changed,
use "--rank" to require ranking instead of "-r". Also, "--ascending"
and "--descending" can now be specified separately, both for
"--percentile" and "--rank".
BUG FIX

Sigh, the sense of the --warnings option in dbrow was inverted. No longer.

BUG FIX

I found and fixed the string leaks (errors like "Unbalanced string table refcount" and "Scalars leaked") in dbmapreduce and dbmultistats. (All "IO::Handle"s in threads must be manually destroyed.)

BUG FIX

The "-C" option to specify the column separator in dbcolsplittorows now works again (broken since it was ported).

2.7, 30-Jul-08 beta

The beta release of fsdb-2.x. Finally, all programs are ported. As statistics, the number of lines of non-library code doubled from 7.5k to 15.5k. The libraries are much more complete, going from 866 to 5164 lines. The overall number of programs is about the same, although 19 were dropped and 11 were added. The number of test cases has grown from 116 to 175. All programs are now in perl-5, no more shell scripts or perl-4. All programs now have manual pages.

Although this is a major step forward, I still expect to rename "jdb" to "fsdb".
ENHANCEMENT

shifting more old programs to Perl modules. New in 2.7: dbcolscorellate. dbcolsregression. cgi_to_db. dbfilevalidate. db_to_csv. csv_to_db, db_to_html_table, kitrace_to_db, tcpdump_to_db, tabdelim_to_db, ns_to_db.

INCOMPATIBLE CHANGE

The following programs have been dropped from fsdb-2.x: db2dcliff, dbcolmultiscale, crl_to_db. ipchain_logs_to_db. They may come back, but seemed overly specialized. The following program dbrowsplituniq was dropped because it is superseded by dbmapreduce. dmalloc_to_db was dropped pending a test cases and examples.

ENHANCEMENT

dbfilevalidate now has a "-c" option to correct errors.

NEW

html_table_to_db provides the inverse of db_to_html_table.

2.8, 5-Aug-08
Change header format, preserving forwards compatibility.
BUG FIX

Complete editing pass over the manual, making sure it aligns with fsdb-2.x.

SEMI-COMPATIBLE CHANGE

The header of fsdb files has changed, it is now #fsdb, not #h (or #L) and parsing of -F and -R are also different. See dbfilealter for the new specification. The v1 file format will be read, compatibly, but not written.

BUG FIX

dbmapreduce now tolerates comments that precede the first key, instead of failing with an error message.

2.9, 6-Aug-08
Still in beta; just a quick bug-fix for dbmapreduce.
ENHANCEMENT

dbmapreduce now generates plausible output when given no rows of input.

2.10, 23-Sep-08
Still in beta, but picking up some bug fixes.
ENHANCEMENT

dbmapreduce now generates plausible output when given no rows of input.

ENHANCEMENT

dbroweval the warnings option was backwards; now corrected. As a result, warnings in user code now default off (like in fsdb-1.x).

BUG FIX

dbcolpercentile now defaults to assuming the target column is numeric. The new option "-N" allows selection of a non-numeric target.

BUG FIX

dbcolscorrelate now includes "--sample" and "--nosample" options to compute the sample or full population correlation coefficients. Thanks to Xue Cai for finding this bug.

2.11, 14-Oct-08
Still in beta, but picking up some bug fixes.
ENHANCEMENT

html_table_to_db is now more aggressive about filling in empty cells with the official empty value, rather than leaving them blank or as whitespace.

ENHANCEMENT

dbpipeline now catches failures during pipeline element setup and exits reasonably gracefully.

BUG FIX

dbsubprocess now reaps child processes, thus avoiding running out of processes when used a lot.

2.12, 16-Oct-08
Finally, a full (non-beta) 2.x release!
INCOMPATIBLE CHANGE

Jdb has been renamed Fsdb, the flatfile-streaming database. This change affects all internal Perl APIs, but no shell command-level APIs. While Jdb served well for more than ten years, it is easily confused with the Java debugger (even though Jdb was there first!). It also is too generic to work well in web search engines. Finally, Jdb stands for ’’John’s database’’, and we’re a bit beyond that. (However, some call me the ’’file-system guy’’, so one could argue it retains that meeting.)

If you just used the shell commands, this change should not affect you. If you used the Perl-level libraries directly in your code, you should be able to rename "Jdb" to "Fsdb" to move to 2.12.

The jdb-announce list not yet been renamed, but it will be shortly.

With this release I’ve accomplished everything I wanted to in fsdb-2.x. I therefore expect to return to boring, bugfix releases.

2.13, 30-Oct-08
BUG FIX

dbrowaccumulate now treats non-numeric data as zero by default.

BUG FIX

Fixed a perl-5.10ism in dbmapreduce that breaks that program under 5.8. Thanks to Martin Lukac for reporting the bug.

2.14, 26-Nov-08
BUG FIX

Improved documentation for dbmapreduce’s "-f" option.

ENHANCEMENT

dbcolmovingstats how computes a moving standard deviation in addition to a moving mean.

2.15, 13-Apr-09
BUG FIX

Fix a make install bug reported by Shalindra Fernando.

2.16, 14-Apr-09
BUG FIX

Another minor release bug: on some systems programize_module looses executable permissions. Again reported by Shalindra Fernando.

2.17, 25-Jun-09
TYPO FIXES

Typo in the dbroweval manual fixed.

IMPROVEMENT

There is no longer a comment line to label columns in dbcolneaten, instead the header line is tweaked to line up. This change restores the Jdb-1.x behavior, and means that repeated runs of dbcolneaten no longer add comment lines each time.

BUG FIX

It turns out dbcolneaten was not correctly handling trailing spaces when given the "-E" option to suppress them. This regression is now fixed.

EXTENSION

dbroweval(1) can now handle direct references to the last row via $lfref, a dubious but now documented feature.

BUG FIXES

Separators set with "-C" in dbcolmerge and dbcolsplittocols were not properly setting the heading, and null fields were not recognized. The first bug was reported by Martin Lukac.

2.18, 1-Jul-09 A minor release
IMPROVEMENT

Documentation for Fsdb::IO::Reader has been improved.

IMPROVEMENT

The package should now be PGP-signed.

2.19, 10-Jul-09
BUG FIX

Internal improvements to debugging output and robustness of dbmapreduce and dbpipeline. TEST/dbpipeline_first_fails.cmd re-enabled.

2.20, 30-Nov-09 (A collection of minor bugfixes, plus a build against Fedora 12.)
BUG FIX

Loging for dbmapreduce with code refs is now stable (it no longer includes a hex pointer to the code reference).

BUG FIX

Better handling of mixed blank lines in Fsdb::IO::Reader (see test case dbcolize_blank_lines.cmd).

BUG FIX

html_table_to_db now handles multi-line input better, and handles tables with COLSPAN.

BUG FIX

dbpipeline now cleans up threads in an "eval" to prevent "cannot detach a joined thread" errors that popped up in perl-5.10. Hopefully this prevents a race condition that causes the test suites to hang about 20% of the time (in dbpipeline_first_fails).

IMPROVEMENT

dbmapreduce now detects and correctly fails when the input and reducer have incompatible field separators.

IMPROVEMENT

dbcolstats, dbcolhisto, dbcolscorrelate, dbcolsregression, and dbrowcount now all take an "-F" option to let one specify the output field separator

BUG FIX

An omitted "-k" from the manual page of dbmultistats is now there. Bug reported by Unkyu Park.

2.21, 17-Apr-10 bug fix release
BUG FIX

Fsdb::IO::Writer now no longer fails with -outputheader => never (an obscure bug).

IMPROVEMENT

Fsdb (in the warnings section) and dbcolstats now more carefully document how they handle (and do not handle) numerical precision problems, and other general limits. Thanks to Yuri Pradkin for prompting this documentation.

IMPROVEMENT

"Fsdb::Support::fullname_to_sortkey" is now restored from "Jdb".

IMPROVEMENT

Documention for multiple styles of input approaches (including performance description) added to Fsdb::IO.

2.22, 2010-10-31 One new tool dbcolcopylast and several bug fixes for Perl 5.10.
BUG FIX

dbmerge now correctly handles n-way merges. Bug reported by Yuri Pradkin.

INCOMPARABLE CHANGE

dbcolneaten now defaults to not padding the last column.

ADDITION

dbrowenumerate now takes -N NewColumn to give the new column a name other than "count". Feature requested by Mike Rouch in January 2005.

ADDITION

New program dbcolcopylast copies the last value of a column into a new column copylast_column of the next row. New program requested by Fabio Silva; useful for converting dbmultistats output into dbrvstatdiff input.

BUG FIX

Several tools (particularly dbmapreduce and dbmultistats) would report errors like "Unbalanced string table refcount: (1) for " STDOUT" during global destruction" on exit, at least on certain versions of Perl (for me on 5.10.1), but similar errors have been off-and-on for several Perl releases. Although I think my code looked OK, I worked around this problem with a different way of handling standard IO redirection.

2.23, 2011-03-10 Several small portability bugfixes; improved dbcolstats for large datasets
IMPROVEMENT

Documentation to dbrvstatdiff was changed to use "sd" to refer to standard deviation, not "ss" (which might be confused with sum-of-squares).

BUG FIX

This documentation about dbmultistats was missing the -k option in some cases.

BUG FIX

dbmapreduce was failing on MacOS-10.6.3 for some tests with the error

dbmapreduce: cannot run external dbmapreduce reduce program (perl TEST/dbmapreduce_external_with_key.pl)

The problem seemed to be only in the error, not in operation. On MacOS, the error is now suppressed. Thanks to Alefiya Hussain for providing access to a Mac system that allowed debugging of this problem.

IMPROVEMENT

The csv_to_db command requires an external Perl library (Text::CSV_XS). On computers that lack this optional library, previously Fsdb would configure with a warning and then test cases would fail. Now those test cases are skipped with an additional warning.

BUG FIX

The test suite now supports alternative valid output, as a hack to account for last-digit floating point differences. (Not very satisfying :-(

BUG FIX

dbcolstats output for confidence intervals on very large datasets has changed. Previously it failed for more than 2^31-1 records, and handling of T-Distributions with thousands of rows was a bit dubious. Now datasets with more than 10000 are considered infinitely large and hopefully correctly handled.

2.24, 2011-04-15 Improvements to fix an old bug in dbmapreduce with different field separators
IMPROVEMENT

The dbfilealter command had a "--correct" option to work-around from incompatible field-separators, but it did nothing. Now it does the correct but sad, data-loosing thing.

IMPROVEMENT

The dbmultistats command previously failed with an error message when invoked on input with a non-default field separator. The root cause was the underlying dbmapreduce that did not handle the case of reducers that generated output with a different field separator than the input. We now detect and repair incompatible field separators. This change corrects a problem originally documented and detected in Fsdb-2.20. Bug re-reported by Unkyu Park.

2.25, 2011-08-07 Two new tools, xml_to_db and dbfilepivot, and a bugfix for two people.
IMPROVEMENT

kitrace_to_db now supports a --utc option, which also fixes this test case for users outside of the Pacific time zone. Bug reported by David Graff, and also by Peter Desnoyers (within a week of each other :-)

NEW

xml_to_db can convert simple, very regular XML files into Fsdb.

NEW

dbfilepivot "pivots" a file, converting multiple rows corresponding to the same entity into a single row with multiple columns.

2.26, 2011-12-12 Bug fixes, particularly for perl-5.14.2.
BUG FIX

Bugs fixed in Fsdb::IO::Reader(3) manual page.

BUG FIX

Fixed problems where dbcolstats was truncating floating point numbers when sorting. This strange behavior happens as of perl-5.14.2 and it seems like a Perl bug. I’ve worked around it for the test suites, but I’m a bit nervous.

2.27, 2012-11-15 Accumulated bug fixes.
IMPROVEMENT

csv_to_db now reports errors in CVS input with real diagnostics.

IMPROVEMENT

dbcolmovingstats can now compute median, when given the "-m" option.

BUG FIX

dbcolmovingstats non-numeric handling (the "-a" option) now works properly.

DOCUMENTATION

The internal t/test_command.t test framework is now documented.

BUG FIX

dbrowuniq now correctly handles the case where there is no input (previously it output a blank line, which is a malformed fsdb file). Thanks to Yuri Pradkin for reporting this bug.

2.28, 2012-11-15 A quick release to fix most rpmlint errors.
BUG FIX

Fixed a number of minor release problems (wrong permissions, old FSF address, etc.) found by rpmlint.

2.29, 2012-11-20 a quick release for CPAN testing
IMPROVEMENT

Tweaked the RPM spec.

IMPROVEMENT

Modified Makefile.PL to fail gracefully on Perl installations that lack threads. (Without this fix, I get massive failures in the non-ithreads test system.)

2.30, 2012-11-25 improvements to perl portability
BUG FIX

Removed unicode character in documention of dbcolscorrelated so pod tests will pass. (Sigh, that should work :-( )

BUG FIX

Fixed test suite failures on 5 tests (dbcolcreate_double_creation was the first) due to Carp’s addition of a period. This problem was breaking Fsdb on perl-5.17. Thanks to Michael McQuaid for helping diagnose this problem.

IMPROVEMENT

The test suite now prints out the names of tests it tries.

2.31, 2012-11-28 A release with actual improvements to dbfilepivot and dbrowuniq.
BUG FIX

Documentation fixes: typos in dbcolscorrelated, bugs in dbfilepivot, clarification for comment handling in Fsdb::IO::Reader.

IMPROVEMENT

Previously dbfilepivot assumed the input was grouped by keys and didn’t very that pre-condition. Now there is no pre-condition (it will sort the input by default), and it checks if the invariant is violated.

BUG FIX

Previously dbfilepivot failed if the input had comments (oops :-); no longer.

IMPROVEMENT

Now dbrowuniq has the "-L" option to preserve the last unique row (instead of the first), a common idiom.

2.32, 2012-12-21 Test suites should now be more numerically robust.

NEW

New dbfilediff does fsdb-aware file differencing. It does not do smart intuition of add/removes like Unix diff(1), but it does know about columns, and with "-E", it does numeric-aware differences.

IMPROVEMENT

Test suites that are numeric now use dbfilediff to do numeric-aware comparisons, so the test suite should now be robust to slightly different computers and operating systems and compilers than exactly what I use.

2.33, 2012-12-23 Minor fixes to some test cases.
IMPROVEMENT

dbfilediff and dbrowuniq now supports the "-N" option to give the new column a different name. (And a test cases where this duplication mattered have been fixed.)

IMPROVEMENT

dbrvstatdiff now show the t-test breakpoint with a reasonable number of floating point digits.

BUG FIX

Fixed a numerical stability problem in the dbroweval_last test case.

WHAT’S NEW

2.34, 2013-02-10 Parallelism in dbmerge.
IMPROVEMENT

Documention for dbjoin now includes resource requirements.

IMPROVEMENT

Default memory usage for dbsort is now about 256MB. (The world keeps moving forward.)

IMPROVEMENT

dbmerge now does merging in parallel. As a side-effect, dbsort should be faster when input overflows memory. The level of parallelism can be limited with the "--parallelism" option. (There is more work to do here, but we’re off to a start.)

2.35, 2013-02-23 Improvements to dbmerge parallelism
BUG FIX

Fsdb temporary files are now created more securely (with File::Temp).

IMPROVEMENT

Programs that sort or merge on fields (dbmerge2, dbmerge, dbsort, dbjoin) now report an error if no fields on which to join or merge are given.

IMPROVEMENT

Parallelism in dbmerge is should now be more consistent, with less starting and stopping.

IMPROVEMENT In dbmerge, the "--xargs" option lets one give input
filenames on standard input, rather than the command line. This feature
paves the way for faster dbsort for large inputs (by pipelining sorting
and merging), expected in the next release.

2.36, 2013-02-25 dbsort pipelines with dbmerge
IMPROVEMENT
For large inputs, dbsort now pipelines sorting and merging,
allowing earlier processing.
BUG FIX
Since 2.35, dbmerge delayed cleanup of intermediate files,
thereby requiring extra disk space.

2.37, 2013-02-26 quick bugfix to support parallel sort and merge from recent releases
BUG FIX
Since 2.35, dbmerge delayed removal of input files given by
"--xargs". This problem is now fixed.

2.38, 2013-04-29 minor bug fixes
CLARIFICATION

Configure now rejects Windows since tests seem to hang on some versions of Windows. (I would love help from a Windows developer to get this problem fixed, but I cannot do it.) See https://rt.cpan.org/Ticket/Display.html?id=84201.

IMPROVEMENT

All programs that use temporary files (dbcolpercentile, dbcolscorrelate, dbcolstats, dbcolstatscores) now take the "-T" option and set the temporary directory consistently.

In addition, error messages are better when the temporary directory has problems. Problem reported by Liang Zhu.

BUG FIX

dbmapreduce was failing with external, map-reduce aware reducers (when invoked with -M and an external program). (Sigh, did this case ever work?) This case should now work. Thanks to Yuri Pradkin for reporting this bug (in 2011).

BUG FIX

Fixed perl-5.10 problem with dbmerge. Thanks to Yuri Pradkin for reporting this bug (in 2013).

2.39, date 2013-05-31 quick release for the dbrowuniq extension
BUG FIX

Actually in 2.38, the Fedora .spec got cleaner dependencies. Suggestion from Christopher Meng via <https://bugzilla.redhat.com/show_bug.cgi?id=877096>.

ENHANCEMENT

Fsdb files are now explicitly set into UTF-8 encoding, unless one specifies "-encoding" to "Fsdb::IO".

ENHANCEMENT

dbrowuniq now supports "-I" for incremental counting.

2.40, 2013-07-13 small bug fixes
BUG FIX

dbsort now has more respect for a user-given temporary directory; it no longer is ignored for merging.

IMPROVEMENT

dbrowuniq now has options to output the first, last, and both first and last rows of a run ("-F", "-L", and "-B").

BUG FIX

dbrowuniq now correctly handles "-N". Sigh, it didn’t work before.

2.41, 2013-07-29 small bug and packaging fixes
ENHANCEMENT

Documentation to dbrvstatdiff improved (inspired by questions from Qian Kun).

BUG FIX

dbrowuniq no longer duplicates singleton unique lines when outputting both (with "-B").

BUG FIX

Add missing "XML::Simple" dependency to Makefile.PL.

ENHANCEMENT

Tests now show the diff of the failing output if run with "make test TEST_VERBOSE=1".

ENHANCEMENT

dbroweval now includes documentation for how to output extra rows. Suggestion from Yuri Pradkin.

BUG FIX

Several improvements to the Fedora package from Michael Schwendt via <https://bugzilla.redhat.com/show_bug.cgi?id=877096>, and from the harsh master that is rpmlint. (I am stymied at teaching it that "outliers" is spelled correctly. Maybe I should send it Schneier’s book. And an unresolvable invalid-spec-name lurks in the SRPM. )

2.42, 2013-07-31 A bug fix and packaging release.
ENHANCEMENT

Documentation to dbjoin improved to better memory usage. (Based on problem report by Lin Quan.)

BUG FIX

The .spec is now perl-Fsdb.spec to satisfy rpmlint. Thanks to Christopher Meng for a specific bug report.

BUG FIX

Test dbroweval_last.cmd no longer has a column that caused failures because of numerical instability.

BUG FIX

Some tests now better handle bugs in old versions of perl (5.10, 5.12). Thanks to Calvin Ardi for help debugging this on a Mac with perl-5.12, but the fix should affect other platforms.

2.43, 2013-08-27 Adds in-file compression.
BUG FIX

Changed the sort on TEST/dbsort_merge.cmd to strings (from numerics) so we’re less susceptible to false test-failures due to floating point IO differences.

EXPERIMENTAL ENHANCEMENT

Yet more parallelism in dbmerge: new "endgame-mode" builds a merge tree of processes at the end of large merge tasks to get maximally parallelism. Currently this feature is off by default because it can hang for some inputs. Enable this experimental feature with "--endgame".

ENHANCEMENT

"Fsdb::IO" now handles being given "IO::Pipe" objects (as exercised by dbmerge).

BUG FIX

Handling of NamedTmpfiles now supports concurrency. This fix will hopefully fix occasional "Use of uninitialized value $_ in string ne at ...NamedTmpfile.pm line 93." errors.

BUG FIX

Fsdb now requires perl 5.10. This is a bug fix because some test cases used to require it, but this fact was not properly documented. (Back-porting to 5.008 would require removing all "//" operators.)

ENHANCEMENT

Fsdb now handles automatic compression of file contents. Enable compression with "dbfilealter -Z xz" (or "gz" or "bz2"). All programs should operate on compressed files and leave the output with the same level of compression. "xz" is recommended as fastest and most efficient. "gz" is produces unrepeatable output (and so has no output test), it seems to insist on adding a timestamp.

2.44, 2013-10-02 A major change--all threads are gone.
ENHANCEMENT

Fsdb is now thread free and only uses processes for parallelism. This change is a big change--the entire motivation for Fsdb-2 was to exploit parallelism via threading. Parallelism--good, but perl threading--bad for performance. Horribly bad for performance. About 20x worse than pipes on my box. (See perl bug #119445 for the discussion.)

NEW

"Fsdb::Support::Freds" provides a thread-like abstraction over forking, with some nice support for callbacks in the parent upon child termination.

ENHANCEMENT

Details about removing threads: "dbpipeline" is thread free, and new tests to verify each of its parts. The easy cases are "dbcolpercentile", "dbcolstats", "dbfilepivot", "dbjoin", and "dbcolstatscores", each of which use it in simple ways (2013-09-09). "dbmerge" is now thread free (2013-09-13), but was a significant rewrite, which brought "dbsort" along. "dbmapreduce" is partly thread free (2013-09-21), again as a rewrite, and it brings "dbmultistats" along. Full "dbmapreduce" support took much longer (2013-10-02).

BUG FIX

When running with user-only output ("-n"), dbroweval now resets the output vector $ofref after it has been output.

NEW

dbcolcreate will create all columns at the head of each row with the "--first" option.

NEW

dbfilecat will concatenate two files, verifying that they have the same schema.

ENHANCEMENT

dbmapreduce now passes comments through, rather than eating them as before.

Also, dbmapreduce now supports a "--" option to prevent misinterpreting sub-program parameters as for dbmapreduce.

INCOMPATIBLE CHANGE

dbmapreduce no longer figures out if it needs to add the key to the output. For multi-key-aware reducers, it never does (and cannot). For non-multi-key-aware reducers, it defaults to add the key and will now fail if the reducer adds the key (with error "dbcolcreate: attempt to create pre-existing column..."). In such cases, one must disable adding the key with the new option "--no-prepend-key".

INCOMPATIBLE CHANGE

dbmapreduce no longer copies the input field separator by default. For multi-key-aware reducers, it never does (and cannot). For non-multi-key-aware reducers, it defaults to not copying the field separator, but it will copy it (the old default) with the "--copy-fs" option

2.45, 2013-10-07 cleanup from de-thread-ification
BUG FIX

Corrected a fast busy-wait in dbmerge.

ENHANCEMENT

Endgame mode enabled in dbmerge; it (and also large cases of dbsort) should now exploit greater parallelism.

BUG FIX

Test case with "Fsdb::BoundedQueue" (gone since 2.44) now removed.

2.46, 2013-10-08 continuing cleanup of our no-threads version
BUG FIX

Fixed some packaging details. (Really, threads are no longer required, missing tests in the MANIFEST. )

IMPROVEMENT

dbsort now better communicates with the merge process to avoid bursty parallelism.

Fsdb::IO::Writer now can take "-autoflush =" 1> for line-buffered IO.

2.47, 2013-10-12 test suite cleanup for non-threaded perls
BUG FIX

Removed some stray "use threads" in some test cases. We didn’t need them, and these were breaking non-threaded perls.

BUG FIX

Better handling of Fred cleanup; should fix intermittent dbmapreduce failures on BSD.

ENHANCEMENT

Improved test framework to show output when tests fail. (This time, for real.)

2.48, 2014-01-03 small bugfixes and improved release engineering
ENHANCEMENT

Test suites now skip tests for libraries that are missing. (Patch for missing "IO::Compresss:Xz" contributed by Calvin Ardi.)

ENHANCEMENT

Removed references to Jdb in the package specification. Since the name was changed in 2008, there’s no longer a huge need for backwards compatibility. (Suggestion form Petr Šabata.)

ENHANCEMENT

Test suites now invoke the perl using the path from $Config{perlpath}. Hopefully this helps testing in environments where there are multiple installed perls and the default perl is not the same as the perl-under-test (as happens in cpantesters.org).

BUG FIX

Added specific encoding to this manpage to account for Unicode. Required to build correctly against perl-5.18.

2.49, 2014-01-04 bugfix to unicode handling in Fsdb IO (plus minor packaging fixes)
BUG FIX

Restored a line in the .spec to chmod g-s.

BUG FIX

Unicode decoding is now handled correctly for programs that read from standard input. (Also: New test scripts cover unicode input and output.)

BUG FIX

Fix to Fsdb documentation encoding line. Addresses test failure in perl-5.16 and earlier. (Who knew "encoding" had to be followed by a blank line.)

WHAT’S NEW

2.50, 2014-05-27 a quick release for spec tweaks
ENHANCEMENT

In dbroweval, the "-N" (no output, even comments) option now implies "-n", and it now suppresses the header and trailer.

BUG FIX

A few more tweaks to the perl-Fsdb.spec from Petr Šabata.

BUG FIX

Fixed 3 uses of "use v5.10" in test suites that were causing test failures (due to warnings, not real failures) on some platforms.

2.51, 2014-09-05 Feature enhancements to dbcolmovingstats, dbcolcreate, dbmapreduce, and new sqlselect_to_db
ENHANCEMENT

dbcolcreate now has a "--no-recreate-fatal" that causes it to ignore creation of existing columns (instead of failing).

ENHANCEMENT

dbmapreduce once again is robust to reducers that output the key; "--no-prepend-key" is no longer mandatory.

ENHANCEMENT

dbcolsplittorows can now enumerate the output rows with "-E".

BUG FIX

dbcolmovingstats is more mathematically robust. Previously for some inputs and some platforms, floating point rounding could sometimes cause squareroots of negative numbers.

NEW

sqlselect_to_db converts the output of the MySQL or MarinaDB select comment into fsdb format.

INCOMPATIBLE CHANGE

dbfilediff now outputs the second row when doing sloppy numeric comparisons, to better support test suites.

2.52, 2014-11-03 Fixing the test suite for line number changes.
ENHANCEMENT

Test suites changes to be robust to exact line numbers of failures, since different Perl releases fail on different lines. <https://bugzilla.redhat.com/show_bug.cgi?id=1158380>

2.53, 2014-11-26 bug fixes and stability improvements to dbmapreduce
ENHANCEMENT

The dbfilediff how supports a "--quiet" option.

ENHANCEMENT

Better documention of dbpipeline_filter.

BUGFIX

Added groff-base and perl-podlators to the Fedora package spec. Fixes <https://bugzilla.redhat.com/show_bug.cgi?id=1163149>. (Also in package 2.52-2.)

BUGFIX

An important stability improvement to dbmapreduce. It, plus dbmultistats, and dbcolstats now support controlled parallelism with the "--pararallelism=N" option. They default to run with the number of available CPUs. dbmapreduce also moderates its level of parallelism. Previously it would create reducers as needed, causing CPU thrashing if reducers ran much slower than data production.

BUGFIX

The combination of dbmapreduce with dbrowenumerate now works as it should. (The obscure bug was an interaction with dbcolcreate with non-multi-key reducers that output their own key. dbmapreduce has too many useful corner cases.)

2.54, 2014-11-28 fix for the test suite to correct failing tests on not-my-platform
BUGFIX

Sigh, the test suite now has a test suite. Because, yes, I broke it, causing many incorrect failures at cpantesters. Now fixed.

2.55, 2015-01-05 many spelling fixes and dbcolmovingstats tests are more robust to different numeric precision
ENHANCEMENT

dbfilediff now can be extra quiet, as I continue to try to track down a numeric difference on FreeBSD AMD boxes.

ENHANCEMENT

dbcolmovingstats gave different test output (just reflecting rounding error) when stddev approaches zero. We now detect hand handle this case. See <https://rt.cpan.org/Public/Bug/Display.html?id=101220> and thanks to H. Merijn Brand for the bug report.

BUG FIX

Many, many spelling bugs found by H. Merijn Brand; thanks for the bug report.

INCOMPATBLE CHANGE

A number of programs had misspelled "separator" in "--fieldseparator" and "--columnseparator" options as "seperator". These are now correctly spelled.

2.56, 2015-02-03 fix against Getopt::Long-2.43’s stricter error checkign
BUG FIX

Internal argument parsing uses Getopt::Long, but mixed pass-through and <>. Bug reported by Petr Pisar at <https://bugzilla.redhat.com/show_bug.cgi?id=1188538>.a

BUG FIX

Added missing BuildRequires for "XML::Simple".

2.57, 2015-04-29 Minor changes, with better performance from dbmulitstats.
BUG FIX

dbfilecat now honors "--remove-inputs" (previously it didn’t). This omission meant that dbmapreduce (and dbmultistats) would accumulate files in /tmp when running. Bad news for inputs with 4M keys.

ENHANCMENT

dbmultistats should be faster with lots of small keys. dbcolstats now supports "-k" to get some of the functionality of dbmultistats (if data is pre-sorted and median/quartiles are not required).

dbfilecat now honors "--remove-inputs" (previously it didn’t). This omission meant that dbmapreduce (and dbmultistats) would accumulate files in /tmp when running. Bad news for inputs with 4M keys.

2.58, 2015-04-30 Bugfix in dbmerge
BUG FIX

Fixed a case where dbmerge suffered mojobake in endgame mode. This bug surfaced when dbsort was applied to large files (big enough to require merging) with unicode in them; the symptom was soemthing like:
Wide character in print at /usr/lib64/perl5/IO/Handle.pm line 420, < GEN12 > line 111.

2.59, 2016-09-01 Collect a few small bug fixes and documentation improvements.
BUG FIX

More IO is explicitly marked UTF-8 to avoid Perl’s tendency to mojibake on otherwise valid unicode input. This change helps html_table_to_db.

ENHANCEMENT

dbcolscorrelate now crossreferences dbcolsregression.

ENHANCEMENT

Documentation for dbrowdiff now clarifies that the default is baseline mode.

BUG FIX

dbjoin now propagates "-T" into the sorting process (if it is required). Thanks to Lan Wei for reporting this bug.

2.60, 2016-09-04 Adds support for hash joins.
ENHANCEMENT

dbjoin now supports hash joins with "-t lefthash" and "-t righthash". Hash joins cache a table in memory, but do not require that the other table be sorted. They are ideal when joining a large table against a small one.

2.61, 2016-09-05 Support left and right outer joins.
ENHANCEMENT

dbjoin now handles left and right outer joins with "-t left" and "-t right".

ENHANCEMENT

dbjoin hash joins are now selected with "-m lefthash" and "-m righthash" (not the shortlived "-t righthash" option). (Technically this change is incompatible with Fsdd-2.60, but no one but me ever used that version.)

2.62, 2016-11-29 A new yaml_to_db and other minor improvements.
ENHANCEMENT

Documentation for xml_to_db now includes sample output.

NEW

yaml_to_db converts a specific form of YAML to fsdb.

BUG FIX

The test suite now uses "diff -c -b" rather than "diff -cb" to make OpenBSD-5.9 happier, I hope.

ENHANCEMENT

Comments that log operations at the end of each file now do simple quoting of spaces. (It is not guaranteed to be fully shell-compliant.)

ENHANCEMENT

There is a new standard option, "--header", allowing one to specify an Fsdb header for inputs that lack it. Currently it is supported by dbcoldefine, dbrowuniq, dbmapreduce, dbmultistats, dbsort, dbpipeline.

ENHANCEMENT

dbfilepivot now allows the --possible-pivots option, and if it is provided processes the data in one pass.

ENHANCEMENT

dbroweval logs are now quoted.

2.63, 2017-02-03 Re-add some features supposedly in 2.62 but not, and add more --header options.
ENHANCEMENT

The option -j is now a synonym for --parallelism. (And several documention bugs about this option are fixed.)

ENHANCEMENT

Additional support for "--header" in dbcolmerge, dbcol, dbrow, and dbroweval.

BUG FIX

Version 2.62 was supposed to have this improvement, but did not (and now does): dbfilepivot now allows the --possible-pivots option, and if it is provided processes the data in one pass.

BUG FIX

Version 2.62 was supposed to have this improvement, but did not (and now does): dbroweval logs are now quoted.

2.64, 2017-11-20 several small bugfixes and enhancements
BUG FIX

In dbroweval, the "next row" option previously did not correctly set up "_last_fieldname". It now does.

ENHANCEMENT

The csv_to_db converter now has an optional "-F x" option to set the field separator.

ENHANCEMENT

Finally dbcolsplittocols has a "--header" option, and a new "-N" option to give the list of resulting output columns.

INCOMPATIBLE CHANGE

Now dbcolstats and dbmultistats produce no output (but a schema) when given no input but a schema. Previously they gave a null row of output. The "--output-on-no-input" and "--no-output-on-no-input" options can control this behavior.

2.65, 2018-02-16 Minor release, bug fix and -F option.
ENHANCEMENT

dbmultistats and dbmapreduce now both take a "-F x" option to set the field separator.

BUG FIX

Fixed missing "use Carp" in dbcolstats. Also went back and cleaned up all uses of "croak()". Thanks to Zefram for the bug report.

2.66, 2018-12-20 Critical bug fix in dbjoin.
BUG FIX

Removed old tests from MANIFEST. (Thanks to Hang Guo for reporting this bug.)

IMPROVEMENT

Errors for non-existing input files now include the bad filename (before: "cannot setup filehandle", now: "cannot open input: cannot open TEST/bad_filename").

BUG FIX

Hash joins with three identical rows were failing with the assertion failure "internal error: confused about overflow" due to a now-fixed bug.

2.67, 2019-07-10 add support for reading and writing hdfs
IMPROVEMENT

dbformmail now has an "mh" mechanism that writes messages to individual files (an mh-style mailbox).

BUG FIX

dbrow failed to include the Carp library, leading to fails on croak.

BUG FIX

Fixed dbjoin error message for an unsorted right stream was incorrect (it said left).

IMPROVEMENT

All Fsdb programs can now read from and write to HDFS, when files that start with "hdfs:" are given to -i and -o options.

2.68, 2019-09-19 All programs now support automatic decompression based on file extension.
IMPROVEMENT

The omitted-possible-error test case for dbfilepivot now has an altnerative output that I saw on some BSD-running systems (thanks to CPAN ).

IMPROVEMENT

dbmerge and dbmerge2 now support "--header". dbmerge2 now gives better error messages when presented the wrong number of inputs.

BUG FIX

dbsort now works with "--header" even when the file is big (due to fixes to dbmerge).

IMPROVEMENT

cvs_to_db now processes data with the "binary" option, allowing it to handle newlines embedded in quoted fields.

IMPROVEMENT

All programs now will transparently decompress input files, if they are listed as a filename as an input argument that extends with a standard extension (.gz, .bz2, and .xz).

2.69, 2019-11-22 a small bugfix in dbcolstats
BUG FIX

Filled in the the test case for autodecompress, which was missing for the 2.68 release.

ENHANCEMENT

The groff program is required for build, and the "Makefile.PL" fails if groff is missing at build time. Thanks to Chris Williams for suggesting this check, and the CPAN auto-building system for trying many platforms.

BUG FIX

The dbcolstats program had numerical instability that sometimes results in failing with a square-root of a negative number when many values varied right at the edge of floating-point precision. We now detect and report that case as 0 stddev. Thanks to Hang Guo for providing a test case.

2.70, 2020-11-12 Some small quality-of-life enhancements and corner-case bugfixes.
ENHANCEMENT

dbcol can now take an option "-a" to include all columns, allowing reordering of certain columns while passing the rest through.

ENHANCEMENT

dbrowuniq and dbmerge now buffer comments in a way that the last row of data output is no longer in the last block of comments. (The data is identical, but for humans looking at output, this change makes it less likely to lose the last row.)

BUG FIX

dbmultistats and dbpipeline documentation now indicates that they support "--header" (something they did since version 2.62 in 2016-11-29, but now documented.

ENHANCEMENT

dbcolcreate now supports "--header".

BUG FIX

Fixed several spelling errors in deprecated programs and removed information about the no-longer existing FreeBSD and MacOS ports. Thanks to Calvin Ardi for the patch.

BUG FIX

dbmerge now handles --xargs when only one file is provided (and passes the file through unchanged). It also throws a clean error with --xargs if zero files are provided. (To support dbmerge, dbcol now has an internal "--saveoutput" option.) Thanks to Yuri Pradkin for reporting the unhandled corner-case.

2.71, 2020-11-16 Fix a race condition breaking test suites.
BUG FIX

Suppress a race condition in dbcolmerge was sometimes throwing the error "Fsdb::Support::Freds: ending, but running process: dbmerge:xargs" in the dbmerge_0_xargs test case, on exit.

2.72, 2020-12-01 A small bug and a packaging improvement.
BUG FIX

dbcolhisto now handles the degenerate case where everything has the same value (previously it would throw "illegal division by zero").

ENHANCEMENT

The spec for Fedora now includes "make" as BuildRequires, something required for Fedora 34.

2.73, 2021-05-18 Updates dbcolpercentile with "--weighted", and with more ipv6.
ENHANCEMENT

dbcolpercentile now has a "--weighted" option.

ENHANCEMENT

The new Fsdb::Support::IPv6 package includes ipv6_normalize, ipv6_zeroize to rewrite ipv6 print addresses in IPv6 normal form, with a 0 in each 4-nybble field.

2.74, 2021-06-23 More ipv6.
ENHANCEMENT

Fsdb::Support::IPv6 package includes ipv6_fullhex to rewrite ipv6 print addresses as full, 128-bit hex values.

2.75, 2022-04-02 New type specifications in the schema to better support type conversions in python.
ENHANCEMENT

Add optional type specifications to the schema. Types are not used in Perl, but are relevant in Python and Go Fsdb bindings. Types use a subset of perl pack specifiers: c, s, l, q are signed 8, 16, 32, and 64-bit integers, f is a float, d is double float, a is utf-8 string, and &gt; and &lt; can force big or little endianness. The default type for everything is "a", that is, utf-8 strings. Thanks to Wes Hardaker for pushing to get this long-desired feature out the door; his Python bindings need types.

ENHANCEMENT

dbcol, dbcolcreate, dbcolcopylast, and dbcolrename now understand and propagate schema types. dbsort, dbjoin, dbmerge, dbmerge2 and dbfilepivot all take a new option "-t" to sort by type-inferred comparision, if a type is given.

ENHANCEMENT

dbcolstat, dbmultistats, and dbcolmovingstats now include type information in their output schema. (They assumes input variables are floats, not integers.)

ENHANCEMENT

Even more IPv6: the functions in Fsdb::Support::IPv6 package now support strings of hex digits as an alternate encoding for IP address (and they are already the output of ipv6_fullhex), and "ip_fullhex_to_normal" converts full hex-encoded IPv4 or IPv6 addresses to their "normal" form (dotted-quad or IPv6 printable format).

3.0, 2022-04-04 Complete type support and accordingly bump major version.

NEW

The major version number is now 3.0 to correspond to the addition of types (although they were actually added in 2.75). Old fsdb files are supported (Fsdb-3.0 is backwards compatible with databases), but older versions will confuse types in new files (new Fsdb files are not forward compatible with old versions).

ENHANCEMENT

Type specifications in a few more programs: dbcolhisto, dbcolscorrelate, dbcolsregression, dbcolstatscores, dbrowaccumulate, dbrowcount, dbrowdiff, dbrvstatdiff.

ENHANCEMENT

dbcolhisto now puts an empty value on any empty rows.

NEW

dbcoltype redefines column types, or clears them with the "-v" option.

AUTHOR

John Heidemann, "johnh AT isi DOT edu"

See "Contributors" for the many people who have contributed bug reports and fixes.

COPYRIGHT

Fsdb is Copyright (C) 1991-2022 by John Heidemann <johnh AT isi DOT edu>.

This program is free software; you can redistribute it and/or modify it under the terms of version 2 of the GNU General Public License as published by the Free Software Foundation.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY ; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

A copy of the GNU General Public License can be found in the file ’’ COPYING ’’.

COMMENTS and BUG REPORTS

Any comments about these programs should be sent to John Heidemann "johnh AT isi DOT edu".

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