RandomQueryGeneratorFiltering

Table of Contents Filtering queries The .ff file Applying filtering Forcing MySQL to be ANSI-compatible

Filtering queries

Sometimes it is necessary to filter out certain queries from the sequence of generated queries before they are even executed. For example, a known crashing bug early in the test would prevent further bugs from being discovered down the line.

The .ff file

Which queries to be filtered out is controlled by a .ff file that contains a list of individual rules to be applied. Each rule has a name and can be either a regular expression, a subroutine, or a literal string. For example

 $rules = {
         'test_regexp'   => qr{update}si,
         'test_string'   => 'DELETE FROM `DD` WHERE `time_nokey` < 0 LIMIT 4',
         'test_sub'      => sub { m{insert}sio }
 };

The first rule is a regular expression which will be applied over each query individually. Note that SQL elements such as ( and . have special meaning inside regular expressions, so must be escaped with a \

The second rule is a string literal, which must match completely and exactly for the query to be filtered. Use a regexp if you want more flexible or partial matches.

The final rule is a subroutine, which is called with $_ and $_[0] set to the query in question. If the routine returns true, the query will be skipped.

Applying filtering

Filtering can be applied by passing the name of the .ff file to gentest.pl or runall.pl with the --filter parameter. Filtering is not applied during the data generation phase, e.g. to gendata.pl.

For example, this command-line:

 $ perl runall.pl \
   --basedir=/build/bzr/azalea-bugfixing/\
   --grammar=conf/example.yy \
   --threads=1 \
   --queries=10 \
   --filter=conf/example.ff

produces the following output:

 # 13:33:45 Loaded 3 filtering rules from 'conf/example.ff'
 ...
 # 13:33:45 Query: INSERT INTO `C` ( `datetime_key` ) VALUES ( 3 ) filtered out by code rule test_sub
 ...
 # 13:33:45 Query: DELETE FROM `DD` WHERE `time_nokey` < 0 LIMIT 4 filtered out by literal rule test_string.
 ...
 # 13:33:45 Query: INSERT INTO `E` ( `datetime_key` ) VALUES ( 4 ) filtered out by code rule test_sub

Forcing MySQL to be ANSI-compatible

The Filtering mechanism can be used to remove certain non-ANSI queries from the query stream so that the queries can be executed by non-MySQL databases. For example:

 'limit'   => qr{limit}si

would remove all queries containing LIMIT which is not a standard construct.

Category:RandomQueryGenerator