Submitted by: @hvlad

Prepare trace configuration file such as

<database>
enabled true

#⁠include\_filter 
exclude\_filter   %no\_trace%

log\_connections true
log\_transactions true
log\_statement\_finish true

print\_plan true
print\_perf true

time\_threshold 0

</database>

and start trace session using this config.

In the second console run isql and attach to any database.

isql :
SQL> select 1 from rdb$database;

CONSTANT

============
1

SQL> commit;

corresponding trace output :

2010-03-23T21:52:18.0500 (404:035CC440) START_TRANSACTION
F:\FB2\FB25.TRACE\TEMP\WIN32\RELEASE\FIREBIRD\BIN\A.FDB (ATT_24, SYSDBA:NONE, XNET:W2K3-X64)
F:\FB2\fb25.trace\temp\Win32\Release\firebird\bin\isql.exe:1456
(TRA_53, CONCURRENCY | WAIT | READ_WRITE)

2010-03-23T21:52:18.0500 (404:035CC440) START_TRANSACTION
F:\FB2\FB25.TRACE\TEMP\WIN32\RELEASE\FIREBIRD\BIN\A.FDB (ATT_24, SYSDBA:NONE, XNET:W2K3-X64)
F:\FB2\fb25.trace\temp\Win32\Release\firebird\bin\isql.exe:1456
(TRA_54, READ_COMMITTED | NO_REC_VERSION | WAIT | READ_WRITE)

2010-03-23T21:52:18.0660 (404:035CC440) EXECUTE_STATEMENT_FINISH
F:\FB2\FB25.TRACE\TEMP\WIN32\RELEASE\FIREBIRD\BIN\A.FDB (ATT_24, SYSDBA:NONE, XNET:W2K3-X64)
F:\FB2\fb25.trace\temp\Win32\Release\firebird\bin\isql.exe:1456
(TRA_53, CONCURRENCY | WAIT | READ_WRITE)

Statement 138:
-------------------------------------------------------------------------------
select 1 from rdb$database
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
PLAN (RDB$DATABASE NATURAL)
1 records fetched
0 ms, 13 fetch(es)

Table Natural Index Update Insert Delete Backout Purge Expunge
***************************************************************************************************************
RDB$DATABASE 1
RDB$CHARACTER_SETS 1
RDB$COLLATIONS 1

2010-03-23T21:52:24.6600 (404:035CC440) COMMIT_TRANSACTION
F:\FB2\FB25.TRACE\TEMP\WIN32\RELEASE\FIREBIRD\BIN\A.FDB (ATT_24, SYSDBA:NONE, XNET:W2K3-X64)
F:\FB2\fb25.trace\temp\Win32\Release\firebird\bin\isql.exe:1456
(TRA_53, CONCURRENCY | WAIT | READ_WRITE)
1 ms, 1 read(s), 1 write(s), 1 fetch(es), 1 mark(s)

2010-03-23T21:52:24.6600 (404:035CC440) COMMIT_TRANSACTION
F:\FB2\FB25.TRACE\TEMP\WIN32\RELEASE\FIREBIRD\BIN\A.FDB (ATT_24, SYSDBA:NONE, XNET:W2K3-X64)
F:\FB2\fb25.trace\temp\Win32\Release\firebird\bin\isql.exe:1456
(TRA_54, READ_COMMITTED | NO_REC_VERSION | WAIT | READ_WRITE)
0 ms, 1 read(s), 1 write(s), 1 fetch(es), 1 mark(s)

This is as expectd. Now issue sql statement which should be filtered out by regular expression %no_trace% :

SQL> select 2 from rdb$database /* no_trace*/;

CONSTANT

============
2

SQL> commit;

Corresponding trace output :

2010-03-23T21:52:31.2380 (404:035CC440) START_TRANSACTION
F:\FB2\FB25.TRACE\TEMP\WIN32\RELEASE\FIREBIRD\BIN\A.FDB (ATT_24, SYSDBA:NONE, XNET:W2K3-X64)
F:\FB2\fb25.trace\temp\Win32\Release\firebird\bin\isql.exe:1456
(TRA_55, CONCURRENCY | WAIT | READ_WRITE)

2010-03-23T21:52:31.3320 (404:035CC440) START_TRANSACTION
F:\FB2\FB25.TRACE\TEMP\WIN32\RELEASE\FIREBIRD\BIN\A.FDB (ATT_24, SYSDBA:NONE, XNET:W2K3-X64)
F:\FB2\fb25.trace\temp\Win32\Release\firebird\bin\isql.exe:1456
(TRA_56, READ_COMMITTED | NO_REC_VERSION | WAIT | READ_WRITE)

2010-03-23T21:52:38.5500 (404:035CC440) COMMIT_TRANSACTION
F:\FB2\FB25.TRACE\TEMP\WIN32\RELEASE\FIREBIRD\BIN\A.FDB (ATT_24, SYSDBA:NONE, XNET:W2K3-X64)
F:\FB2\fb25.trace\temp\Win32\Release\firebird\bin\isql.exe:1456
(TRA_55, CONCURRENCY | WAIT | READ_WRITE)
1 records fetched
0 ms, 5 fetch(es)

Table Natural Index Update Insert Delete Backout Purge Expunge
***************************************************************************************************************
RDB$DATABASE 1
1 ms, 1 read(s), 1 write(s), 1 fetch(es), 1 mark(s)

2010-03-23T21:52:38.5500 (404:035CC440) COMMIT_TRANSACTION
F:\FB2\FB25.TRACE\TEMP\WIN32\RELEASE\FIREBIRD\BIN\A.FDB (ATT_24, SYSDBA:NONE, XNET:W2K3-X64)
F:\FB2\fb25.trace\temp\Win32\Release\firebird\bin\isql.exe:1456
(TRA_56, READ_COMMITTED | NO_REC_VERSION | WAIT | READ_WRITE)
0 ms, 1 read(s), 1 write(s), 1 fetch(es), 1 mark(s)

Note lines

1 records fetched
0 ms, 5 fetch(es)

Table Natural Index Update Insert Delete Backout Purge Expunge
***************************************************************************************************************
RDB$DATABASE 1

after first COMMIT_TRANSACTION event. They are corresponds to the filtered out SQL statement and should not be put into trace output.

Commits: 9685411 035e567