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Execution of SET STATISTICS INDEX statement could block or slow execution of concurrent attachments [CORE4215] #4540
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Modified by: @hvladassignee: Vlad Khorsun [ hvlad ] |
Modified by: @hvladdescription: BTR_selectivity() walks the whole leaf level of given index b-tree to calculate index selectivity. => BTR_selectivity() walks the whole leaf level of given index b-tree to calculate index selectivity. summary: Execution of SET STATISTICS INDEX statement could block execution of concurrent attachments => Execution of SET STATISTICS INDEX statement could block or slow execution of concurrent attachments |
Commented by: Siva Ramanathan (s2ramana) This is a serious issue for any 24x7 sites using Firebird. |
Commented by: @hvlad Siva, |
Commented by: Siva Ramanathan (s2ramana) Vlad, IBPhoenix is preparing a build for us with the fix. We should be receiving the build any day now. Once we receive the build, we will test it out and give our feedback. Regards, |
Commented by: @paulbeach Siva, Vlad was the developer we worked with on this issue. Your current build has the fix for this issue. The new build addresses another problem. Paul |
Commented by: Siva Ramanathan (s2ramana) Paul, Thanks for the update. Regards, |
Commented by: @hvlad Any feedback ? |
Commented by: Siva Ramanathan (s2ramana) Vlad, your fix appears to be working correctly. We have not noticed this issue after applying the fix. Regards, |
Commented by: @hvlad Siva, will close it as fixed, thanks |
Modified by: @hvladstatus: Open [ 1 ] => Resolved [ 5 ] resolution: Fixed [ 1 ] Fix Version: 2.5.3 [ 10461 ] Fix Version: 3.0 Alpha 2 [ 10560 ] |
Modified by: @pcisarstatus: Resolved [ 5 ] => Closed [ 6 ] |
Modified by: @pavel-zotovstatus: Closed [ 6 ] => Closed [ 6 ] QA Status: No test => Deferred Test Details: Creation of huge table on the fly is not allowed - we can not waste time for this while all tests running. |
Submitted by: @hvlad
Votes: 2
BTR_selectivity() walks the whole leaf level of given index b-tree to calculate index selectivity.
During whole process rescheduling points in the engine happens only at disk IO operations.
Therefore concurrent attachment's AST requests such as page lock requests, monitoring,
cancellation, etc could wait too long.
Commits: dd5b5af cfa78a3 FirebirdSQL/fbt-repository@648fe03 FirebirdSQL/fbt-repository@d0d0174
====== Test Details ======
Creation of huge table on the fly is not allowed - we can not waste time for this while all tests running.
Database with huge table should be preliminary created (seperately for every ODS) and committed on test running host.
It seems to me that this is also undesirable.
Waiting for other suggestions how to implement such test.
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