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Rare segfault when preparing request working with a table with triggers [CORE5428] #5700

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firebird-issue-importer opened this issue Dec 25, 2016 · 5 comments

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@firebird-issue-importer

Submitted by: @AlexPeshkoff

This old and rarely happening bug happens when structure of a table with triggers is modified (DDL) when other attachment is preparing request working with that table. AST by itself does not cause any harm to data structures but rescan of table's metadata (which happens on any call to metadata cache for given table) drops old triggers description and creates new one. But in some cases pointers to old triggers are cached by request compiler and next use of them makes classic server process die.

Commits: 431b33b 0ca6c0d f88dded

====== Test Details ======

Significant (and artificial) slowdown in FB engine is required for reproducing this issue.
There are two tests for check FB stability while applying DDL under strong DML workload, but both of them did not produce any crash.
May be these tests will be added into fbt-repo but I will do it later (after further discuss with Alex).

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firebird-issue-importer commented Dec 25, 2016

Modified by: @AlexPeshkoff

assignee: Alexander Peshkov [ alexpeshkoff ]

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firebird-issue-importer commented Dec 25, 2016

Commented by: @AlexPeshkoff

I doubt it makes sense to have a test for this - I had to add artificial delays to cmp.cpp in order to reproduce an issue in a stable way.

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firebird-issue-importer commented Dec 25, 2016

Modified by: @AlexPeshkoff

status: Open [ 1 ] => Resolved [ 5 ]

resolution: Fixed [ 1 ]

Fix Version: 3.0.2 [ 10785 ]

Fix Version: 4.0 Alpha 1 [ 10731 ]

Fix Version: 2.5.7 [ 10770 ]

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firebird-issue-importer commented Dec 26, 2016

Modified by: @pavel-zotov

status: Resolved [ 5 ] => Resolved [ 5 ]

QA Status: No test => Cannot be tested

Test Details: Significant (and artificial) slowdown in FB engine is required for reproducing this issue.
There are two tests for check FB stability while applying DDL under strong DML workload, but both of them did not produce any crash.
May be these tests will be added into fbt-repo but I will do it later (after further discuss with Alex).

Test Specifics: [Architecture (SS/CS) specific]

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firebird-issue-importer commented Dec 26, 2016

Modified by: @pavel-zotov

status: Resolved [ 5 ] => Closed [ 6 ]

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