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Increase performance of backout of dead record version (or undo of just created primary record version) when backversions chain is too long [CORE4935] #5226

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firebird-issue-importer opened this issue Sep 17, 2015 · 4 comments

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@firebird-issue-importer

Submitted by: @hvlad

Function list_staying() used in backout and undo processes have complexity O(N^2), where N is the number of back versions.

There is a way to reduce complexity down to O(N) in most cases. Specifically - when current transaction (which does backout
or undo) already own the record (i.e. primary record version is marked by current transaction) there is guarantee that no other
transaction will try to backout\undo the record.

Another improvement is to cut and cleanup tail of the back-versions chain at point where it is legal

Commits: f7e248c FirebirdSQL/fbt-repository@886459f

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firebird-issue-importer commented Sep 17, 2015

Modified by: @hvlad

assignee: Vlad Khorsun [ hvlad ]

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firebird-issue-importer commented Sep 17, 2015

Modified by: @hvlad

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

resolution: Fixed [ 1 ]

Fix Version: 3.0 RC 1 [ 10584 ]

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firebird-issue-importer commented Sep 23, 2015

Modified by: @pcisar

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

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firebird-issue-importer commented Oct 8, 2015

Modified by: @pavel-zotov

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

QA Status: No test => Cannot be tested

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