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Estimate the actual record compression ratio in the optimizer [CORE3295] #3663

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firebird-issue-importer opened this issue Dec 28, 2010 · 6 comments

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Submitted by: @dyemanov

Currently, when the table cardinality (number of records) gets estimated, all records are considered to be compressed twice in size (hardcoded compression ratio of 0.5). It would be better to have some estimation (even rough) of the actual compression ratio, because in practice it can differ much from the expected value. This becomes more important starting with versions 2.1.4 and 2.5.0 that have the join cost more depending on the proper cardinality estimations than in prior versions.

Commits: 11297a0 b5dc562 f19f33a d81d678

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firebird-issue-importer commented Dec 28, 2010

Modified by: @dyemanov

security: Developers [ 10012 ] =>

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firebird-issue-importer commented Dec 28, 2010

Modified by: @dyemanov

assignee: Dmitry Yemanov [ dimitr ]

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firebird-issue-importer commented Dec 28, 2010

Modified by: @dyemanov

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

resolution: Fixed [ 1 ]

Fix Version: 2.1.4 [ 10361 ]

Fix Version: 2.5.1 [ 10333 ]

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firebird-issue-importer commented Feb 4, 2011

Modified by: @pcisar

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

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firebird-issue-importer commented Jan 18, 2016

Modified by: @pavel-zotov

QA Status: No test

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firebird-issue-importer commented Nov 28, 2017

Modified by: @dyemanov

Fix Version: 3.0.3 [ 10810 ]

Fix Version: 4.0 Beta 1 [ 10750 ]

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