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Suboptimal join plan if there are selective non-indexed predicates involved [CORE2078] #2513

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firebird-issue-importer opened this issue Sep 12, 2008 · 10 comments

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@firebird-issue-importer

Submitted by: @dyemanov

Attachments:
TEST1.rar

The optimizer always had some trivial heuristics to estimate the effective stream selectivity even if no indices could be used for the retrieval. But this code hasn't been migrated into the new (post-ODS10) optimizer logic, thus causing ineffective join orders chosen for the cases when non-indexed predicates may noticeably truncate the leading stream output.

Commits: a7b6702 a082a6f 4b79215 cd08735 0c9b728 ddb3e8f

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

#⁠#⁠#⁠ ACHTUNG #⁠#⁠#⁠

1) Since time of commit (3.0.0.31836, 15-May-2015) passed on only on SuperClassic. Failed on SuperServer. How could it be if test isn`t related to arch. specifics ?! Last letter to dimitr: 16-may-2015 13:55, subject: 'fix core-2078';

2) Representation of double precision values from rdb$indices.rdb$statistics differs on Linux vs Windows in 15th digit. Decided to change out-argument of procedure that does SET STATISTICS INDEX ... to numeric(12, 10);

3) Seems that some investigations should be in optimizer due to poor predictable PLAN when change initial values of rows number in tables.

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@firebird-issue-importer firebird-issue-importer commented Sep 12, 2008

Modified by: @dyemanov

assignee: Dmitry Yemanov [ dimitr ]

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@firebird-issue-importer firebird-issue-importer commented Sep 12, 2008

Modified by: @dyemanov

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

Fix Version: 2.5 Beta 1 [ 10251 ]

Fix Version: 2.1.2 [ 10270 ]

Fix Version: 2.0.5 [ 10222 ]

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@firebird-issue-importer firebird-issue-importer commented Sep 12, 2008

Commented by: @dyemanov

Archived database backup is attached. Sorry for the RAR format, but ZIP cannot compress it into less than 10MB enforced by Jira.

Test query:

select count(*)
from small_table sa
join big_table pg on pg.id_small = sa.id_small
join medium_table psg on psg.id_medium = pg.id_medium
where sa.id_fk_1 = 0 -- selective non-indexed boolean

Auto-generated BAD plan:
PLAN JOIN (PSG NATURAL, PG INDEX (BIG_TABLE_IDX2), SA INDEX (SMALL_TABLE_IDX1))
Execute time = 10s

Expected GOOD plan:
PLAN JOIN (SA NATURAL, PG INDEX (BIG_TABLE_IDX1), PSG INDEX (PK_MEDIUM_TABLE))
Execute time = 1.5s

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@firebird-issue-importer firebird-issue-importer commented Sep 12, 2008

Modified by: @dyemanov

Attachment: TEST1.rar [ 11050 ]

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@firebird-issue-importer firebird-issue-importer commented Sep 12, 2008

Modified by: @dyemanov

environment: Any => Any, ODS11 and higher only

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@firebird-issue-importer firebird-issue-importer commented Sep 12, 2008

Modified by: @dyemanov

status: Open [ 1 ] => In Progress [ 3 ]

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@firebird-issue-importer firebird-issue-importer commented Oct 8, 2008

Modified by: @dyemanov

status: In Progress [ 3 ] => Open [ 1 ]

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@firebird-issue-importer firebird-issue-importer commented Oct 8, 2008

Modified by: @dyemanov

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

resolution: Fixed [ 1 ]

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@firebird-issue-importer firebird-issue-importer commented Feb 23, 2011

Modified by: @pcisar

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

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@firebird-issue-importer firebird-issue-importer commented May 27, 2015

Modified by: @pavel-zotov

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

QA Status: Done with caveats

Test Details: #⁠#⁠#⁠ ACHTUNG #⁠#⁠#⁠

1) Since time of commit (3.0.0.31836, 15-May-2015) passed on only on SuperClassic. Failed on SuperServer. How could it be if test isn`t related to arch. specifics ?! Last letter to dimitr: 16-may-2015 13:55, subject: 'fix core-2078';

2) Representation of double precision values from rdb$indices.rdb$statistics differs on Linux vs Windows in 15th digit. Decided to change out-argument of procedure that does SET STATISTICS INDEX ... to numeric(12, 10);

3) Seems that some investigations should be in optimizer due to poor predictable PLAN when change initial values of rows number in tables.

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