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pgsql: Improve planning of btree index scans using ScalarArrayOpExpr qu 4+ messages / 1 participants [nested] [flat]
* pgsql: Improve planning of btree index scans using ScalarArrayOpExpr qu @ 2014-10-26 20:12 Tom Lane <tgl@sss.pgh.pa.us> 0 siblings, 0 replies; 4+ messages in thread From: Tom Lane @ 2014-10-26 20:12 UTC (permalink / raw) To: pgsql-committers Improve planning of btree index scans using ScalarArrayOpExpr quals. Since we taught btree to handle ScalarArrayOpExpr quals natively (commit 9e8da0f75731aaa7605cf4656c21ea09e84d2eb1), the planner has always included ScalarArrayOpExpr quals in index conditions if possible. However, if the qual is for a non-first index column, this could result in an inferior plan because we can no longer take advantage of index ordering (cf. commit 807a40c551dd30c8dd5a0b3bd82f5bbb1e7fd285). It can be better to omit the ScalarArrayOpExpr qual from the index condition and let it be done as a filter, so that the output doesn't need to get sorted. Indeed, this is true for the query introduced as a test case by the latter commit. To fix, restructure get_index_paths and build_index_paths so that we consider paths both with and without ScalarArrayOpExpr quals in non-first index columns. Redesign the API of build_index_paths so that it reports what it found, saving useless second or third calls. Report and patch by Andrew Gierth (though rather heavily modified by me). Back-patch to 9.2 where this code was introduced, since the issue can result in significant performance regressions compared to plans produced by 9.1 and earlier. Branch ------ master Details ------- http://git.postgresql.org/pg/commitdiff/a4523c5aa5349510ddb74abddc416add2536ec3d Modified Files -------------- src/backend/optimizer/path/indxpath.c | 116 ++++++++++++++++++---------- src/test/regress/expected/create_index.out | 24 +++++- src/test/regress/sql/create_index.sql | 13 ++++ 3 files changed, 112 insertions(+), 41 deletions(-) -- Sent via pgsql-committers mailing list (pgsql-committers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-committers ^ permalink raw reply [nested|flat] 4+ messages in thread
* pgsql: Improve planning of btree index scans using ScalarArrayOpExpr qu @ 2014-10-26 20:12 Tom Lane <tgl@sss.pgh.pa.us> 0 siblings, 0 replies; 4+ messages in thread From: Tom Lane @ 2014-10-26 20:12 UTC (permalink / raw) To: pgsql-committers Improve planning of btree index scans using ScalarArrayOpExpr quals. Since we taught btree to handle ScalarArrayOpExpr quals natively (commit 9e8da0f75731aaa7605cf4656c21ea09e84d2eb1), the planner has always included ScalarArrayOpExpr quals in index conditions if possible. However, if the qual is for a non-first index column, this could result in an inferior plan because we can no longer take advantage of index ordering (cf. commit 807a40c551dd30c8dd5a0b3bd82f5bbb1e7fd285). It can be better to omit the ScalarArrayOpExpr qual from the index condition and let it be done as a filter, so that the output doesn't need to get sorted. Indeed, this is true for the query introduced as a test case by the latter commit. To fix, restructure get_index_paths and build_index_paths so that we consider paths both with and without ScalarArrayOpExpr quals in non-first index columns. Redesign the API of build_index_paths so that it reports what it found, saving useless second or third calls. Report and patch by Andrew Gierth (though rather heavily modified by me). Back-patch to 9.2 where this code was introduced, since the issue can result in significant performance regressions compared to plans produced by 9.1 and earlier. Branch ------ REL9_4_STABLE Details ------- http://git.postgresql.org/pg/commitdiff/859e2b9dd4de94ef9a9ad34da3e39572e4f1d66f Modified Files -------------- src/backend/optimizer/path/indxpath.c | 116 ++++++++++++++++++---------- src/test/regress/expected/create_index.out | 24 +++++- src/test/regress/sql/create_index.sql | 13 ++++ 3 files changed, 112 insertions(+), 41 deletions(-) -- Sent via pgsql-committers mailing list (pgsql-committers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-committers ^ permalink raw reply [nested|flat] 4+ messages in thread
* pgsql: Improve planning of btree index scans using ScalarArrayOpExpr qu @ 2014-10-26 20:12 Tom Lane <tgl@sss.pgh.pa.us> 0 siblings, 0 replies; 4+ messages in thread From: Tom Lane @ 2014-10-26 20:12 UTC (permalink / raw) To: pgsql-committers Improve planning of btree index scans using ScalarArrayOpExpr quals. Since we taught btree to handle ScalarArrayOpExpr quals natively (commit 9e8da0f75731aaa7605cf4656c21ea09e84d2eb1), the planner has always included ScalarArrayOpExpr quals in index conditions if possible. However, if the qual is for a non-first index column, this could result in an inferior plan because we can no longer take advantage of index ordering (cf. commit 807a40c551dd30c8dd5a0b3bd82f5bbb1e7fd285). It can be better to omit the ScalarArrayOpExpr qual from the index condition and let it be done as a filter, so that the output doesn't need to get sorted. Indeed, this is true for the query introduced as a test case by the latter commit. To fix, restructure get_index_paths and build_index_paths so that we consider paths both with and without ScalarArrayOpExpr quals in non-first index columns. Redesign the API of build_index_paths so that it reports what it found, saving useless second or third calls. Report and patch by Andrew Gierth (though rather heavily modified by me). Back-patch to 9.2 where this code was introduced, since the issue can result in significant performance regressions compared to plans produced by 9.1 and earlier. Branch ------ REL9_3_STABLE Details ------- http://git.postgresql.org/pg/commitdiff/f6abf8f08ac36825e3cbcaf6ef923822e65877f4 Modified Files -------------- src/backend/optimizer/path/indxpath.c | 116 ++++++++++++++++++---------- src/test/regress/expected/create_index.out | 24 +++++- src/test/regress/sql/create_index.sql | 13 ++++ 3 files changed, 112 insertions(+), 41 deletions(-) -- Sent via pgsql-committers mailing list (pgsql-committers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-committers ^ permalink raw reply [nested|flat] 4+ messages in thread
* pgsql: Improve planning of btree index scans using ScalarArrayOpExpr qu @ 2014-10-26 20:12 Tom Lane <tgl@sss.pgh.pa.us> 0 siblings, 0 replies; 4+ messages in thread From: Tom Lane @ 2014-10-26 20:12 UTC (permalink / raw) To: pgsql-committers Improve planning of btree index scans using ScalarArrayOpExpr quals. Since we taught btree to handle ScalarArrayOpExpr quals natively (commit 9e8da0f75731aaa7605cf4656c21ea09e84d2eb1), the planner has always included ScalarArrayOpExpr quals in index conditions if possible. However, if the qual is for a non-first index column, this could result in an inferior plan because we can no longer take advantage of index ordering (cf. commit 807a40c551dd30c8dd5a0b3bd82f5bbb1e7fd285). It can be better to omit the ScalarArrayOpExpr qual from the index condition and let it be done as a filter, so that the output doesn't need to get sorted. Indeed, this is true for the query introduced as a test case by the latter commit. To fix, restructure get_index_paths and build_index_paths so that we consider paths both with and without ScalarArrayOpExpr quals in non-first index columns. Redesign the API of build_index_paths so that it reports what it found, saving useless second or third calls. Report and patch by Andrew Gierth (though rather heavily modified by me). Back-patch to 9.2 where this code was introduced, since the issue can result in significant performance regressions compared to plans produced by 9.1 and earlier. Branch ------ REL9_2_STABLE Details ------- http://git.postgresql.org/pg/commitdiff/4586572d789952f2be64faaa2c3e00e549162aec Modified Files -------------- src/backend/optimizer/path/indxpath.c | 116 ++++++++++++++++++---------- src/test/regress/expected/create_index.out | 24 +++++- src/test/regress/sql/create_index.sql | 13 ++++ 3 files changed, 112 insertions(+), 41 deletions(-) -- Sent via pgsql-committers mailing list (pgsql-committers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-committers ^ permalink raw reply [nested|flat] 4+ messages in thread
end of thread, other threads:[~2014-10-26 20:12 UTC | newest] Thread overview: 4+ messages (download: mbox mbox.gz follow: Atom feed) -- links below jump to the message on this page -- 2014-10-26 20:12 pgsql: Improve planning of btree index scans using ScalarArrayOpExpr qu Tom Lane <tgl@sss.pgh.pa.us> 2014-10-26 20:12 pgsql: Improve planning of btree index scans using ScalarArrayOpExpr qu Tom Lane <tgl@sss.pgh.pa.us> 2014-10-26 20:12 pgsql: Improve planning of btree index scans using ScalarArrayOpExpr qu Tom Lane <tgl@sss.pgh.pa.us> 2014-10-26 20:12 pgsql: Improve planning of btree index scans using ScalarArrayOpExpr qu Tom Lane <tgl@sss.pgh.pa.us>
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