From: drh <drh@noemail.net>
Date: Wed, 30 Sep 2020 18:06:51 +0000 (+0000)
Subject: Improved query optimization for multi-column indexes where the second or
X-Git-Tag: version-3.34.0~82
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=fad4dd0fd1826c08f3f04c81b77d51dcb7f1c661;p=thirdparty%2Fsqlite.git

Improved query optimization for multi-column indexes where the second or
later columns are constrained by an IN operator and the earlier index columns
limit the search to a small number of rows.  Use the new OP_SeekScan opcode
which does scanning of the relevant range of the index but gives up and
falls back to doing a seek if the number of rows scanned grows to large,
in order to guard against pathological cases where the estimated number
of rows to be scanned is far too small.

FossilOrigin-Name: 4a43430fd23f88352c33b29c4c105b72f6dc821f94bf362040c41a1648c402e5
---

fad4dd0fd1826c08f3f04c81b77d51dcb7f1c661
diff --cc manifest
index 5d4357f4dc,59691be9f5..c14de66d65
--- a/manifest
+++ b/manifest
@@@ -1,5 -1,5 +1,5 @@@
- C Back\sout\sthe\sincorrect\soptimization\sof\scheck-in\s[e51ecadcbdef5ce6]\sas\nticket\s[5c4e7aa793943803]\sreports\sa\scase\swhere\sthe\soptimization\sdoes\snot\nwork.
- D 2020-09-30T17:32:22.269
 -C For\sthe\sOP_SeekScan\sopcode,\sadjust\sthe\snumber\sof\ssteps\srun\sbefore\sgiving\nup\sbased\son\sthe\sestimated\snumber\sof\scomparisons\sneeded\sto\sperform\sa\sseek.
 -D 2020-09-30T18:03:22.696
++C Improved\squery\soptimization\sfor\smulti-column\sindexes\swhere\sthe\ssecond\sor\nlater\scolumns\sare\sconstrained\sby\san\sIN\soperator\sand\sthe\searlier\sindex\scolumns\nlimit\sthe\ssearch\sto\sa\ssmall\snumber\sof\srows.\s\sUse\sthe\snew\sOP_SeekScan\sopcode\nwhich\sdoes\sscanning\sof\sthe\srelevant\srange\sof\sthe\sindex\sbut\sgives\sup\sand\nfalls\sback\sto\sdoing\sa\sseek\sif\sthe\snumber\sof\srows\sscanned\sgrows\sto\slarge,\nin\sorder\sto\sguard\sagainst\spathological\scases\swhere\sthe\sestimated\snumber\nof\srows\sto\sbe\sscanned\sis\sfar\stoo\ssmall.
++D 2020-09-30T18:06:51.119
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diff --cc manifest.uuid
index 9cb067398d,42e169af85..245640b3fd
--- a/manifest.uuid
+++ b/manifest.uuid
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