From: drh <drh@noemail.net>
Date: Fri, 14 Apr 2017 17:30:43 +0000 (+0000)
Subject: When doing a DISTINCT query using an index, try to use the index to skip ahead
X-Git-Tag: version-3.19.0~59
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=1a17b44231b0116fcd065043ac722443bc2f4f7f;p=thirdparty%2Fsqlite.git

When doing a DISTINCT query using an index, try to use the index to skip ahead
to the next distinct element, rather than doing a full scan of the index.
(This is the "skip-ahead-distinct" optimization.)

FossilOrigin-Name: f489b5bb6b35665befdd411c2c55df5258e83cba265d8c4427ba22529cf882a4
---

1a17b44231b0116fcd065043ac722443bc2f4f7f
diff --cc manifest
index 6a6c5eab16,91fde0d998..658ad9ece0
--- a/manifest
+++ b/manifest
@@@ -1,8 -1,8 +1,8 @@@
- C Make\sUSE_FULLWARN=1\sthe\sdefault\sfor\sMSVC\sand\sfix\sharmless\scompiler\swarnings.
- D 2017-04-14T14:50:34.600
 -C Fix\sa\scouple\sof\sunreachable\sbranches.
 -D 2017-04-14T00:45:51.643
++C When\sdoing\sa\sDISTINCT\squery\susing\san\sindex,\stry\sto\suse\sthe\sindex\sto\sskip\sahead\nto\sthe\snext\sdistinct\selement,\srather\sthan\sdoing\sa\sfull\sscan\sof\sthe\sindex.\n(This\sis\sthe\s"skip-ahead-distinct"\soptimization.)
++D 2017-04-14T17:30:43.741
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 -F Makefile.msc a4c0613a18663bda56d8cf76079ab6590a7c3602e54befb4bbdef76bcaa38b6a
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  F README.md 2b15fae33852f2f53996774c21fb41e1d94181c4401a0e43ac93e11f2cc901b9
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  F aclocal.m4 a5c22d164aff7ed549d53a90fa56d56955281f50
@@@ -1571,7 -1572,7 +1572,8 @@@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a9
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+ U drh
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++Z 6edb0fabfc88ce2a863c335cf5598131
diff --cc manifest.uuid
index 39cfc39f28,bf75741857..dedaf39dc7
--- a/manifest.uuid
+++ b/manifest.uuid
@@@ -1,1 -1,1 +1,1 @@@
- 6bf673767b8e5cedef1acff795cbe524fab8db2525c06424db4e038934a33936
 -1aa0ea8db7580aff8bed2f78117ed50019e5545cef48cab782f512a2599fd0c5
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