Revise the "noquery" decision algorithm again. The index now must select

more than 150 rows on average, and the number of rows select must be enough
that it seems faster to do a full scan of the associated table.

FossilOrigin-Name: f516ef80a0ba87fa3b74da0fc899a7d14ad3de61fac6b467e36e7fa9fe76dcdf

diff --git a/manifest b/manifest
index 2da86ca734d3fa3c69f707c613905583a2c5b2e0..88f99ed4d8809426e2f82c50ce27766da0d0b3d5 100644 (file)
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Fix\san\sissue\sin\sthe\s"noquery"\sdecision\sin\sthe\sprevious\scheck-in.\s\sAlso\sadd\ncomments\sexplaining\sthe\salgorithm.
-D 2023-12-29T20:31:32.065
+C Revise\sthe\s"noquery"\sdecision\salgorithm\sagain.\s\sThe\sindex\snow\smust\sselect\nmore\sthan\s150\srows\son\saverage,\sand\sthe\snumber\sof\srows\sselect\smust\sbe\senough\nthat\sit\sseems\sfaster\sto\sdo\sa\sfull\sscan\sof\sthe\sassociated\stable.
+D 2023-12-29T21:07:00.789
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -670,7 +670,7 @@ F sqlite3.1 acdff36db796e2d00225b911d3047d580cd136547298435426ce9d40347973cc
 F sqlite3.pc.in 48fed132e7cb71ab676105d2a4dc77127d8c1f3a
 F sqlite_cfg.h.in baf2e409c63d4e7a765e17769b6ff17c5a82bbd9cbf1e284fd2e4cefaff3fcf2
 F src/alter.c 30c2333b8bb3af71e4eb9adeadee8aa20edb15917ed44b8422e5cd15f3dfcddc
-F src/analyze.c 6f88cfaf7e4de1cf9231b0c6c270b0f7d0d11fa0b33868c3890822757ba8df8d
+F src/analyze.c 0c4b43ba2e4e7db574c8af8e6cfdb09aff6a91a11caed821867c5b51708534d5
 F src/attach.c cc9d00d30da916ff656038211410ccf04ed784b7564639b9b61d1839ed69fd39
 F src/auth.c 19b7ccacae3dfba23fc6f1d0af68134fa216e9040e53b0681b4715445ea030b4
 F src/backup.c 5c97e8023aab1ce14a42387eb3ae00ba5a0644569e3476f38661fa6f824c3523
@@ -2156,8 +2156,8 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P e514d3fa83662aa19abefebdda5652e6adb0f0b5a75ad7ee9dd3d2d2c87e03c5
-R 5434c613e51a90ac2d4be4dfede8fa3d
+P 6aaa65adfc3b0c8e1ee7066de38d4385904c80da704b97440b0699fc78176ffa
+R 25c81b1dd9b3d0d849705539d9441d5c
 U drh
-Z afc1c4a983fea7e5c946a28458460117
+Z eef2167dc56c437be295ceda1d33c4be
 # Remove this line to create a well-formed Fossil manifest.

diff --git a/manifest.uuid b/manifest.uuid
index ed0edae5599e147112a3abdb4d4e6f49d212fd56..c4928fe2c8fefe0a26aa94a5fc6d92f27acb320d 100644 (file)
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-6aaa65adfc3b0c8e1ee7066de38d4385904c80da704b97440b0699fc78176ffa
\ No newline at end of file
+f516ef80a0ba87fa3b74da0fc899a7d14ad3de61fac6b467e36e7fa9fe76dcdf
\ No newline at end of file

diff --git a/src/analyze.c b/src/analyze.c
index d4c9806b1d97da9d87180e79d8e980ccc7c66229..1223a9f0679ecdd8ef4e3fcba26d5e31e361c6b5 100644 (file)
--- a/src/analyze.c
+++ b/src/analyze.c
@@ -891,12 +891,13 @@ static void statGet(
       sqlite3_str_appendf(&sStat, " %llu", iVal);
       assert( p->current.anEq[i] );
     }
-    if( iVal>=1000 && iVal*10>=nRow ){
-      /* If this index always matches 1000 or more rows even if all columns
-      ** match, and if the the number of rows matched is 1/10th or more of
-      ** the index, then this is a very low selectivity index.  Mark it as
-      ** "noquery" so that the query planner won't waste any time trying to
-      ** use it. */
+    if( iVal>=150 && iVal>=(nRow*10)/sqlite3LogEst(nRow) ){
+      /* If this index is likely to match 150 or more rows even if all columns
+      ** match, and if the the number of rows matched is such a large fraction
+      ** of the index that a full scan of the table would be faster than
+      ** doing a binary search for each row identified by the index,
+      ** then this is a very low selectivity index.  Mark it as "noquery"
+      ** so that the query planner won't waste any time trying to use it. */
       sqlite3_str_appendf(&sStat, " noquery");
     }
     sqlite3ResultStrAccum(context, &sStat);