From: drh <>
Date: Mon, 5 Dec 2022 02:42:30 +0000 (+0000)
Subject: Use the smaller estimated row size for searching IPK tables, but use the
X-Git-Tag: version-3.41.0~312^2
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=refs%2Fheads%2Fqp-tuning;p=thirdparty%2Fsqlite.git

Use the smaller estimated row size for searching IPK tables, but use the
original larger row size estimate for scanning, since the leaves can have large
rows.

FossilOrigin-Name: df3818997b822743ac407dde45c5fd75845ca40f461e31350d86963dffec6cd6
---

diff --git a/manifest b/manifest
index 5751a22ada..f96cffda51 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Increase\sthe\snominal\srow\ssize\sfor\sIPK\sindex\slookups\sslightly,\sfor\sbetter\nbalance.
-D 2022-12-03T19:04:09.723
+C Use\sthe\ssmaller\sestimated\srow\ssize\sfor\ssearching\sIPK\stables,\sbut\suse\sthe\noriginal\slarger\srow\ssize\sestimate\sfor\sscanning,\ssince\sthe\sleaves\scan\shave\slarge\nrows.
+D 2022-12-05T02:42:30.931
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -732,7 +732,7 @@ F src/vxworks.h d2988f4e5a61a4dfe82c6524dd3d6e4f2ce3cdb9
 F src/wal.c b9df133a705093da8977da5eb202eaadb844839f1c7297c08d33471f5491843d
 F src/wal.h c3aa7825bfa2fe0d85bef2db94655f99870a285778baa36307c0a16da32b226a
 F src/walker.c f890a3298418d7cba3b69b8803594fdc484ea241206a8dfa99db6dd36f8cbb3b
-F src/where.c cf893bd9e48cc4f761beb490e2016cfec7791b0778808a84f2d3d6340085f0d5
+F src/where.c 20f4f51d2d5fb19b984e6ea381b26cf627cc93e64dd9b2ce6a94531aec2f5916
 F src/whereInt.h e25203e5bfee149f5f1225ae0166cfb4f1e65490c998a024249e98bb0647377c
 F src/wherecode.c ee52c2781c36004d23c85bf111063b78fc16e5e1b6a0d424326af8bf90babb0b
 F src/whereexpr.c 05295b44b54eea76d1ba766f0908928d0e20e990c249344c9521454d3d09c7ae
@@ -2065,8 +2065,8 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 9800586393c9d3b82459ef657620d245a7985ef5fa389b8a9ea633d6a29c7299
-R bdb8fcd5ad681651f9b1330561cafc6c
+P 1a61c500add4a2bfe80c0c691d559cfca166dc5f8262651a58da7ec16a51d430
+R 2840e735a826428dc7a6eae8bd9d8397
 U drh
-Z f5c8d079aea1d9c7b44238c2c41ad282
+Z f598756dbab89af8b8470b4640ebca93
 # Remove this line to create a well-formed Fossil manifest.
diff --git a/manifest.uuid b/manifest.uuid
index f3e63033d3..e4080b53cb 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-1a61c500add4a2bfe80c0c691d559cfca166dc5f8262651a58da7ec16a51d430
\ No newline at end of file
+df3818997b822743ac407dde45c5fd75845ca40f461e31350d86963dffec6cd6
\ No newline at end of file
diff --git a/src/where.c b/src/where.c
index 34a6f348d9..a133799472 100644
--- a/src/where.c
+++ b/src/where.c
@@ -3092,7 +3092,15 @@ static int whereLoopAddBtreeIndex(
     ** seek only. Then, if this is a non-covering index, add the cost of
     ** visiting the rows in the main table.  */
     assert( pSrc->pTab->szTabRow>0 );
-    rCostIdx = pNew->nOut + 1 + (15*pProbe->szIdxRow)/pSrc->pTab->szTabRow;
+    if( pProbe->idxType==SQLITE_IDXTYPE_IPK ){
+      /* The pProbe->szIdxRow is low for an IPK table since the interior
+      ** pages are small.  Thuse szIdxRow gives a good estimate of seek cost.
+      ** But the leaf pages are full-size, so pProbe->szIdxRow would badly
+      ** under-estimate the scanning cost. */
+      rCostIdx = pNew->nOut + 16;
+    }else{
+      rCostIdx = pNew->nOut + 1 + (15*pProbe->szIdxRow)/pSrc->pTab->szTabRow;
+    }
     pNew->rRun = sqlite3LogEstAdd(rLogSize, rCostIdx);
     if( (pNew->wsFlags & (WHERE_IDX_ONLY|WHERE_IPK|WHERE_EXPRIDX))==0 ){
       pNew->rRun = sqlite3LogEstAdd(pNew->rRun, pNew->nOut + 16);