From: drh <>
Date: Sat, 3 Dec 2022 00:52:21 +0000 (+0000)
Subject: Tuning the query planner by adjusting the weights that predict the relative
X-Git-Tag: version-3.41.0~312^2~5
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=1edd0a089c81558d199d075ddcf5845703c62667;p=thirdparty%2Fsqlite.git

Tuning the query planner by adjusting the weights that predict the relative
performance of sorting and index lookup.

FossilOrigin-Name: 9f2806da4d88beceac2e81e05421f00481dd3dd100b096cd2ae6c828adb42ca7
---

diff --git a/manifest b/manifest
index 61b48477c1..a763dc6801 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Minor\sinternal\stweaks\sto\sthe\sOPFS\sVFS.\sResolve\sa\smissing\sresult\scode\swhich\slead\sto\sa\snull\sderef\sin\sxFileSize().
-D 2022-12-02T18:56:37.557
+C Tuning\sthe\squery\splanner\sby\sadjusting\sthe\sweights\sthat\spredict\sthe\srelative\nperformance\sof\ssorting\sand\sindex\slookup.
+D 2022-12-03T00:52:21.776
 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 bf470b5d1ba03af8d558a0c98cc1fa97b330e03a198a7af61895e5a2e8d93f20
+F src/where.c 5826b62ddcfc92979669cb5fb80f73d0df86bbfeefa1d757f5dc1f857cd628e7
 F src/whereInt.h e25203e5bfee149f5f1225ae0166cfb4f1e65490c998a024249e98bb0647377c
 F src/wherecode.c ee52c2781c36004d23c85bf111063b78fc16e5e1b6a0d424326af8bf90babb0b
 F src/whereexpr.c 05295b44b54eea76d1ba766f0908928d0e20e990c249344c9521454d3d09c7ae
@@ -1368,7 +1368,7 @@ F test/openv2.test 0d3040974bf402e19b7df4b783e447289d7ab394
 F test/optfuzz-db01.c 9f2fa80b8f84ebbf1f2e8b13421a4e0477fe300f6686fbd76cac1d2db66e0fdc
 F test/optfuzz-db01.txt 21f6bdeadc701cf11528276e2a55c70bfcb846ba42df327f979bd9e7b6ce7041
 F test/optfuzz.c 690430a0bf0ad047d5a168bf52b05b2ee97aedaad8c14337e9eb5050faa64994
-F test/orderby1.test a4bba04b9c60a21e53486fbc173a596b29641a3b3a57a0f26a1cbef1360358e9
+F test/orderby1.test 02cfd870127a7342170b829175c5c53e9e7405744451ac1aeb2f7e2b0c18ca76
 F test/orderby2.test bc11009f7cd99d96b1b11e57b199b00633eb5b04
 F test/orderby3.test 8619d06a3debdcd80a27c0fdea5c40b468854b99
 F test/orderby4.test 4d39bfbaaa3ae64d026ca2ff166353d2edca4ba4
@@ -1884,7 +1884,7 @@ F test/walthread.test 14b20fcfa6ae152f5d8e12f5dc8a8a724b7ef189f5d8ef1e2ceab79f2a
 F test/walvfs.test e1a6ad0f3c78e98b55c3d5f0889cf366cc0d0a1cb2bccb44ac9ec67384adc4a1
 F test/wapp.tcl b440cd8cf57953d3a49e7ee81e6a18f18efdaf113b69f7d8482b0710a64566ec
 F test/wapptest.tcl 1bea58a6a8e68a73f542ee4fca28b771b84ed803bd0c9e385087070b3d747b3c x
-F test/where.test d13cd7c24e80009d2b54e2f7a8893c457afa49c64f99359c9eb3fe668ba1d9d4
+F test/where.test 98208c95b574269980132c347b4bdb8992c6d5fc30c1954938593336d12e7447
 F test/where2.test 03c21a11e7b90e2845fc3c8b4002fc44cc2797fa74c86ee47d70bd7ea4f29ed6
 F test/where3.test 5b4ffc0ac2ea0fe92f02b1244b7531522fe4d7bccf6fa8741d54e82c10e67753
 F test/where4.test 4a371bfcc607f41d233701bdec33ac2972908ba8
@@ -2065,8 +2065,11 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 0d36021d107d3afca190ad61c3380536ad0cc2d493d345d48f9f9c1191741128
-R 6eba0a795b491027bc2604925d67afb7
-U stephan
-Z 379ecd060fe213536d8ac858396e84c5
+P 57dd593ef0efa17dfb3a9f4eac36d5b8b879e271de817d8cd94a8c8b56d31870
+R e47495a3cfe52da04033a615c7da71c2
+T *branch * qp-tuning
+T *sym-qp-tuning *
+T -sym-trunk *
+U drh
+Z bdcd0fcd9740989c0fc73b883156ab70
 # Remove this line to create a well-formed Fossil manifest.
diff --git a/manifest.uuid b/manifest.uuid
index 2c043a6432..d25f3c5d8c 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-57dd593ef0efa17dfb3a9f4eac36d5b8b879e271de817d8cd94a8c8b56d31870
\ No newline at end of file
+9f2806da4d88beceac2e81e05421f00481dd3dd100b096cd2ae6c828adb42ca7
\ No newline at end of file
diff --git a/src/where.c b/src/where.c
index c9eeabe8b6..f1d1df44c5 100644
--- a/src/where.c
+++ b/src/where.c
@@ -3472,7 +3472,7 @@ static int whereLoopAddBtree(
     sPk.aiRowLogEst = aiRowEstPk;
     sPk.onError = OE_Replace;
     sPk.pTable = pTab;
-    sPk.szIdxRow = pTab->szTabRow;
+    sPk.szIdxRow = 1;  /* Interior rows of IPK table are very small */
     sPk.idxType = SQLITE_IDXTYPE_IPK;
     aiRowEstPk[0] = pTab->nRowLogEst;
     aiRowEstPk[1] = 0;
@@ -4811,13 +4811,18 @@ static LogEst whereSortingCost(
   /* TUNING: Estimated cost of a full external sort, where N is 
   ** the number of rows to sort is:
   **
-  **   cost = (3.0 * N * log(N)).
+  **   cost = (K * N * log(N)).
   ** 
   ** Or, if the order-by clause has X terms but only the last Y 
   ** terms are out of order, then block-sorting will reduce the 
   ** sorting cost to:
   **
-  **   cost = (3.0 * N * log(N)) * (Y/X)
+  **   cost = (K * N * log(N)) * (Y/X)
+  **
+  ** The constant K is 2.0 for an external sort that is built around
+  ** the OP_SorterInsert, OP_SorterSort, and OP_SorterData opcodes.
+  ** For a sort built using OP_IdxInsert and OP_Sort (which is slower
+  ** by a constant factor), the constant K is 4.0.
   **
   ** The (Y/X) term is implemented using stack variable rScale
   ** below.
@@ -4825,7 +4830,8 @@ static LogEst whereSortingCost(
   LogEst rScale, rSortCost;
   assert( nOrderBy>0 && 66==sqlite3LogEst(100) );
   rScale = sqlite3LogEst((nOrderBy-nSorted)*100/nOrderBy) - 66;
-  rSortCost = nRow + rScale + 16;
+  rSortCost = nRow + rScale + 10;
+  if( pWInfo->wctrlFlags & WHERE_USE_LIMIT ) rSortCost += 10;
 
   /* Multiple by log(M) where M is the number of output rows.
   ** Use the LIMIT for M if it is smaller.  Or if this sort is for
@@ -4985,11 +4991,11 @@ static int wherePathSolver(WhereInfo *pWInfo, LogEst nRowEst){
                 pWInfo, nRowEst, nOrderBy, isOrdered
             );
           }
-          /* TUNING:  Add a small extra penalty (5) to sorting as an
+          /* TUNING:  Add a small extra penalty (3) to sorting as an
           ** extra encouragment to the query planner to select a plan
           ** where the rows emerge in the correct order without any sorting
           ** required. */
-          rCost = sqlite3LogEstAdd(rUnsorted, aSortCost[isOrdered]) + 5;
+          rCost = sqlite3LogEstAdd(rUnsorted, aSortCost[isOrdered]) + 3;
 
           WHERETRACE(0x002,
               ("---- sort cost=%-3d (%d/%d) increases cost %3d to %-3d\n",
diff --git a/test/orderby1.test b/test/orderby1.test
index 9b5df4c753..7432b5473d 100644
--- a/test/orderby1.test
+++ b/test/orderby1.test
@@ -43,6 +43,7 @@ do_test 1.0 {
         (NULL, 1, 3, 'one-c'),
         (NULL, 2, 1, 'two-a'),
         (NULL, 3, 1, 'three-a');
+    ANALYZE;
     COMMIT;
   }
 } {}
@@ -180,6 +181,7 @@ do_test 2.0 {
         (1,  3, 'one-c'),
         (20, 1, 'two-a'),
         (3,  1, 'three-a');
+    ANALYZE;
     COMMIT;
   }
 } {}
@@ -327,6 +329,7 @@ do_test 3.0 {
         (NULL, 1, 3, 'one-c'),
         (NULL, 2, 1, 'two-a'),
         (NULL, 3, 1, 'three-a');
+    ANALYZE;
     COMMIT;
   }
 } {}
diff --git a/test/where.test b/test/where.test
index e28861bc10..3f4aa8e1be 100644
--- a/test/where.test
+++ b/test/where.test
@@ -545,6 +545,7 @@ do_test where-6.1 {
     CREATE INDEX t3acb ON t3(a,c,b);
     INSERT INTO t3 SELECT w, 101-w, y FROM t1;
     SELECT count(*), sum(a), sum(b), sum(c) FROM t3;
+    ANALYZE;
   }
 } {100 5050 5050 348550}
 do_test where-6.2 {