Back out the "low-quality index" query planner hack of check-in

[bcac937526d9a6ef].  Subsequent query planner enhancements for dealing
with star-queries make that change unnecessary and the change was recently
found to cause a performance regression in an unrelated query.
Also fix a typo in a debugging message.

FossilOrigin-Name: e7dcf25efae364b7cdf9eb8265803c816c8b8557e4a7684da428badc6ffb3875

5 files changed, 12 insertions, 26 deletions

diff --git a/manifest b/manifest
index 5ad02672b..48c2ae526 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Fix\strunk\sfork.
-D 2025-05-13T19:06:11.380
+C Back\sout\sthe\s"low-quality\sindex"\squery\splanner\shack\sof\scheck-in\n[bcac937526d9a6ef].\s\sSubsequent\squery\splanner\senhancements\sfor\sdealing\nwith\sstar-queries\smake\sthat\schange\sunnecessary\sand\sthe\schange\swas\srecently\nfound\sto\scause\sa\sperformance\sregression\sin\san\sunrelated\squery.\nAlso\sfix\sa\stypo\sin\sa\sdebugging\smessage.
+D 2025-05-14T16:40:05.375
 F .fossil-settings/binary-glob 61195414528fb3ea9693577e1980230d78a1f8b0a54c78cf1b9b24d0a409ed6a x
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
@@ -720,7 +720,7 @@ F sqlite.pc.in 42b7bf0d02e08b9e77734a47798d1a55a9e0716b
 F sqlite3.1 acdff36db796e2d00225b911d3047d580cd136547298435426ce9d40347973cc
 F sqlite3.pc.in 0977c03a4da7c4204bd60e784a0efb8d51a190448aba78a4e973fe7192bdaf03
 F src/alter.c 6a21a487290ed0990a0fac9db6b0b09c63de4b1cdaa6ba3fa3872e6f26b87768
-F src/analyze.c 13895d4da6ac857d95d3291dc607d492eba3ea1cbc3bc04baaa0383fbc1bb3d4
+F src/analyze.c 03bcfc083fc0cccaa9ded93604e1d4244ea245c17285d463ef6a60425fcb247d
 F src/attach.c 9af61b63b10ee702b1594ecd24fb8cea0839cfdb6addee52fba26fa879f5db9d
 F src/auth.c 54ab9c6c5803b47c0d45b76ce27eff22a03b4b1f767c5945a3a4eb13aa4c78dc
 F src/backup.c 5c97e8023aab1ce14a42387eb3ae00ba5a0644569e3476f38661fa6f824c3523
@@ -790,7 +790,7 @@ F src/shell.c.in 2c904da4431fed365e7d5029b8cb2da46cb3e8cf8a09305d1478836a2301ea9
 F src/sqlite.h.in 22882ddd3a70751aa8864c81993ee4562ed54c2c508b6270f75e223ffee38e1b
 F src/sqlite3.rc 015537e6ac1eec6c7050e17b616c2ffe6f70fca241835a84a4f0d5937383c479
 F src/sqlite3ext.h 3f046c04ea3595d6bfda99b781926b17e672fd6d27da2ba6d8d8fc39981dcb54
-F src/sqliteInt.h 8b18ed676757ce49df633b603a465655aa105d9862821ffa9296afb189ba564f
+F src/sqliteInt.h ded2e1527c84603d9d91adccb63dda460d96a2e2f98111d0438a479aa0dbe4e3
 F src/sqliteLimit.h 6d817c28a8f19af95e6f4921933b7fbbca48a962bce0eb0ec81e8bb3ef38e68b
 F src/status.c 0e72e4f6be6ccfde2488eb63210297e75f569f3ce9920f6c3d77590ec6ce5ffd
 F src/table.c 0f141b58a16de7e2fbe81c308379e7279f4c6b50eb08efeec5892794a0ba30d1
@@ -869,7 +869,7 @@ F src/vxworks.h d2988f4e5a61a4dfe82c6524dd3d6e4f2ce3cdb9
 F src/wal.c bcf40795a09b699ad7e42624dd6282b13335164fbabcd5a98a717758cebef451
 F src/wal.h ba252daaa94f889f4b2c17c027e823d9be47ce39da1d3799886bbd51f0490452
 F src/walker.c d5006d6b005e4ea7302ad390957a8d41ed83faa177e412f89bc5600a7462a014
-F src/where.c 16aab5421a7119063fdb138dce6b53c57c50ad01b0b64992dacb14f946fe8d4a
+F src/where.c 1d06561f7310af61bef8a046fa95d463ad88f855be9036fec9091f984520afc5
 F src/whereInt.h ecdbfb5551cf394f04ec7f0bc7ad963146d80eee3071405ac29aa84950128b8e
 F src/wherecode.c d67fadf5430c2647773b5f702a47b82eb4af50a317f8978c0c82363cc1a5107f
 F src/whereexpr.c 2415c8eee5ff89a8b709d7d83d71c1ff986cd720d0520057e1d8a5371339012a
@@ -2207,8 +2207,8 @@ F tool/version-info.c 3b36468a90faf1bbd59c65fd0eb66522d9f941eedd364fabccd7227350
 F tool/warnings-clang.sh bbf6a1e685e534c92ec2bfba5b1745f34fb6f0bc2a362850723a9ee87c1b31a7
 F tool/warnings.sh 49a486c5069de041aedcbde4de178293e0463ae9918ecad7539eedf0ec77a139
 F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
-P fc254c1eb784c79a371bf961945a18a680982cdcd3fdcd7e6bb481712fe21cf8 c9e04dadfdf6c860631ce5603693add565ff2033aa25af5736302af7045fc91e
-R 2c951b894630034ec93ff56350c9beb9
+P 53644c42c5ee40e905a72bb014515e5e30265577d543eeca09139800822b5b42
+R 59151c194fe4122ae75c7906b9cce51d
 U drh
-Z 97e0cef690bfe86eb3019d1e3b04006a
+Z 6b734debe02b11e5124b69bb671a98d3
 # Remove this line to create a well-formed Fossil manifest.
diff --git a/manifest.uuid b/manifest.uuid
index 27abd2b13..eae3348ca 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-53644c42c5ee40e905a72bb014515e5e30265577d543eeca09139800822b5b42
+e7dcf25efae364b7cdf9eb8265803c816c8b8557e4a7684da428badc6ffb3875
diff --git a/src/analyze.c b/src/analyze.c
index 8ca0e3e74..2721f2523 100644
--- a/src/analyze.c
+++ b/src/analyze.c
@@ -1576,16 +1576,6 @@ static void decodeIntArray(
       while( z[0]!=0 && z[0]!=' ' ) z++;
       while( z[0]==' ' ) z++;
     }
-
-    /* Set the bLowQual flag if the peak number of rows obtained
-    ** from a full equality match is so large that a full table scan
-    ** seems likely to be faster than using the index.
-    */
-    if( aLog[0] > 66              /* Index has more than 100 rows */
-     && aLog[0] <= aLog[nOut-1]   /* And only a single value seen */
-    ){
-      pIndex->bLowQual = 1;
-    }
   }
 }
 
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index edf925964..af7ed4a4c 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -2789,7 +2789,6 @@ struct Index {
   unsigned isCovering:1;   /* True if this is a covering index */
   unsigned noSkipScan:1;   /* Do not try to use skip-scan if true */
   unsigned hasStat1:1;     /* aiRowLogEst values come from sqlite_stat1 */
-  unsigned bLowQual:1;     /* sqlite_stat1 says this is a low-quality index */
   unsigned bNoQuery:1;     /* Do not use this index to optimize queries */
   unsigned bAscKeyBug:1;   /* True if the bba7b69f9849b5bf bug applies */
   unsigned bIdxRowid:1;    /* One or more of the index keys is the ROWID */
diff --git a/src/where.c b/src/where.c
index c51d1ba81..0103db5e8 100644
--- a/src/where.c
+++ b/src/where.c
@@ -3159,11 +3159,8 @@ static int whereLoopAddBtreeIndex(
     assert( pNew->u.btree.nBtm==0 );
     opMask = WO_EQ|WO_IN|WO_GT|WO_GE|WO_LT|WO_LE|WO_ISNULL|WO_IS;
   }
-  if( pProbe->bUnordered || pProbe->bLowQual ){
-    if( pProbe->bUnordered ) opMask &= ~(WO_GT|WO_GE|WO_LT|WO_LE);
-    if( pProbe->bLowQual && pSrc->fg.isIndexedBy==0 ){ 
-      opMask &= ~(WO_EQ|WO_IN|WO_IS);
-    }
+  if( pProbe->bUnordered ){
+    opMask &= ~(WO_GT|WO_GE|WO_LT|WO_LE);
   }
 
   assert( pNew->u.btree.nEq<pProbe->nColumn );
@@ -4100,7 +4097,7 @@ static int whereLoopAddBtree(
            && (HasRowid(pTab) || pWInfo->pSelect!=0 || sqlite3FaultSim(700))
         ){
           WHERETRACE(0x200,
-             ("-> %s a covering index according to bitmasks\n",
+             ("-> %s is a covering index according to bitmasks\n",
              pProbe->zName, m==0 ? "is" : "is not"));
           pNew->wsFlags = WHERE_IDX_ONLY | WHERE_INDEXED;
         }