If a table has one or more rows and it has a partial index has zero rows,

still make an entry in the sqlite_stat1 table for the partial index, so that
we know that "PRAGMA optimize" does not need to redo the whole table.

FossilOrigin-Name: e147b18991dd462fff367442acb0504fdf193a31843ed34ec8c1ced30747bf8a

4 files changed, 57 insertions, 46 deletions

diff --git a/src/analyze.c b/src/analyze.c
index 59e3d9837..e7c1068ae 100644
--- a/src/analyze.c
+++ b/src/analyze.c
@@ -872,7 +872,7 @@ static void statGet(
       if( iVal==2 && p->nRow*10 <= nDistinct*11 ) iVal = 1;
       sqlite3_str_appendf(&sStat, " %llu", iVal);
 #ifdef SQLITE_ENABLE_STAT4
-      assert( p->current.anEq[i] );
+      assert( p->current.anEq[i] || p->nRow==0 );
 #endif
     }
     sqlite3ResultStrAccum(context, &sStat);
@@ -1057,7 +1057,7 @@ static void analyzeOneTable(
 
   for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
     int nCol;                     /* Number of columns in pIdx. "N" */
-    int addrRewind;               /* Address of "OP_Rewind iIdxCur" */
+    int addrGotoEnd;               /* Address of "OP_Rewind iIdxCur" */
     int addrNextRow;              /* Address of "next_row:" */
     const char *zIdxName;         /* Name of the index */
     int nColTest;                 /* Number of columns to test for changes */
@@ -1081,9 +1081,14 @@ static void analyzeOneTable(
     /*
     ** Pseudo-code for loop that calls stat_push():
     **
-    **   Rewind csr
-    **   if eof(csr) goto end_of_scan;
     **   regChng = 0
+    **   Rewind csr
+    **   if eof(csr){
+    **      stat_init() with count = 0;
+    **      goto end_of_scan;
+    **   }
+    **   count()
+    **   stat_init()
     **   goto chng_addr_0;
     **
     **  next_row:
@@ -1122,41 +1127,36 @@ static void analyzeOneTable(
     sqlite3VdbeSetP4KeyInfo(pParse, pIdx);
     VdbeComment((v, "%s", pIdx->zName));
 
-    /* Invoke the stat_init() function. The arguments are:
-    ** 
+    /* Implementation of the following:
+    **
+    **   regChng = 0
+    **   Rewind csr
+    **   if eof(csr){
+    **      stat_init() with count = 0;
+    **      goto end_of_scan;
+    **   }
+    **   count()
+    **   stat_init()
+    **   goto chng_addr_0;
+    */
+    assert( regTemp2==regStat+4 );
+    sqlite3VdbeAddOp2(v, OP_Integer, db->nAnalysisLimit, regTemp2);
+
+    /* Arguments to stat_init(): 
     **    (1) the number of columns in the index including the rowid
     **        (or for a WITHOUT ROWID table, the number of PK columns),
     **    (2) the number of columns in the key without the rowid/pk
-    **    (3) estimated number of rows in the index,
-    */
+    **    (3) estimated number of rows in the index. */
     sqlite3VdbeAddOp2(v, OP_Integer, nCol, regStat+1);
     assert( regRowid==regStat+2 );
     sqlite3VdbeAddOp2(v, OP_Integer, pIdx->nKeyCol, regRowid);
-#ifdef SQLITE_ENABLE_STAT4
-    if( OptimizationEnabled(db, SQLITE_Stat4) ){
-      sqlite3VdbeAddOp2(v, OP_Count, iIdxCur, regTemp);
-      addrRewind = sqlite3VdbeAddOp1(v, OP_Rewind, iIdxCur);
-      VdbeCoverage(v);
-    }else
-#endif
-    {
-      addrRewind = sqlite3VdbeAddOp1(v, OP_Rewind, iIdxCur);
-      VdbeCoverage(v);
-      sqlite3VdbeAddOp3(v, OP_Count, iIdxCur, regTemp, 1);
-    }
-    assert( regTemp2==regStat+4 );
-    sqlite3VdbeAddOp2(v, OP_Integer, db->nAnalysisLimit, regTemp2);
+    sqlite3VdbeAddOp3(v, OP_Count, iIdxCur, regTemp,
+                      OptimizationDisabled(db, SQLITE_Stat4));
     sqlite3VdbeAddFunctionCall(pParse, 0, regStat+1, regStat, 4,
                                &statInitFuncdef, 0);
+    addrGotoEnd = sqlite3VdbeAddOp1(v, OP_Rewind, iIdxCur);
+    VdbeCoverage(v);
 
-    /* Implementation of the following:
-    **
-    **   Rewind csr
-    **   if eof(csr) goto end_of_scan;
-    **   regChng = 0
-    **   goto next_push_0;
-    **
-    */
     sqlite3VdbeAddOp2(v, OP_Integer, 0, regChng);
     addrNextRow = sqlite3VdbeCurrentAddr(v);
 
@@ -1263,6 +1263,12 @@ static void analyzeOneTable(
     }
 
     /* Add the entry to the stat1 table. */
+    if( pIdx->pPartIdxWhere ){
+      /* Partial indexes might get a zero-entry in sqlite_stat1.  But
+      ** an empty table is omitted from sqlite_stat1. */
+      sqlite3VdbeJumpHere(v, addrGotoEnd);
+      addrGotoEnd = 0;
+    }
     callStatGet(pParse, regStat, STAT_GET_STAT1, regStat1);
     assert( "BBB"[0]==SQLITE_AFF_TEXT );
     sqlite3VdbeAddOp4(v, OP_MakeRecord, regTabname, 3, regTemp, "BBB", 0);
@@ -1286,6 +1292,12 @@ static void analyzeOneTable(
       int addrIsNull;
       u8 seekOp = HasRowid(pTab) ? OP_NotExists : OP_NotFound;
 
+      /* No STAT4 data is generated if the number of rows is zero */
+      if( addrGotoEnd==0 ){
+        sqlite3VdbeAddOp2(v, OP_Cast, regStat1, SQLITE_AFF_INTEGER);
+        addrGotoEnd = sqlite3VdbeAddOp1(v, OP_IfNot, regStat1);
+      }
+
       if( doOnce ){
         int mxCol = nCol;
         Index *pX;
@@ -1338,7 +1350,7 @@ static void analyzeOneTable(
 #endif /* SQLITE_ENABLE_STAT4 */
 
     /* End of analysis */
-    sqlite3VdbeJumpHere(v, addrRewind);
+    if( addrGotoEnd ) sqlite3VdbeJumpHere(v, addrGotoEnd);
   }
 
 
diff --git a/src/btree.c b/src/btree.c
index 49c07c81a..16b683abe 100644
--- a/src/btree.c
+++ b/src/btree.c
@@ -6182,10 +6182,10 @@ i64 sqlite3BtreeRowCountEst(BtCursor *pCur){
   assert( cursorOwnsBtShared(pCur) );
   assert( sqlite3_mutex_held(pCur->pBtree->db->mutex) );
 
-  /* Currently this interface is only called by the OP_IfSmaller
-  ** opcode, and it that case the cursor will always be valid and
-  ** will always point to a leaf node. */
-  if( NEVER(pCur->eState!=CURSOR_VALID) ) return -1;
+  /* Currently this interface is only called by the OP_IfSizeBetween
+  ** opcode and the OP_Count opcode with P3=1.  In either case,
+  ** the cursor will always be valid unless the btree is empty. */
+  if( pCur->eState!=CURSOR_VALID ) return 0;
   if( NEVER(pCur->pPage->leaf==0) ) return -1;
 
   n = pCur->pPage->nCell;
diff --git a/src/pragma.c b/src/pragma.c
index 53dc9ced3..77ec9a57e 100644
--- a/src/pragma.c
+++ b/src/pragma.c
@@ -2427,9 +2427,8 @@ void sqlite3Pragma(
   **               database will usually be less than 100 milliseconds on
   **               a RaspberryPI-4 class machine.  On by default.
   **
-  **    0x00020    Run ANALYZE on any table that has a complete index
-  **               (an index without a WHERE clause) that lacks an entry
-  **               in the sqlite_stat1 table.  On by default.
+  **    0x00020    Run ANALYZE on any table that has a index that lacks an
+  **               entry in the sqlite_stat1 table.  On by default.
   **
   **    0x10000    Look at tables to see if they need to be reanalyzed
   **               due to growth or shrinkage even if they have not been
@@ -2454,14 +2453,14 @@ void sqlite3Pragma(
   **
   ** (4) One or more of the following is true:
   **      (4a) The 0x10000 MASK bit is set.
-  **      (4b) One or more complete indexes on the table lacks an entry
+  **      (4b) One or more indexes on the table lacks an entry
   **           in the sqlite_stat1 table.
   **      (4c) The query planner used sqlite_stat1-style statistics for one
   **           or more indexes of the tableat some point during the lifetime
   **           of the current connection.
   **
   ** (5) One or more of the following is true:
-  **      (5a) One or mroe complete indexes on the table lacks an entry
+  **      (5a) One or mroe indexes on the table lacks an entry
   **           in the sqlite_stat1 table.  (Same as 4a)
   **      (5b) The number of rows in the table has increased or decreased by
   **           10-fold.  In other words, the current size of the table is
@@ -2515,12 +2514,12 @@ void sqlite3Pragma(
         if( 0==sqlite3StrNICmp(pTab->zName, "sqlite_", 7) ) continue;
 
         /* Find the size of the table as last recorded in sqlite_stat1.
-        ** If any complete index (index without a WHERE clause) is unanalyzed,
-        ** then the threshold is -1 to indicate a new, unanalyzed index
+        ** If any index is unanalyzed, then the threshold is -1 to
+        ** indicate a new, unanalyzed index
         */
         szThreshold = pTab->nRowLogEst;
         for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
-          if( !pIdx->hasStat1 && pIdx->pPartIdxWhere==0 ){
+          if( !pIdx->hasStat1 ){
             szThreshold = -1; /* Always analyze if any index lacks statistics */
             break;
           }
@@ -2534,7 +2533,7 @@ void sqlite3Pragma(
         }else if( opMask & 0x10000 ){
           /* Check for size change if 0x10000 is set */
         }else if( pTab->pIndex!=0 && szThreshold<0 ){
-          /* Do analysis if unanalyzed complete indexes exists */
+          /* Do analysis if unanalyzed indexes exists */
         }else{
           /* Otherwise, we can skip this table */
           continue;
@@ -2549,7 +2548,7 @@ void sqlite3Pragma(
 
         /* Reanalyze if the table is 10 times larger or smaller than
         ** the last analysis.  Unconditional reanalysis if there are
-        ** unanalyzed complete indexes. */
+        ** unanalyzed indexes. */
         if( szThreshold>=0 ){
           LogEst iRange = 33;   /* 10x size change */
           sqlite3OpenTable(pParse, iTabCur, iDb, pTab, OP_OpenRead);
diff --git a/src/vdbe.c b/src/vdbe.c
index 3b52c13fa..48a029dbf 100644
--- a/src/vdbe.c
+++ b/src/vdbe.c
@@ -2086,7 +2086,7 @@ case OP_RealAffinity: {                  /* in1 */
 }
 #endif
 
-#ifndef SQLITE_OMIT_CAST
+#if !defined(SQLITE_OMIT_CAST) && !defined(SQLITE_OMIT_ANALYZE)
 /* Opcode: Cast P1 P2 * * *
 ** Synopsis: affinity(r[P1])
 **