1 files changed, 43 insertions, 31 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);
   }