Add an sqlite3_db_config() option - SQLITE_DBCONFIG_STMT_SCANSTATS - for enabling and disabling the collection of sqlite3_stmt_scanstats() statistics in SQLITE_ENABLE_STMT_SCANSTATUS builds. Collection of statistics is disabled by default.

FossilOrigin-Name: 0f5579bef27b84ee855065cfe87703c51e1f9773906a9e0d4e4dafc90bd0e553

10 files changed, 119 insertions, 77 deletions

diff --git a/src/global.c b/src/global.c
index 799b1e47c..b018c5002 100644
--- a/src/global.c
+++ b/src/global.c
@@ -291,7 +291,7 @@ SQLITE_WSD struct Sqlite3Config sqlite3Config = {
    SQLITE_DEFAULT_SORTERREF_SIZE,   /* szSorterRef */
    0,                         /* iPrngSeed */
 #ifdef SQLITE_DEBUG
-   {0,0,0,0,0,0}              /* aTune */
+   {0,0,0,0,0,0},             /* aTune */
 #endif
 };
 
diff --git a/src/main.c b/src/main.c
index 9ec313e6f..a0e5e6585 100644
--- a/src/main.c
+++ b/src/main.c
@@ -970,6 +970,7 @@ int sqlite3_db_config(sqlite3 *db, int op, ...){
         { SQLITE_DBCONFIG_DQS_DML,               SQLITE_DqsDML         },
         { SQLITE_DBCONFIG_LEGACY_FILE_FORMAT,    SQLITE_LegacyFileFmt  },
         { SQLITE_DBCONFIG_TRUSTED_SCHEMA,        SQLITE_TrustedSchema  },
+        { SQLITE_DBCONFIG_STMT_SCANSTATS,        SQLITE_StmtScanStats  },
       };
       unsigned int i;
       rc = SQLITE_ERROR; /* IMP: R-42790-23372 */
diff --git a/src/shell.c.in b/src/shell.c.in
index 5c8d47e9a..a983ec0c0 100644
--- a/src/shell.c.in
+++ b/src/shell.c.in
@@ -5416,8 +5416,13 @@ static void open_db(ShellState *p, int openFlags){
     }
 #endif
   }
-  if( p->bSafeModePersist && p->db!=0 ){
-    sqlite3_set_authorizer(p->db, safeModeAuth, p);
+  if( p->db!=0 ){
+    if( p->bSafeModePersist ){
+      sqlite3_set_authorizer(p->db, safeModeAuth, p);
+    }
+    sqlite3_db_config(
+        p->db, SQLITE_DBCONFIG_STMT_SCANSTATS, p->scanstatsOn, (int*)0
+    );
   }
 }
 
@@ -9769,6 +9774,9 @@ static int do_meta_command(char *zLine, ShellState *p){
       }else{
         p->scanstatsOn = (u8)booleanValue(azArg[1]);
       }
+      sqlite3_db_config(
+          p->db, SQLITE_DBCONFIG_STMT_SCANSTATS, p->scanstatsOn, (int*)0
+      );
 #ifndef SQLITE_ENABLE_STMT_SCANSTATUS
       raw_printf(stderr, "Warning: .scanstats not available in this build.\n");
 #endif
diff --git a/src/sqlite.h.in b/src/sqlite.h.in
index 06737e1c9..0a31ba033 100644
--- a/src/sqlite.h.in
+++ b/src/sqlite.h.in
@@ -2456,6 +2456,16 @@ struct sqlite3_mem_methods {
 ** not considered a bug since SQLite versions 3.3.0 and earlier do not support
 ** either generated columns or decending indexes.
 ** </dd>
+
+** [[SQLITE_DBCONFIG_STMT_SCANSTATS]]
+** <dt>SQLITE_DBCONFIG_STMT_SCANSTATS</td>
+** <dd>The SQLITE_DBCONFIG_STMT_SCANSTATS option is only useful in
+** SQLITE_ENABLE_STMT_SCANSTATS builds. In this case, it sets or clears
+** a flag that enables collection of the sqlite3_stmt_scanstatus_v2()
+** statistics. For statistics to be collected, the flag must be set on
+** the database handle both when the SQL statement is prepared and when it 
+** is stepped. The flag is clear (collection of statistics is disabled)
+** by default.
 ** </dl>
 */
 #define SQLITE_DBCONFIG_MAINDBNAME            1000 /* const char* */
@@ -2476,7 +2486,8 @@ struct sqlite3_mem_methods {
 #define SQLITE_DBCONFIG_ENABLE_VIEW           1015 /* int int* */
 #define SQLITE_DBCONFIG_LEGACY_FILE_FORMAT    1016 /* int int* */
 #define SQLITE_DBCONFIG_TRUSTED_SCHEMA        1017 /* int int* */
-#define SQLITE_DBCONFIG_MAX                   1017 /* Largest DBCONFIG */
+#define SQLITE_DBCONFIG_STMT_SCANSTATS        1018 /* int int* */
+#define SQLITE_DBCONFIG_MAX                   1018 /* Largest DBCONFIG */
 
 /*
 ** CAPI3REF: Enable Or Disable Extended Result Codes
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index 40afc08db..21ad2fa7e 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -1757,7 +1757,7 @@ struct sqlite3 {
 #define SQLITE_NullCallback   0x00000100  /* Invoke the callback once if the */
                                           /*   result set is empty */
 #define SQLITE_IgnoreChecks   0x00000200  /* Do not enforce check constraints */
-#define SQLITE_ReadUncommit   0x00000400  /* READ UNCOMMITTED in shared-cache */
+#define SQLITE_StmtScanStats  0x00000400  /* Enable stmt_scanstats() counters */
 #define SQLITE_NoCkptOnClose  0x00000800  /* No checkpoint on close()/DETACH */
 #define SQLITE_ReverseOrder   0x00001000  /* Reverse unordered SELECTs */
 #define SQLITE_RecTriggers    0x00002000  /* Enable recursive triggers */
@@ -1783,6 +1783,7 @@ struct sqlite3 {
                                           /*   DELETE, or UPDATE and return */
                                           /*   the count using a callback. */
 #define SQLITE_CorruptRdOnly  HI(0x00002) /* Prohibit writes due to error */
+#define SQLITE_ReadUncommit   HI(0x00004) /* READ UNCOMMITTED in shared-cache */
 
 /* Flags used only if debugging */
 #ifdef SQLITE_DEBUG
@@ -5581,4 +5582,10 @@ int sqlite3KvvfsInit(void);
 sqlite3_uint64 sqlite3Hwtime(void);
 #endif
 
+#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
+# define IS_STMT_SCANSTATUS(db) (db->flags & SQLITE_StmtScanStats)
+#else
+# define IS_STMT_SCANSTATUS(db) 0
+#endif
+
 #endif /* SQLITEINT_H */
diff --git a/src/test1.c b/src/test1.c
index 421fad540..a765a66fa 100644
--- a/src/test1.c
+++ b/src/test1.c
@@ -2400,7 +2400,6 @@ static int SQLITE_TCLAPI test_create_null_module(
   int objc,
   Tcl_Obj *CONST objv[]
 ){
-  int rc;
   sqlite3 *db;
   char *zName;
 
@@ -8314,6 +8313,7 @@ static int SQLITE_TCLAPI test_sqlite3_db_config(
     { "DQS_DML",            SQLITE_DBCONFIG_DQS_DML },
     { "DQS_DDL",            SQLITE_DBCONFIG_DQS_DDL },
     { "LEGACY_FILE_FORMAT", SQLITE_DBCONFIG_LEGACY_FILE_FORMAT },
+    { "STMT_SCANSTATS",     SQLITE_DBCONFIG_STMT_SCANSTATS },
   };
   int i;
   int v = 0;
diff --git a/src/vdbe.c b/src/vdbe.c
index 61ff0b3cc..2bb4964c3 100644
--- a/src/vdbe.c
+++ b/src/vdbe.c
@@ -736,6 +736,7 @@ int sqlite3VdbeExec(
   Mem *pOut = 0;             /* Output operand */
 #if defined(SQLITE_ENABLE_STMT_SCANSTATUS) || defined(VDBE_PROFILE)
   u64 *pnCycle = 0;
+  int bStmtScanStatus = IS_STMT_SCANSTATUS(db)!=0;
 #endif
   /*** INSERT STACK UNION HERE ***/
 
@@ -800,13 +801,17 @@ int sqlite3VdbeExec(
 
     assert( pOp>=aOp && pOp<&aOp[p->nOp]);
     nVmStep++;
-#if defined(SQLITE_ENABLE_STMT_SCANSTATUS) || defined(VDBE_PROFILE)
+
+#if defined(VDBE_PROFILE)
     pOp->nExec++;
     pnCycle = &pOp->nCycle;
-# ifdef VDBE_PROFILE
-    if( sqlite3NProfileCnt==0 )
-# endif
+    if( sqlite3NProfileCnt==0 ) *pnCycle -= sqlite3Hwtime();
+#elif defined(SQLITE_ENABLE_STMT_SCANSTATUS)
+    if( bStmtScanStatus ){
+      pOp->nExec++;
+      pnCycle = &pOp->nCycle;
       *pnCycle -= sqlite3Hwtime();
+    }
 #endif
 
     /* Only allow tracing if SQLITE_DEBUG is defined.
@@ -8758,8 +8763,10 @@ default: {          /* This is really OP_Noop, OP_Explain */
     *pnCycle += sqlite3NProfileCnt ? sqlite3NProfileCnt : sqlite3Hwtime();
     pnCycle = 0;
 #elif defined(SQLITE_ENABLE_STMT_SCANSTATUS)
-    *pnCycle += sqlite3Hwtime();
-    pnCycle = 0;
+    if( pnCycle ){
+      *pnCycle += sqlite3Hwtime();
+      pnCycle = 0;
+    }
 #endif
 
     /* The following code adds nothing to the actual functionality
diff --git a/src/vdbeaux.c b/src/vdbeaux.c
index d04d8f1e1..87fd06732 100644
--- a/src/vdbeaux.c
+++ b/src/vdbeaux.c
@@ -443,10 +443,10 @@ void sqlite3ExplainBreakpoint(const char *z1, const char *z2){
 */
 int sqlite3VdbeExplain(Parse *pParse, u8 bPush, const char *zFmt, ...){
   int addr = 0;
-#if !defined(SQLITE_DEBUG) && !defined(SQLITE_ENABLE_STMT_SCANSTATUS)
+#if !defined(SQLITE_DEBUG)
   /* Always include the OP_Explain opcodes if SQLITE_DEBUG is defined.
   ** But omit them (for performance) during production builds */
-  if( pParse->explain==2 )
+  if( pParse->explain==2 || IS_STMT_SCANSTATUS(pParse->db) )
 #endif
   {
     char *zMsg;
@@ -1122,18 +1122,20 @@ void sqlite3VdbeScanStatus(
   LogEst nEst,                    /* Estimated number of output rows */
   const char *zName               /* Name of table or index being scanned */
 ){
-  sqlite3_int64 nByte = (p->nScan+1) * sizeof(ScanStatus);
-  ScanStatus *aNew;
-  aNew = (ScanStatus*)sqlite3DbRealloc(p->db, p->aScan, nByte);
-  if( aNew ){
-    ScanStatus *pNew = &aNew[p->nScan++];
-    memset(pNew, 0, sizeof(ScanStatus));
-    pNew->addrExplain = addrExplain;
-    pNew->addrLoop = addrLoop;
-    pNew->addrVisit = addrVisit;
-    pNew->nEst = nEst;
-    pNew->zName = sqlite3DbStrDup(p->db, zName);
-    p->aScan = aNew;
+  if( IS_STMT_SCANSTATUS(p->db) ){
+    sqlite3_int64 nByte = (p->nScan+1) * sizeof(ScanStatus);
+    ScanStatus *aNew;
+    aNew = (ScanStatus*)sqlite3DbRealloc(p->db, p->aScan, nByte);
+    if( aNew ){
+      ScanStatus *pNew = &aNew[p->nScan++];
+      memset(pNew, 0, sizeof(ScanStatus));
+      pNew->addrExplain = addrExplain;
+      pNew->addrLoop = addrLoop;
+      pNew->addrVisit = addrVisit;
+      pNew->nEst = nEst;
+      pNew->zName = sqlite3DbStrDup(p->db, zName);
+      p->aScan = aNew;
+    }
   }
 }
 
@@ -1150,20 +1152,22 @@ void sqlite3VdbeScanStatusRange(
   int addrStart, 
   int addrEnd
 ){
-  ScanStatus *pScan = 0;
-  int ii;
-  for(ii=p->nScan-1; ii>=0; ii--){
-    pScan = &p->aScan[ii];
-    if( pScan->addrExplain==addrExplain ) break;
-    pScan = 0;
-  }
-  if( pScan ){
-    if( addrEnd<0 ) addrEnd = sqlite3VdbeCurrentAddr(p)-1;
-    for(ii=0; ii<ArraySize(pScan->aAddrRange); ii+=2){
-      if( pScan->aAddrRange[ii]==0 ){
-        pScan->aAddrRange[ii] = addrStart;
-        pScan->aAddrRange[ii+1] = addrEnd;
-        break;
+  if( IS_STMT_SCANSTATUS(p->db) ){
+    ScanStatus *pScan = 0;
+    int ii;
+    for(ii=p->nScan-1; ii>=0; ii--){
+      pScan = &p->aScan[ii];
+      if( pScan->addrExplain==addrExplain ) break;
+      pScan = 0;
+    }
+    if( pScan ){
+      if( addrEnd<0 ) addrEnd = sqlite3VdbeCurrentAddr(p)-1;
+      for(ii=0; ii<ArraySize(pScan->aAddrRange); ii+=2){
+        if( pScan->aAddrRange[ii]==0 ){
+          pScan->aAddrRange[ii] = addrStart;
+          pScan->aAddrRange[ii+1] = addrEnd;
+          break;
+        }
       }
     }
   }
@@ -1180,19 +1184,21 @@ void sqlite3VdbeScanStatusCounters(
   int addrLoop, 
   int addrVisit
 ){
-  ScanStatus *pScan = 0;
-  int ii;
-  for(ii=p->nScan-1; ii>=0; ii--){
-    pScan = &p->aScan[ii];
-    if( pScan->addrExplain==addrExplain ) break;
-    pScan = 0;
-  }
-  if( pScan ){
-    pScan->addrLoop = addrLoop;
-    pScan->addrVisit = addrVisit;
+  if( IS_STMT_SCANSTATUS(p->db) ){
+    ScanStatus *pScan = 0;
+    int ii;
+    for(ii=p->nScan-1; ii>=0; ii--){
+      pScan = &p->aScan[ii];
+      if( pScan->addrExplain==addrExplain ) break;
+      pScan = 0;
+    }
+    if( pScan ){
+      pScan->addrLoop = addrLoop;
+      pScan->addrVisit = addrVisit;
+    }
   }
 }
-#endif
+#endif /* defined(SQLITE_ENABLE_STMT_SCANSTATUS) */
 
 
 /*
diff --git a/src/where.c b/src/where.c
index f71380592..8f6bc24be 100644
--- a/src/where.c
+++ b/src/where.c
@@ -831,7 +831,7 @@ static void explainAutomaticIndex(
   int bPartial,                   /* True if pIdx is a partial index */
   int *pAddrExplain               /* OUT: Address of OP_Explain */
 ){
-  if( pParse->explain!=2 ){
+  if( IS_STMT_SCANSTATUS(pParse->db) && pParse->explain!=2 ){
     Table *pTab = pIdx->pTable;
     const char *zSep = "";
     char *zText = 0;
diff --git a/src/wherecode.c b/src/wherecode.c
index 860acb44c..f74273cf1 100644
--- a/src/wherecode.c
+++ b/src/wherecode.c
@@ -111,9 +111,9 @@ static void explainIndexRange(StrAccum *pStr, WhereLoop *pLoop){
 
 /*
 ** This function is a no-op unless currently processing an EXPLAIN QUERY PLAN
-** command, or if either SQLITE_DEBUG or SQLITE_ENABLE_STMT_SCANSTATUS was
-** defined at compile-time. If it is not a no-op, a single OP_Explain opcode 
-** is added to the output to describe the table scan strategy in pLevel.
+** command, or if stmt_scanstatus_v2() stats are enabled, or if SQLITE_DEBUG 
+** was defined at compile-time. If it is not a no-op, a single OP_Explain
+** opcode is added to the output to describe the table scan strategy in pLevel.
 **
 ** If an OP_Explain opcode is added to the VM, its address is returned.
 ** Otherwise, if no OP_Explain is coded, zero is returned.
@@ -125,8 +125,8 @@ int sqlite3WhereExplainOneScan(
   u16 wctrlFlags                  /* Flags passed to sqlite3WhereBegin() */
 ){
   int ret = 0;
-#if !defined(SQLITE_DEBUG) && !defined(SQLITE_ENABLE_STMT_SCANSTATUS)
-  if( sqlite3ParseToplevel(pParse)->explain==2 )
+#if !defined(SQLITE_DEBUG)
+  if( sqlite3ParseToplevel(pParse)->explain==2 || IS_STMT_SCANSTATUS(pParse->db) )
 #endif
   {
     SrcItem *pItem = &pTabList->a[pLevel->iFrom];
@@ -292,27 +292,29 @@ void sqlite3WhereAddScanStatus(
   WhereLevel *pLvl,               /* Level to add scanstatus() entry for */
   int addrExplain                 /* Address of OP_Explain (or 0) */
 ){
-  const char *zObj = 0;
-  WhereLoop *pLoop = pLvl->pWLoop;
-  int wsFlags = pLoop->wsFlags;
-  int viaCoroutine = 0;
-
-  if( (wsFlags & WHERE_VIRTUALTABLE)==0  &&  pLoop->u.btree.pIndex!=0 ){
-    zObj = pLoop->u.btree.pIndex->zName;
-  }else{
-    zObj = pSrclist->a[pLvl->iFrom].zName;
-    viaCoroutine = pSrclist->a[pLvl->iFrom].fg.viaCoroutine;
-  }
-  sqlite3VdbeScanStatus(
-      v, addrExplain, pLvl->addrBody, pLvl->addrVisit, pLoop->nOut, zObj
-  );
-
-  if( viaCoroutine==0 ){
-    if( (wsFlags & (WHERE_MULTI_OR|WHERE_AUTO_INDEX))==0 ){
-      sqlite3VdbeScanStatusRange(v, addrExplain, -1, pLvl->iTabCur);
+  if( IS_STMT_SCANSTATUS( sqlite3VdbeDb(v) ) ){
+    const char *zObj = 0;
+    WhereLoop *pLoop = pLvl->pWLoop;
+    int wsFlags = pLoop->wsFlags;
+    int viaCoroutine = 0;
+
+    if( (wsFlags & WHERE_VIRTUALTABLE)==0  &&  pLoop->u.btree.pIndex!=0 ){
+      zObj = pLoop->u.btree.pIndex->zName;
+    }else{
+      zObj = pSrclist->a[pLvl->iFrom].zName;
+      viaCoroutine = pSrclist->a[pLvl->iFrom].fg.viaCoroutine;
     }
-    if( wsFlags & WHERE_INDEXED ){
-      sqlite3VdbeScanStatusRange(v, addrExplain, -1, pLvl->iIdxCur);
+    sqlite3VdbeScanStatus(
+        v, addrExplain, pLvl->addrBody, pLvl->addrVisit, pLoop->nOut, zObj
+    );
+
+    if( viaCoroutine==0 ){
+      if( (wsFlags & (WHERE_MULTI_OR|WHERE_AUTO_INDEX))==0 ){
+        sqlite3VdbeScanStatusRange(v, addrExplain, -1, pLvl->iTabCur);
+      }
+      if( wsFlags & WHERE_INDEXED ){
+        sqlite3VdbeScanStatusRange(v, addrExplain, -1, pLvl->iIdxCur);
+      }
     }
   }
 }