The query planner tries to avoids using indexes that use unknown collating

functions.

FossilOrigin-Name: 02013fc120bf71a8be3550c696a588af8c92f2209f8e5db530624878ddc8aa7e

6 files changed, 28 insertions, 18 deletions

diff --git a/src/build.c b/src/build.c
index fc4dbcdba..9582f136c 100644
--- a/src/build.c
+++ b/src/build.c
@@ -4364,6 +4364,18 @@ KeyInfo *sqlite3KeyInfoOfIndex(Parse *pParse, Index *pIdx){
       pKey->aSortOrder[i] = pIdx->aSortOrder[i];
     }
     if( pParse->nErr ){
+      assert( pParse->rc==SQLITE_ERROR_MISSING_COLLSEQ );
+      if( pIdx->bNoQuery==0 ){
+        /* Deactivate the index because it contains an unknown collating
+        ** sequence.  The only way to reactive the index is to reload the
+        ** schema.  Adding the missing collating sequence later does not
+        ** reactive the index.  The application had the chance to register
+        ** the missing index using the collation-needed callback.  For
+        ** simplicity, SQLite will not give the application a second chance.
+        */
+        pIdx->bNoQuery = 1;
+        pParse->rc = SQLITE_ERROR_RETRY;
+      }
       sqlite3KeyInfoUnref(pKey);
       pKey = 0;
     }
diff --git a/src/callback.c b/src/callback.c
index e08924b2c..0396df7a0 100644
--- a/src/callback.c
+++ b/src/callback.c
@@ -105,6 +105,7 @@ CollSeq *sqlite3GetCollSeq(
   assert( !p || p->xCmp );
   if( p==0 ){
     sqlite3ErrorMsg(pParse, "no such collation sequence: %s", zName);
+    pParse->rc = SQLITE_ERROR_MISSING_COLLSEQ;
   }
   return p;
 }
diff --git a/src/prepare.c b/src/prepare.c
index 9141cb8a7..65a4afcbb 100644
--- a/src/prepare.c
+++ b/src/prepare.c
@@ -655,8 +655,6 @@ static int sqlite3Prepare(
 end_prepare:
 
   sqlite3ParserReset(&sParse);
-  rc = sqlite3ApiExit(db, rc);
-  assert( (rc&db->errMask)==rc );
   return rc;
 }
 static int sqlite3LockAndPrepare(
@@ -669,6 +667,7 @@ static int sqlite3LockAndPrepare(
   const char **pzTail       /* OUT: End of parsed string */
 ){
   int rc;
+  int cnt = 0;
 
 #ifdef SQLITE_ENABLE_API_ARMOR
   if( ppStmt==0 ) return SQLITE_MISUSE_BKPT;
@@ -679,15 +678,18 @@ static int sqlite3LockAndPrepare(
   }
   sqlite3_mutex_enter(db->mutex);
   sqlite3BtreeEnterAll(db);
-  rc = sqlite3Prepare(db, zSql, nBytes, prepFlags, pOld, ppStmt, pzTail);
-  if( rc==SQLITE_SCHEMA ){
-    sqlite3ResetOneSchema(db, -1);
-    sqlite3_finalize(*ppStmt);
+  do{
+    /* Make multiple attempts to compile the SQL, until it either succeeds
+    ** or encounters a permanent error.  A schema problem after one schema
+    ** reset is considered a permanent error. */
     rc = sqlite3Prepare(db, zSql, nBytes, prepFlags, pOld, ppStmt, pzTail);
-  }
+    assert( rc==SQLITE_OK || *ppStmt==0 );
+  }while( rc==SQLITE_ERROR_RETRY
+       || (rc==SQLITE_SCHEMA && (sqlite3ResetOneSchema(db,-1), cnt++)==0) );
   sqlite3BtreeLeaveAll(db);
+  rc = sqlite3ApiExit(db, rc);
+  assert( (rc&db->errMask)==rc );
   sqlite3_mutex_leave(db->mutex);
-  assert( rc==SQLITE_OK || *ppStmt==0 );
   return rc;
 }
 
diff --git a/src/sqlite.h.in b/src/sqlite.h.in
index 443406442..29b0458d7 100644
--- a/src/sqlite.h.in
+++ b/src/sqlite.h.in
@@ -470,6 +470,8 @@ int sqlite3_exec(
 ** the most recent error can be obtained using
 ** [sqlite3_extended_errcode()].
 */
+#define SQLITE_ERROR_MISSING_COLLSEQ   (SQLITE_ERROR | (1<<8))
+#define SQLITE_ERROR_RETRY             (SQLITE_ERROR | (2<<8))
 #define SQLITE_IOERR_READ              (SQLITE_IOERR | (1<<8))
 #define SQLITE_IOERR_SHORT_READ        (SQLITE_IOERR | (2<<8))
 #define SQLITE_IOERR_WRITE             (SQLITE_IOERR | (3<<8))
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index 27b896d67..47d9fc695 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -2172,6 +2172,7 @@ 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 bNoQuery:1;     /* Do not use this index to optimize queries */
 #ifdef SQLITE_ENABLE_STAT3_OR_STAT4
   int nSample;             /* Number of elements in aSample[] */
   int nSampleCol;          /* Size of IndexSample.anEq[] and so on */
@@ -2984,7 +2985,7 @@ struct Parse {
   int nMem;            /* Number of memory cells used so far */
   int nOpAlloc;        /* Number of slots allocated for Vdbe.aOp[] */
   int szOpAlloc;       /* Bytes of memory space allocated for Vdbe.aOp[] */
-  int iSelfTab;        /* Table for associated with an index on expr, or negative
+  int iSelfTab;        /* Table associated with an index on expr, or negative
                        ** of the base register during check-constraint eval */
   int iCacheLevel;     /* ColCache valid when aColCache[].iLevel<=iCacheLevel */
   int iCacheCnt;       /* Counter used to generate aColCache[].lru values */
diff --git a/src/where.c b/src/where.c
index e11194bdd..5b77b7662 100644
--- a/src/where.c
+++ b/src/where.c
@@ -2879,6 +2879,7 @@ static int whereLoopAddBtree(
       testcase( pNew->iTab!=pSrc->iCursor );  /* See ticket [98d973b8f5] */
       continue;  /* Partial index inappropriate for this query */
     }
+    if( pProbe->bNoQuery ) continue;
     rSize = pProbe->aiRowLogEst[0];
     pNew->u.btree.nEq = 0;
     pNew->u.btree.nBtm = 0;
@@ -4870,16 +4871,7 @@ WhereInfo *sqlite3WhereBegin(
       assert( iIndexCur>=0 );
       if( op ){
         sqlite3VdbeAddOp3(v, op, iIndexCur, pIx->tnum, iDb);
-
-        /* If the index is only being scanned - if there is no searching -
-        ** then no collating functions are required.  Set db->init.busy in that
-        ** case, to prevent sqlite3VdbeSetP4KeyInfo() from raising needless
-        ** errors about the missing collating functions. */
-        assert( db->init.busy==0 );
-        db->init.busy = (pLoop->wsFlags & ~(WHERE_IDX_ONLY|WHERE_INDEXED))==0;
         sqlite3VdbeSetP4KeyInfo(pParse, pIx);
-        db->init.busy = 0;  /* Restore db->init.busy */
-
         if( (pLoop->wsFlags & WHERE_CONSTRAINT)!=0
          && (pLoop->wsFlags & (WHERE_COLUMN_RANGE|WHERE_SKIPSCAN))==0
          && (pWInfo->wctrlFlags&WHERE_ORDERBY_MIN)==0