Increase the default SQLITE_MAX_SCHEMA_RETRY to 50. Make sure that macro

covers every case where a prepared statement might need to be reprepared due
to a schema change.  The sqlite3_exec() interface now uses 
sqlite3_prepare_v2().

FossilOrigin-Name: c1d7304c80c4a6244c8a9f6fad1eebd0f339c724

src/legacy.c

@@ -38,7 +38,6 @@ int sqlite3_exec(
   const char *zLeftover;      /* Tail of unprocessed SQL */
   sqlite3_stmt *pStmt = 0;    /* The current SQL statement */
   char **azCols = 0;          /* Names of result columns */
-  int nRetry = 0;             /* Number of retry attempts */
   int callbackIsInit;         /* True if callback data is initialized */
 
   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
@@ -46,12 +45,12 @@ int sqlite3_exec(
 
   sqlite3_mutex_enter(db->mutex);
   sqlite3Error(db, SQLITE_OK, 0);
-  while( (rc==SQLITE_OK || (rc==SQLITE_SCHEMA && (++nRetry)<2)) && zSql[0] ){
+  while( rc==SQLITE_OK && zSql[0] ){
     int nCol;
     char **azVals = 0;
 
     pStmt = 0;
-    rc = sqlite3_prepare(db, zSql, -1, &pStmt, &zLeftover);
+    rc = sqlite3_prepare_v2(db, zSql, -1, &pStmt, &zLeftover);
     assert( rc==SQLITE_OK || pStmt==0 );
     if( rc!=SQLITE_OK ){
       continue;
@@ -108,11 +107,8 @@ int sqlite3_exec(
       if( rc!=SQLITE_ROW ){
         rc = sqlite3VdbeFinalize((Vdbe *)pStmt);
         pStmt = 0;
-        if( rc!=SQLITE_SCHEMA ){
-          nRetry = 0;
-          zSql = zLeftover;
-          while( sqlite3Isspace(zSql[0]) ) zSql++;
-        }
+        zSql = zLeftover;
+        while( sqlite3Isspace(zSql[0]) ) zSql++;
         break;
       }
     }

src/prepare.c

@@ -654,7 +654,6 @@ static int sqlite3Prepare(
   }
 #endif
 
-  assert( db->init.busy==0 || saveSqlFlag==0 );
   if( db->init.busy==0 ){
     Vdbe *pVdbe = pParse->pVdbe;
     sqlite3VdbeSetSql(pVdbe, zSql, (int)(pParse->zTail-zSql), saveSqlFlag);

src/vdbeInt.h

@@ -18,6 +18,14 @@
 #ifndef _VDBEINT_H_
 #define _VDBEINT_H_
 
+/*
+** The maximum number of times that a statement will try to reparse
+** itself before giving up and returning SQLITE_SCHEMA.
+*/
+#ifndef SQLITE_MAX_SCHEMA_RETRY
+# define SQLITE_MAX_SCHEMA_RETRY 50
+#endif
+
 /*
 ** SQL is translated into a sequence of instructions to be
 ** executed by a virtual machine.  Each instruction is an instance

src/vdbeapi.c

@@ -453,14 +453,6 @@ end_of_step:
   return (rc&db->errMask);
 }
 
-/*
-** The maximum number of times that a statement will try to reparse
-** itself before giving up and returning SQLITE_SCHEMA.
-*/
-#ifndef SQLITE_MAX_SCHEMA_RETRY
-# define SQLITE_MAX_SCHEMA_RETRY 5
-#endif
-
 /*
 ** This is the top-level implementation of sqlite3_step().  Call
 ** sqlite3Step() to do most of the work.  If a schema error occurs,

src/vdbeblob.c

@@ -313,7 +313,7 @@ int sqlite3_blob_open(
     }
     sqlite3_bind_int64(pBlob->pStmt, 1, iRow);
     rc = blobSeekToRow(pBlob, iRow, &zErr);
-  } while( (++nAttempt)<5 && rc==SQLITE_SCHEMA );
+  } while( (++nAttempt)<SQLITE_MAX_SCHEMA_RETRY && rc==SQLITE_SCHEMA );
 
 blob_open_out:
   if( rc==SQLITE_OK && db->mallocFailed==0 ){