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SQLite training in Houston TX on 2019-11-05 (details)
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Overview
Comment:Add new sqlite3_prepare_v3() flag SQLITE_PREPARE_NO_VTAB, for preparing statements that are not allowed to use any virtual tables. Use this to prevent circular references in triggers on virtual table shadow tables from causing resource leaks.
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Timelines: family | ancestors | descendants | both | prepare-no-vtab
Files: files | file ages | folders
SHA3-256: 25666e3d03950caf753295cdb55df162e07dbcf6840b05875c6e0b127c469ecb
User & Date: dan 2018-12-21 19:29:11
Context
2018-12-21
19:30
Add tests for the use of SQLITE_PREPARE_NO_VTAB in fts5. check-in: 19996120 user: dan tags: prepare-no-vtab
19:29
Add new sqlite3_prepare_v3() flag SQLITE_PREPARE_NO_VTAB, for preparing statements that are not allowed to use any virtual tables. Use this to prevent circular references in triggers on virtual table shadow tables from causing resource leaks. check-in: 25666e3d user: dan tags: prepare-no-vtab
18:51
In FTS3, avoid calling memcpy() with a NULL source pointer, even if the transfer amount is zero bytes. check-in: 1abb83d2 user: drh tags: trunk
Changes
Hide Diffs Unified Diffs Ignore Whitespace Patch

Changes to ext/fts3/fts3_write.c.

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  sqlite3_stmt *pStmt;

  assert( SizeofArray(azSql)==SizeofArray(p->aStmt) );
  assert( eStmt<SizeofArray(azSql) && eStmt>=0 );
  
  pStmt = p->aStmt[eStmt];
  if( !pStmt ){

    char *zSql;
    if( eStmt==SQL_CONTENT_INSERT ){
      zSql = sqlite3_mprintf(azSql[eStmt], p->zDb, p->zName, p->zWriteExprlist);
    }else if( eStmt==SQL_SELECT_CONTENT_BY_ROWID ){

      zSql = sqlite3_mprintf(azSql[eStmt], p->zReadExprlist);
    }else{
      zSql = sqlite3_mprintf(azSql[eStmt], p->zDb, p->zName);
    }
    if( !zSql ){
      rc = SQLITE_NOMEM;
    }else{
      rc = sqlite3_prepare_v3(p->db, zSql, -1, SQLITE_PREPARE_PERSISTENT,
                              &pStmt, NULL);
      sqlite3_free(zSql);
      assert( rc==SQLITE_OK || pStmt==0 );
      p->aStmt[eStmt] = pStmt;
    }
  }
  if( apVal ){
    int i;







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  sqlite3_stmt *pStmt;

  assert( SizeofArray(azSql)==SizeofArray(p->aStmt) );
  assert( eStmt<SizeofArray(azSql) && eStmt>=0 );
  
  pStmt = p->aStmt[eStmt];
  if( !pStmt ){
    int f = SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_NO_VTAB;
    char *zSql;
    if( eStmt==SQL_CONTENT_INSERT ){
      zSql = sqlite3_mprintf(azSql[eStmt], p->zDb, p->zName, p->zWriteExprlist);
    }else if( eStmt==SQL_SELECT_CONTENT_BY_ROWID ){
      f &= ~SQLITE_PREPARE_NO_VTAB;
      zSql = sqlite3_mprintf(azSql[eStmt], p->zReadExprlist);
    }else{
      zSql = sqlite3_mprintf(azSql[eStmt], p->zDb, p->zName);
    }
    if( !zSql ){
      rc = SQLITE_NOMEM;
    }else{
      rc = sqlite3_prepare_v3(p->db, zSql, -1, f, &pStmt, NULL);

      sqlite3_free(zSql);
      assert( rc==SQLITE_OK || pStmt==0 );
      p->aStmt[eStmt] = pStmt;
    }
  }
  if( apVal ){
    int i;

Changes to ext/fts5/fts5_index.c.

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  Fts5Index *p,
  sqlite3_stmt **ppStmt,
  char *zSql
){
  if( p->rc==SQLITE_OK ){
    if( zSql ){
      p->rc = sqlite3_prepare_v3(p->pConfig->db, zSql, -1,
                                 SQLITE_PREPARE_PERSISTENT, ppStmt, 0);

    }else{
      p->rc = SQLITE_NOMEM;
    }
  }
  sqlite3_free(zSql);
  return p->rc;
}
................................................................................
**
**     DELETE FROM %_data WHERE id BETWEEN $iFirst AND $iLast
*/
static void fts5DataDelete(Fts5Index *p, i64 iFirst, i64 iLast){
  if( p->rc!=SQLITE_OK ) return;

  if( p->pDeleter==0 ){
    int rc;
    Fts5Config *pConfig = p->pConfig;
    char *zSql = sqlite3_mprintf(
        "DELETE FROM '%q'.'%q_data' WHERE id>=? AND id<=?", 
          pConfig->zDb, pConfig->zName
    );
    if( zSql==0 ){
      rc = SQLITE_NOMEM;
    }else{
      rc = sqlite3_prepare_v3(pConfig->db, zSql, -1,
                              SQLITE_PREPARE_PERSISTENT, &p->pDeleter, 0);
      sqlite3_free(zSql);
    }
    if( rc!=SQLITE_OK ){
      p->rc = rc;
      return;
    }
  }

  sqlite3_bind_int64(p->pDeleter, 1, iFirst);
  sqlite3_bind_int64(p->pDeleter, 2, iLast);
  sqlite3_step(p->pDeleter);
  p->rc = sqlite3_reset(p->pDeleter);
}







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  Fts5Index *p,
  sqlite3_stmt **ppStmt,
  char *zSql
){
  if( p->rc==SQLITE_OK ){
    if( zSql ){
      p->rc = sqlite3_prepare_v3(p->pConfig->db, zSql, -1,
          SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_NO_VTAB,
          ppStmt, 0);
    }else{
      p->rc = SQLITE_NOMEM;
    }
  }
  sqlite3_free(zSql);
  return p->rc;
}
................................................................................
**
**     DELETE FROM %_data WHERE id BETWEEN $iFirst AND $iLast
*/
static void fts5DataDelete(Fts5Index *p, i64 iFirst, i64 iLast){
  if( p->rc!=SQLITE_OK ) return;

  if( p->pDeleter==0 ){

    Fts5Config *pConfig = p->pConfig;
    char *zSql = sqlite3_mprintf(
        "DELETE FROM '%q'.'%q_data' WHERE id>=? AND id<=?", 
          pConfig->zDb, pConfig->zName
    );
    if( fts5IndexPrepareStmt(p, &p->pDeleter, zSql) ) return;










  }

  sqlite3_bind_int64(p->pDeleter, 1, iFirst);
  sqlite3_bind_int64(p->pDeleter, 2, iLast);
  sqlite3_step(p->pDeleter);
  p->rc = sqlite3_reset(p->pDeleter);
}

Changes to ext/fts5/fts5_storage.c.

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        zSql = sqlite3_mprintf(azStmt[eStmt], pC->zDb, pC->zName);
        break;
    }

    if( zSql==0 ){
      rc = SQLITE_NOMEM;
    }else{
      rc = sqlite3_prepare_v3(pC->db, zSql, -1,
                              SQLITE_PREPARE_PERSISTENT, &p->aStmt[eStmt], 0);

      sqlite3_free(zSql);
      if( rc!=SQLITE_OK && pzErrMsg ){
        *pzErrMsg = sqlite3_mprintf("%s", sqlite3_errmsg(pC->db));
      }
    }
  }








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        zSql = sqlite3_mprintf(azStmt[eStmt], pC->zDb, pC->zName);
        break;
    }

    if( zSql==0 ){
      rc = SQLITE_NOMEM;
    }else{
      int f = SQLITE_PREPARE_PERSISTENT;
      if( eStmt>FTS5_STMT_LOOKUP ) f |= SQLITE_PREPARE_NO_VTAB;
      rc = sqlite3_prepare_v3(pC->db, zSql, -1, f, &p->aStmt[eStmt], 0);
      sqlite3_free(zSql);
      if( rc!=SQLITE_OK && pzErrMsg ){
        *pzErrMsg = sqlite3_mprintf("%s", sqlite3_errmsg(pC->db));
      }
    }
  }

Changes to src/build.c.

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   && SQLITE_OK!=sqlite3ReadSchema(pParse)
  ){
    return 0;
  }

  p = sqlite3FindTable(db, zName, zDbase);
  if( p==0 ){
    const char *zMsg = flags & LOCATE_VIEW ? "no such view" : "no such table";
#ifndef SQLITE_OMIT_VIRTUALTABLE
    /* If zName is the not the name of a table in the schema created using
    ** CREATE, then check to see if it is the name of an virtual table that
    ** can be an eponymous virtual table. */

    Module *pMod = (Module*)sqlite3HashFind(&db->aModule, zName);
    if( pMod==0 && sqlite3_strnicmp(zName, "pragma_", 7)==0 ){
      pMod = sqlite3PragmaVtabRegister(db, zName);
    }
    if( pMod && sqlite3VtabEponymousTableInit(pParse, pMod) ){
      return pMod->pEpoTab;
    }

#endif
    if( (flags & LOCATE_NOERR)==0 ){







      if( zDbase ){
        sqlite3ErrorMsg(pParse, "%s: %s.%s", zMsg, zDbase, zName);
      }else{
        sqlite3ErrorMsg(pParse, "%s: %s", zMsg, zName);
      }
      pParse->checkSchema = 1;
    }
  }

  return p;
}

/*







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   && SQLITE_OK!=sqlite3ReadSchema(pParse)
  ){
    return 0;
  }

  p = sqlite3FindTable(db, zName, zDbase);
  if( p==0 ){

#ifndef SQLITE_OMIT_VIRTUALTABLE
    /* If zName is the not the name of a table in the schema created using
    ** CREATE, then check to see if it is the name of an virtual table that
    ** can be an eponymous virtual table. */
    if( pParse->disableVtab==0 ){
      Module *pMod = (Module*)sqlite3HashFind(&db->aModule, zName);
      if( pMod==0 && sqlite3_strnicmp(zName, "pragma_", 7)==0 ){
        pMod = sqlite3PragmaVtabRegister(db, zName);
      }
      if( pMod && sqlite3VtabEponymousTableInit(pParse, pMod) ){
        return pMod->pEpoTab;
      }
    }
#endif
    if( flags & LOCATE_NOERR ) return 0;
    pParse->checkSchema = 1;
  }else if( IsVirtual(p) && pParse->disableVtab ){
    p = 0;
  }

  if( p==0 ){
    const char *zMsg = flags & LOCATE_VIEW ? "no such view" : "no such table";
    if( zDbase ){
      sqlite3ErrorMsg(pParse, "%s: %s.%s", zMsg, zDbase, zName);
    }else{
      sqlite3ErrorMsg(pParse, "%s: %s", zMsg, zName);


    }
  }

  return p;
}

/*

Changes to src/prepare.c.

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  /* For a long-term use prepared statement avoid the use of
  ** lookaside memory.
  */
  if( prepFlags & SQLITE_PREPARE_PERSISTENT ){
    sParse.disableLookaside++;
    db->lookaside.bDisable++;
  }


  /* Check to verify that it is possible to get a read lock on all
  ** database schemas.  The inability to get a read lock indicates that
  ** some other database connection is holding a write-lock, which in
  ** turn means that the other connection has made uncommitted changes
  ** to the schema.
  **







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  /* For a long-term use prepared statement avoid the use of
  ** lookaside memory.
  */
  if( prepFlags & SQLITE_PREPARE_PERSISTENT ){
    sParse.disableLookaside++;
    db->lookaside.bDisable++;
  }
  sParse.disableVtab = (prepFlags & SQLITE_PREPARE_NO_VTAB)!=0;

  /* Check to verify that it is possible to get a read lock on all
  ** database schemas.  The inability to get a read lock indicates that
  ** some other database connection is holding a write-lock, which in
  ** turn means that the other connection has made uncommitted changes
  ** to the schema.
  **

Changes to src/sqlite.h.in.

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** [[SQLITE_PREPARE_NORMALIZE]] <dt>SQLITE_PREPARE_NORMALIZE</dt>
** <dd>The SQLITE_PREPARE_NORMALIZE flag is a no-op. This flag used
** to be required for any prepared statement that wanted to use the
** [sqlite3_normalized_sql()] interface.  However, the
** [sqlite3_normalized_sql()] interface is now available to all
** prepared statements, regardless of whether or not they use this
** flag.





** </dl>
*/
#define SQLITE_PREPARE_PERSISTENT              0x01
#define SQLITE_PREPARE_NORMALIZE               0x02


/*
** CAPI3REF: Compiling An SQL Statement
** KEYWORDS: {SQL statement compiler}
** METHOD: sqlite3
** CONSTRUCTOR: sqlite3_stmt
**







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** [[SQLITE_PREPARE_NORMALIZE]] <dt>SQLITE_PREPARE_NORMALIZE</dt>
** <dd>The SQLITE_PREPARE_NORMALIZE flag is a no-op. This flag used
** to be required for any prepared statement that wanted to use the
** [sqlite3_normalized_sql()] interface.  However, the
** [sqlite3_normalized_sql()] interface is now available to all
** prepared statements, regardless of whether or not they use this
** flag.
**
** [[SQLITE_PREPARE_NO_VTAB]] <dt>SQLITE_PREPARE_NO_VTAB</dt>
** <dd>The SQLITE_PREPARE_NO_VTAB flag causes the SQL compiler
** to return an error (error code SQLITE_ERROR) if the statement uses
** any virtual tables.
** </dl>
*/
#define SQLITE_PREPARE_PERSISTENT              0x01
#define SQLITE_PREPARE_NORMALIZE               0x02
#define SQLITE_PREPARE_NO_VTAB                 0x04

/*
** CAPI3REF: Compiling An SQL Statement
** KEYWORDS: {SQL statement compiler}
** METHOD: sqlite3
** CONSTRUCTOR: sqlite3_stmt
**

Changes to src/sqliteInt.h.

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  u8 nested;           /* Number of nested calls to the parser/code generator */
  u8 nTempReg;         /* Number of temporary registers in aTempReg[] */
  u8 isMultiWrite;     /* True if statement may modify/insert multiple rows */
  u8 mayAbort;         /* True if statement may throw an ABORT exception */
  u8 hasCompound;      /* Need to invoke convertCompoundSelectToSubquery() */
  u8 okConstFactor;    /* OK to factor out constants */
  u8 disableLookaside; /* Number of times lookaside has been disabled */

  int nRangeReg;       /* Size of the temporary register block */
  int iRangeReg;       /* First register in temporary register block */
  int nErr;            /* Number of errors seen */
  int nTab;            /* Number of previously allocated VDBE cursors */
  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[] */







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  u8 nested;           /* Number of nested calls to the parser/code generator */
  u8 nTempReg;         /* Number of temporary registers in aTempReg[] */
  u8 isMultiWrite;     /* True if statement may modify/insert multiple rows */
  u8 mayAbort;         /* True if statement may throw an ABORT exception */
  u8 hasCompound;      /* Need to invoke convertCompoundSelectToSubquery() */
  u8 okConstFactor;    /* OK to factor out constants */
  u8 disableLookaside; /* Number of times lookaside has been disabled */
  u8 disableVtab;      /* Disable all virtual tables for this parse */
  int nRangeReg;       /* Size of the temporary register block */
  int iRangeReg;       /* First register in temporary register block */
  int nErr;            /* Number of errors seen */
  int nTab;            /* Number of previously allocated VDBE cursors */
  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[] */

Changes to src/trigger.c.

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  sNC.pParse = pSubParse;
  pSubParse->db = db;
  pSubParse->pTriggerTab = pTab;
  pSubParse->pToplevel = pTop;
  pSubParse->zAuthContext = pTrigger->zName;
  pSubParse->eTriggerOp = pTrigger->op;
  pSubParse->nQueryLoop = pParse->nQueryLoop;


  v = sqlite3GetVdbe(pSubParse);
  if( v ){
    VdbeComment((v, "Start: %s.%s (%s %s%s%s ON %s)", 
      pTrigger->zName, onErrorText(orconf),
      (pTrigger->tr_tm==TRIGGER_BEFORE ? "BEFORE" : "AFTER"),
        (pTrigger->op==TK_UPDATE ? "UPDATE" : ""),







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  sNC.pParse = pSubParse;
  pSubParse->db = db;
  pSubParse->pTriggerTab = pTab;
  pSubParse->pToplevel = pTop;
  pSubParse->zAuthContext = pTrigger->zName;
  pSubParse->eTriggerOp = pTrigger->op;
  pSubParse->nQueryLoop = pParse->nQueryLoop;
  pSubParse->disableVtab = pParse->disableVtab;

  v = sqlite3GetVdbe(pSubParse);
  if( v ){
    VdbeComment((v, "Start: %s.%s (%s %s%s%s ON %s)", 
      pTrigger->zName, onErrorText(orconf),
      (pTrigger->tr_tm==TRIGGER_BEFORE ? "BEFORE" : "AFTER"),
        (pTrigger->op==TK_UPDATE ? "UPDATE" : ""),

Changes to test/fts3aa.test.

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do_execsql_test 9.1 {
  CREATE VIRTUAL TABLE t9 USING fts4(a, "", '---');
}
do_execsql_test 9.2 {
  CREATE VIRTUAL TABLE t10 USING fts3(<, b, c);
}












expand_all_sql db
finish_test







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do_execsql_test 9.1 {
  CREATE VIRTUAL TABLE t9 USING fts4(a, "", '---');
}
do_execsql_test 9.2 {
  CREATE VIRTUAL TABLE t10 USING fts3(<, b, c);
}

do_execsql_test 10.0 {
  CREATE VIRTUAL TABLE z1 USING fts3;
  INSERT INTO z1 VALUES('one two three'),('four one five'),('six two five');
  CREATE TRIGGER z1r1 AFTER DELETE ON z1_content BEGIN
    DELETE FROM z1;
  END;
}
do_catchsql_test 10.1 {
  DELETE FROM z1;
} {1 {SQL logic error}}

expand_all_sql db
finish_test