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Comment:Do not allow triggers that run as part of REPLACE conflict resolution during an UPDATE to modify the the table being updated. Otherwise, those triggers might delete content out from under the update operation, leading to all kinds of problems. Ticket [314cc133e5ada126]
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SHA3-256: db4b7e1dc399c1f16b827ac087aa37c0815f4b2f41f1ffad59963eead2ab5562
User & Date: drh 2019-12-29 22:08:20
Context
2019-12-30
06:55
In ALTER TABLE, rename columns and tables in expressions that are optimized out by the "AND 0" optimization. Doing this also fixes an otherwise harmless assert() failure. (check-in: a9e0354c user: dan tags: trunk)
2019-12-29
22:08
Do not allow triggers that run as part of REPLACE conflict resolution during an UPDATE to modify the the table being updated. Otherwise, those triggers might delete content out from under the update operation, leading to all kinds of problems. Ticket [314cc133e5ada126] (check-in: db4b7e1d user: drh tags: trunk)
00:52
Add the OP_FinishSeek opcode which completes an OP_DeferredSeek if the seek has not already completed. Also add the sqlite3WhereUsesDeferredSeek() interface to the query planner. The UPDATE implementation adds an OP_FinishSeek before running the final OP_Insert if one is needed. Ticket [ec8abb025e78f40c] and also an assertion fault reported by Yongheng. (check-in: 21ef6e99 user: drh tags: trunk)
Changes
Hide Diffs Unified Diffs Ignore Whitespace Patch

Changes to src/btree.c.

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static int saveCursorPosition(BtCursor *pCur){
  int rc;

  assert( CURSOR_VALID==pCur->eState || CURSOR_SKIPNEXT==pCur->eState );
  assert( 0==pCur->pKey );
  assert( cursorHoldsMutex(pCur) );




  if( pCur->eState==CURSOR_SKIPNEXT ){
    pCur->eState = CURSOR_VALID;
  }else{
    pCur->skipNext = 0;
  }

  rc = saveCursorKey(pCur);
................................................................................
i64 sqlite3BtreeIntegerKey(BtCursor *pCur){
  assert( cursorHoldsMutex(pCur) );
  assert( pCur->eState==CURSOR_VALID );
  assert( pCur->curIntKey );
  getCellInfo(pCur);
  return pCur->info.nKey;
}













#ifdef SQLITE_ENABLE_OFFSET_SQL_FUNC
/*
** Return the offset into the database file for the start of the
** payload to which the cursor is pointing.
*/
i64 sqlite3BtreeOffset(BtCursor *pCur){







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static int saveCursorPosition(BtCursor *pCur){
  int rc;

  assert( CURSOR_VALID==pCur->eState || CURSOR_SKIPNEXT==pCur->eState );
  assert( 0==pCur->pKey );
  assert( cursorHoldsMutex(pCur) );

  if( pCur->curFlags & BTCF_Pinned ){
    return SQLITE_CONSTRAINT_PINNED;
  }
  if( pCur->eState==CURSOR_SKIPNEXT ){
    pCur->eState = CURSOR_VALID;
  }else{
    pCur->skipNext = 0;
  }

  rc = saveCursorKey(pCur);
................................................................................
i64 sqlite3BtreeIntegerKey(BtCursor *pCur){
  assert( cursorHoldsMutex(pCur) );
  assert( pCur->eState==CURSOR_VALID );
  assert( pCur->curIntKey );
  getCellInfo(pCur);
  return pCur->info.nKey;
}

/*
** Pin or unpin a cursor.
*/
void sqlite3BtreeCursorPin(BtCursor *pCur){
  assert( (pCur->curFlags & BTCF_Pinned)==0 );
  pCur->curFlags |= BTCF_Pinned;
}
void sqlite3BtreeCursorUnpin(BtCursor *pCur){
  assert( (pCur->curFlags & BTCF_Pinned)!=0 );
  pCur->curFlags &= ~BTCF_Pinned;
}

#ifdef SQLITE_ENABLE_OFFSET_SQL_FUNC
/*
** Return the offset into the database file for the start of the
** payload to which the cursor is pointing.
*/
i64 sqlite3BtreeOffset(BtCursor *pCur){

Changes to src/btree.h.

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                       int flags, int seekResult);
int sqlite3BtreeFirst(BtCursor*, int *pRes);
int sqlite3BtreeLast(BtCursor*, int *pRes);
int sqlite3BtreeNext(BtCursor*, int flags);
int sqlite3BtreeEof(BtCursor*);
int sqlite3BtreePrevious(BtCursor*, int flags);
i64 sqlite3BtreeIntegerKey(BtCursor*);


#ifdef SQLITE_ENABLE_OFFSET_SQL_FUNC
i64 sqlite3BtreeOffset(BtCursor*);
#endif
int sqlite3BtreePayload(BtCursor*, u32 offset, u32 amt, void*);
const void *sqlite3BtreePayloadFetch(BtCursor*, u32 *pAmt);
u32 sqlite3BtreePayloadSize(BtCursor*);
sqlite3_int64 sqlite3BtreeMaxRecordSize(BtCursor*);







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                       int flags, int seekResult);
int sqlite3BtreeFirst(BtCursor*, int *pRes);
int sqlite3BtreeLast(BtCursor*, int *pRes);
int sqlite3BtreeNext(BtCursor*, int flags);
int sqlite3BtreeEof(BtCursor*);
int sqlite3BtreePrevious(BtCursor*, int flags);
i64 sqlite3BtreeIntegerKey(BtCursor*);
void sqlite3BtreeCursorPin(BtCursor*);
void sqlite3BtreeCursorUnpin(BtCursor*);
#ifdef SQLITE_ENABLE_OFFSET_SQL_FUNC
i64 sqlite3BtreeOffset(BtCursor*);
#endif
int sqlite3BtreePayload(BtCursor*, u32 offset, u32 amt, void*);
const void *sqlite3BtreePayloadFetch(BtCursor*, u32 *pAmt);
u32 sqlite3BtreePayloadSize(BtCursor*);
sqlite3_int64 sqlite3BtreeMaxRecordSize(BtCursor*);

Changes to src/btreeInt.h.

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*/
#define BTCF_WriteFlag    0x01   /* True if a write cursor */
#define BTCF_ValidNKey    0x02   /* True if info.nKey is valid */
#define BTCF_ValidOvfl    0x04   /* True if aOverflow is valid */
#define BTCF_AtLast       0x08   /* Cursor is pointing ot the last entry */
#define BTCF_Incrblob     0x10   /* True if an incremental I/O handle */
#define BTCF_Multiple     0x20   /* Maybe another cursor on the same btree */


/*
** Potential values for BtCursor.eState.
**
** CURSOR_INVALID:
**   Cursor does not point to a valid entry. This can happen (for example) 
**   because the table is empty or because BtreeCursorFirst() has not been







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*/
#define BTCF_WriteFlag    0x01   /* True if a write cursor */
#define BTCF_ValidNKey    0x02   /* True if info.nKey is valid */
#define BTCF_ValidOvfl    0x04   /* True if aOverflow is valid */
#define BTCF_AtLast       0x08   /* Cursor is pointing ot the last entry */
#define BTCF_Incrblob     0x10   /* True if an incremental I/O handle */
#define BTCF_Multiple     0x20   /* Maybe another cursor on the same btree */
#define BTCF_Pinned       0x40   /* Cursor is busy and cannot be moved */

/*
** Potential values for BtCursor.eState.
**
** CURSOR_INVALID:
**   Cursor does not point to a valid entry. This can happen (for example) 
**   because the table is empty or because BtreeCursorFirst() has not been

Changes to src/insert.c.

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        nConflictCk = sqlite3VdbeCurrentAddr(v) - addrConflictCk;
        assert( nConflictCk>0 );
        testcase( nConflictCk>1 );
        if( regTrigCnt ){
          sqlite3MultiWrite(pParse);
          nReplaceTrig++;
        }



        sqlite3GenerateRowDelete(pParse, pTab, pTrigger, iDataCur, iIdxCur,
            regR, nPkField, 0, OE_Replace,
            (pIdx==pPk ? ONEPASS_SINGLE : ONEPASS_OFF), iThisCur);



        if( regTrigCnt ){
          int addrBypass;  /* Jump destination to bypass recheck logic */

          sqlite3VdbeAddOp2(v, OP_AddImm, regTrigCnt, 1); /* incr trigger cnt */
          addrBypass = sqlite3VdbeAddOp0(v, OP_Goto);  /* Bypass recheck */
          VdbeComment((v, "bypass recheck"));








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        nConflictCk = sqlite3VdbeCurrentAddr(v) - addrConflictCk;
        assert( nConflictCk>0 );
        testcase( nConflictCk>1 );
        if( regTrigCnt ){
          sqlite3MultiWrite(pParse);
          nReplaceTrig++;
        }
        if( pTrigger && isUpdate ){
          sqlite3VdbeAddOp1(v, OP_CursorLock, iDataCur);
        }
        sqlite3GenerateRowDelete(pParse, pTab, pTrigger, iDataCur, iIdxCur,
            regR, nPkField, 0, OE_Replace,
            (pIdx==pPk ? ONEPASS_SINGLE : ONEPASS_OFF), iThisCur);
        if( pTrigger && isUpdate ){
          sqlite3VdbeAddOp1(v, OP_CursorUnlock, iDataCur);
        }
        if( regTrigCnt ){
          int addrBypass;  /* Jump destination to bypass recheck logic */

          sqlite3VdbeAddOp2(v, OP_AddImm, regTrigCnt, 1); /* incr trigger cnt */
          addrBypass = sqlite3VdbeAddOp0(v, OP_Goto);  /* Bypass recheck */
          VdbeComment((v, "bypass recheck"));

Changes to src/sqlite.h.in.

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#define SQLITE_CONSTRAINT_FUNCTION     (SQLITE_CONSTRAINT | (4<<8))
#define SQLITE_CONSTRAINT_NOTNULL      (SQLITE_CONSTRAINT | (5<<8))
#define SQLITE_CONSTRAINT_PRIMARYKEY   (SQLITE_CONSTRAINT | (6<<8))
#define SQLITE_CONSTRAINT_TRIGGER      (SQLITE_CONSTRAINT | (7<<8))
#define SQLITE_CONSTRAINT_UNIQUE       (SQLITE_CONSTRAINT | (8<<8))
#define SQLITE_CONSTRAINT_VTAB         (SQLITE_CONSTRAINT | (9<<8))
#define SQLITE_CONSTRAINT_ROWID        (SQLITE_CONSTRAINT |(10<<8))

#define SQLITE_NOTICE_RECOVER_WAL      (SQLITE_NOTICE | (1<<8))
#define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8))
#define SQLITE_WARNING_AUTOINDEX       (SQLITE_WARNING | (1<<8))
#define SQLITE_AUTH_USER               (SQLITE_AUTH | (1<<8))
#define SQLITE_OK_LOAD_PERMANENTLY     (SQLITE_OK | (1<<8))
#define SQLITE_OK_SYMLINK              (SQLITE_OK | (2<<8))








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#define SQLITE_CONSTRAINT_FUNCTION     (SQLITE_CONSTRAINT | (4<<8))
#define SQLITE_CONSTRAINT_NOTNULL      (SQLITE_CONSTRAINT | (5<<8))
#define SQLITE_CONSTRAINT_PRIMARYKEY   (SQLITE_CONSTRAINT | (6<<8))
#define SQLITE_CONSTRAINT_TRIGGER      (SQLITE_CONSTRAINT | (7<<8))
#define SQLITE_CONSTRAINT_UNIQUE       (SQLITE_CONSTRAINT | (8<<8))
#define SQLITE_CONSTRAINT_VTAB         (SQLITE_CONSTRAINT | (9<<8))
#define SQLITE_CONSTRAINT_ROWID        (SQLITE_CONSTRAINT |(10<<8))
#define SQLITE_CONSTRAINT_PINNED       (SQLITE_CONSTRAINT |(11<<8))
#define SQLITE_NOTICE_RECOVER_WAL      (SQLITE_NOTICE | (1<<8))
#define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8))
#define SQLITE_WARNING_AUTOINDEX       (SQLITE_WARNING | (1<<8))
#define SQLITE_AUTH_USER               (SQLITE_AUTH | (1<<8))
#define SQLITE_OK_LOAD_PERMANENTLY     (SQLITE_OK | (1<<8))
#define SQLITE_OK_SYMLINK              (SQLITE_OK | (2<<8))

Changes to src/vdbe.c.

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  if( !pOp->p1 ){
    sqlite3ExpirePreparedStatements(db, pOp->p2);
  }else{
    p->expired = pOp->p2+1;
  }
  break;
}































#ifndef SQLITE_OMIT_SHARED_CACHE
/* Opcode: TableLock P1 P2 P3 P4 *
** Synopsis: iDb=P1 root=P2 write=P3
**
** Obtain a lock on a particular table. This instruction is only used when
** the shared-cache feature is enabled. 







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  if( !pOp->p1 ){
    sqlite3ExpirePreparedStatements(db, pOp->p2);
  }else{
    p->expired = pOp->p2+1;
  }
  break;
}

/* Opcode: CursorLock P1 * * * *
**
** Lock the btree to which cursor P1 is pointing so that the btree cannot be
** written by an other cursor.
*/
case OP_CursorLock: {
  VdbeCursor *pC;
  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  pC = p->apCsr[pOp->p1];
  assert( pC!=0 );
  assert( pC->eCurType==CURTYPE_BTREE );
  sqlite3BtreeCursorPin(pC->uc.pCursor);
  break;
}

/* Opcode: CursorUnlock P1 * * * *
**
** Unlock the btree to which cursor P1 is pointing so that it can be
** written by other cursors.
*/
case OP_CursorUnlock: {
  VdbeCursor *pC;
  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  pC = p->apCsr[pOp->p1];
  assert( pC!=0 );
  assert( pC->eCurType==CURTYPE_BTREE );
  sqlite3BtreeCursorUnpin(pC->uc.pCursor);
  break;
}

#ifndef SQLITE_OMIT_SHARED_CACHE
/* Opcode: TableLock P1 P2 P3 P4 *
** Synopsis: iDb=P1 root=P2 write=P3
**
** Obtain a lock on a particular table. This instruction is only used when
** the shared-cache feature is enabled. 

Changes to test/conflict3.test.

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      DELETE FROM t0; 
    END;

    INSERT INTO t0 VALUES(1, NULL);
    INSERT INTO t0 VALUES(0, NULL);
  }

  do_execsql_test 13.1.1 {
    UPDATE OR REPLACE t0 SET c1 = 1;
  }

  integrity_check 13.1.2

  do_execsql_test 13.1.3 {
    SELECT * FROM t0
  } {}

  do_execsql_test 13.2.0 {
    CREATE TABLE t2 (a PRIMARY KEY, b UNIQUE, c UNIQUE) WITHOUT ROWID;
    CREATE TRIGGER tr3 AFTER DELETE ON t2 BEGIN 
      DELETE FROM t2; 
    END;

    INSERT INTO t2 VALUES(1, 1, 1);
    INSERT INTO t2 VALUES(2, 2, 2);
  }

  do_execsql_test 13.2.1 {
    UPDATE OR REPLACE t2 SET c = 0;
  }

  integrity_check 13.2.2

  do_execsql_test 13.2.3 {
    SELECT * FROM t2
  } {}

  do_execsql_test 13.3.0 {
    CREATE TABLE t1(a, b);
    CREATE TABLE log(x);
    CREATE INDEX i1 ON t1(a);
    INSERT INTO t1 VALUES(1, 2);








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      DELETE FROM t0; 
    END;

    INSERT INTO t0 VALUES(1, NULL);
    INSERT INTO t0 VALUES(0, NULL);
  }

  do_catchsql_test 13.1.1 {
    UPDATE OR REPLACE t0 SET c1 = 1;
  } {1 {constraint failed}}

  integrity_check 13.1.2

  do_execsql_test 13.1.3 {
    SELECT * FROM t0
  } {1 {} 0 {}}

  do_execsql_test 13.2.0 {
    CREATE TABLE t2 (a PRIMARY KEY, b UNIQUE, c UNIQUE) WITHOUT ROWID;
    CREATE TRIGGER tr3 AFTER DELETE ON t2 BEGIN 
      DELETE FROM t2; 
    END;

    INSERT INTO t2 VALUES(1, 1, 1);
    INSERT INTO t2 VALUES(2, 2, 2);
  }

  do_catchsql_test 13.2.1 {
    UPDATE OR REPLACE t2 SET c = 0;
  } {1 {constraint failed}}

  integrity_check 13.2.2

  do_execsql_test 13.2.3 {
    SELECT * FROM t2
  } {1 1 1 2 2 2}

  do_execsql_test 13.3.0 {
    CREATE TABLE t1(a, b);
    CREATE TABLE log(x);
    CREATE INDEX i1 ON t1(a);
    INSERT INTO t1 VALUES(1, 2);

Changes to test/update.test.

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   a TEXT,
   b INTEGER PRIMARY KEY UNIQUE
  ); 
  INSERT INTO t1 VALUES(1,2);
  UPDATE t1 SET a = quote(b) WHERE b>=2;
  SELECT * FROM t1;
} {2 2}






























finish_test








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   a TEXT,
   b INTEGER PRIMARY KEY UNIQUE
  ); 
  INSERT INTO t1 VALUES(1,2);
  UPDATE t1 SET a = quote(b) WHERE b>=2;
  SELECT * FROM t1;
} {2 2}

# 2019-12-29 ticket https://www.sqlite.org/src/info/314cc133e5ada126
# REPLACE conflict resolution during an UPDATE causes a DELETE trigger 
# to fire.  If that DELETE trigger subsequently modifies the row
# being updated, bad things can happen.  Prevent this by prohibiting
# triggers from making changes to the table being updated while doing
# REPLACE conflict resolution on the UPDATE.
#
# See also tickets:
#   https://www.sqlite.org/src/info/c1e19e12046d23fe 2019-10-25
#   https://www.sqlite.org/src/info/a8a4847a2d96f5de 2019-10-16 
#
reset_db
do_execsql_test update-20.10 {
  PRAGMA recursive_triggers = true;
  CREATE TABLE t1(a UNIQUE ON CONFLICT REPLACE, b);
  INSERT INTO t1(a,b) VALUES(4,12),(9,13);
  CREATE INDEX i0 ON t1(b);
  CREATE TRIGGER tr0 DELETE ON t1 BEGIN
    UPDATE t1 SET b = a;
  END;
  PRAGMA integrity_check;
} {ok}
do_catchsql_test update-20.20 {
  UPDATE t1 SET a=0;
} {1 {constraint failed}}
do_execsql_test update-20.30 {
  PRAGMA integrity_check;
} {ok}

finish_test