SQLite

}

/*
** Attempt the transfer optimization on INSERTs of the form
**
**     INSERT INTO tab1 SELECT * FROM tab2;
**
** The xfer optimization transfers raw records from tab2 over to tab1.  
** Columns are not decoded and reassemblied, which greatly improves
** performance.  Raw index records are transferred in the same way.

**
** The xfer optimization is only attempted if tab1 and tab2 are compatible.

** There are lots of rules for determining compatibility - see comments
** embedded in the code for details.
**
** This routine returns TRUE if the optimization is guaranteed to be used.
** Sometimes the xfer optimization will only work if the destination table
** is empty - a factor that can only be determined at run-time.  In that
** case, this routine generates code for the xfer optimization but also
** does a test to see if the destination table is empty and jumps over the
** xfer optimization code if the test fails.  In that case, this routine
** returns FALSE so that the caller will know to go ahead and generate
** an unoptimized transfer.  This routine also returns FALSE if there
** is no chance that the xfer optimization can be applied.




**
** This optimization is particularly useful at making VACUUM run faster.


*/
static int xferOptimization(
  Parse *pParse,        /* Parser context */
  Table *pDest,         /* The table we are inserting into */
  Select *pSelect,      /* A SELECT statement to use as the data source */
  int onError,          /* How to handle constraint errors */
  int iDbDest           /* The database of pDest */

    return 0;   /* tab1 must not be a virtual table */
  }
#endif
  if( onError==OE_Default ){
    if( pDest->iPKey>=0 ) onError = pDest->keyConf;
    if( onError==OE_Default ) onError = OE_Abort;
  }



  assert(pSelect->pSrc);   /* allocated even if there is no FROM clause */
  if( pSelect->pSrc->nSrc!=1 ){
    return 0;   /* FROM clause must have exactly one term */
  }
  if( pSelect->pSrc->a[0].pSelect ){
    return 0;   /* FROM clause cannot contain a subquery */
  }

  ** not worth the effort.  Ticket [6284df89debdfa61db8073e062908af0c9b6118e]
  */
  if( (pParse->db->flags & SQLITE_ForeignKeys)!=0 && pDest->pFKey!=0 ){
    return 0;
  }
#endif
  if( (pParse->db->flags & SQLITE_CountRows)!=0 ){
    return 0;  /* xfer opt does not play well with PRAGMA count_changes */
  }

  /* If we get this far, it means that the xfer optimization is at




  ** least a possibility, though it might only work if the destination
  ** table (tab1) is initially empty.
  */
#ifdef SQLITE_TEST
  sqlite3_xferopt_count++;
#endif
  iDbSrc = sqlite3SchemaToIndex(pParse->db, pSrc->pSchema);
  v = sqlite3GetVdbe(pParse);
  sqlite3CodeVerifySchema(pParse, iDbSrc);
  iSrc = pParse->nTab++;
  iDest = pParse->nTab++;
  regAutoinc = autoIncBegin(pParse, iDbDest, pDest);
  sqlite3OpenTable(pParse, iDest, iDbDest, pDest, OP_OpenWrite);
  if( (pDest->iPKey<0 && pDest->pIndex!=0)          /* (1) */
   || destHasUniqueIdx                              /* (2) */
   || (onError!=OE_Abort && onError!=OE_Rollback)   /* (3) */
  ){
    /* In some circumstances, we are able to run the xfer optimization
    ** only if the destination table is initially empty.  This code makes
    ** that determination.  Conditions under which the destination must
    ** be empty:
    **
    ** (1) There is no INTEGER PRIMARY KEY but there are indices.
    **     (If the destination is not initially empty, the rowid fields

    **     of index entries might need to change.)
    **
    ** (2) The destination has a unique index.  (The xfer optimization 


    **     is unable to test uniqueness.)
    **
    ** (3) onError is something other than OE_Abort and OE_Rollback.
    */
    addr1 = sqlite3VdbeAddOp2(v, OP_Rewind, iDest, 0);
    emptyDestTest = sqlite3VdbeAddOp2(v, OP_Goto, 0, 0);
    sqlite3VdbeJumpHere(v, addr1);
  }else{
    emptyDestTest = 0;
  }

  catchsql {COMMIT}
} {1 {cannot commit - no transaction is active}}
do_test insert4-8.11 {
  execsql {
    SELECT * FROM t1;
  }
} {1 2} 

do_test insert4-8.21 {
  execsql {
    DROP TABLE IF EXISTS t1;
    DROP TABLE IF EXISTS t2;
    CREATE TABLE t1(a INTEGER PRIMARY KEY ON CONFLICT REPLACE, b);
    CREATE TABLE t2(x INTEGER PRIMARY KEY ON CONFLICT REPLACE, y);
    INSERT INTO t2 VALUES(1,3);
    INSERT INTO t1 SELECT * FROM t2;
    SELECT * FROM t1;
  }
} {1 3}
do_test insert4-8.22 {
  execsql {
    DROP TABLE IF EXISTS t1;
    DROP TABLE IF EXISTS t2;
    CREATE TABLE t1(a INTEGER PRIMARY KEY ON CONFLICT IGNORE, b);
    CREATE TABLE t2(x INTEGER PRIMARY KEY ON CONFLICT IGNORE, y);
    INSERT INTO t2 VALUES(1,3);
    INSERT INTO t1 SELECT * FROM t2;
    SELECT * FROM t1;
  }
} {1 3}
do_test insert4-8.23 {
  execsql {
    DROP TABLE IF EXISTS t1;
    DROP TABLE IF EXISTS t2;
    CREATE TABLE t1(a INTEGER PRIMARY KEY ON CONFLICT ABORT, b);
    CREATE TABLE t2(x INTEGER PRIMARY KEY ON CONFLICT ABORT, y);
    INSERT INTO t2 VALUES(1,3);
    INSERT INTO t1 SELECT * FROM t2;
    SELECT * FROM t1;
  }
} {1 3}
do_test insert4-8.24 {
  execsql {
    DROP TABLE IF EXISTS t1;
    DROP TABLE IF EXISTS t2;
    CREATE TABLE t1(a INTEGER PRIMARY KEY ON CONFLICT FAIL, b);
    CREATE TABLE t2(x INTEGER PRIMARY KEY ON CONFLICT FAIL, y);
    INSERT INTO t2 VALUES(1,3);
    INSERT INTO t1 SELECT * FROM t2;
    SELECT * FROM t1;
  }
} {1 3}
do_test insert4-8.25 {
  execsql {
    DROP TABLE IF EXISTS t1;
    DROP TABLE IF EXISTS t2;
    CREATE TABLE t1(a INTEGER PRIMARY KEY ON CONFLICT ROLLBACK, b);
    CREATE TABLE t2(x INTEGER PRIMARY KEY ON CONFLICT ROLLBACK, y);
    INSERT INTO t2 VALUES(1,3);
    INSERT INTO t1 SELECT * FROM t2;
    SELECT * FROM t1;
  }
} {1 3}


finish_test