@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $ PostgreSQL : pgsql / src / backend / access / nbtree / nbtutils . c , v 1.94 2009 / 10 / 08 22 : 34 : 57 tgl Exp $
* $ PostgreSQL : pgsql / src / backend / access / nbtree / nbtutils . c , v 1.95 2010 / 01 / 01 21 : 53 : 49 tgl Exp $
*
* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
*/
@ -276,6 +276,11 @@ _bt_preprocess_keys(IndexScanDesc scan)
* in any particular strategy in this case , so set it to
* BTEqualStrategyNumber - - - we can treat IS NULL as an equality
* operator for purposes of search strategy .
*
* Likewise , " x IS NOT NULL " is supported . We treat that as either
* " less than NULL " in a NULLS LAST index , or " greater than NULL "
* in a NULLS FIRST index . However , we have to flip those around in
* a DESC index , to allow for the re - flipping that occurs elsewhere .
*/
if ( cur - > sk_flags & SK_ISNULL )
{
@ -284,6 +289,21 @@ _bt_preprocess_keys(IndexScanDesc scan)
cur - > sk_strategy = BTEqualStrategyNumber ;
cur - > sk_subtype = InvalidOid ;
}
else if ( cur - > sk_flags & SK_SEARCHNOTNULL )
{
switch ( indoption [ cur - > sk_attno - 1 ] &
( INDOPTION_DESC | INDOPTION_NULLS_FIRST ) )
{
case 0 : /* ASC / NULLS LAST */
case INDOPTION_DESC | INDOPTION_NULLS_FIRST :
cur - > sk_strategy = BTLessStrategyNumber ;
break ;
default :
cur - > sk_strategy = BTGreaterStrategyNumber ;
break ;
}
cur - > sk_subtype = InvalidOid ;
}
else
so - > qual_ok = false ;
}
@ -320,7 +340,7 @@ _bt_preprocess_keys(IndexScanDesc scan)
{
if ( i < numberOfKeys )
{
/* See comments above about NULLs and IS NULL handling. */
/* See comments above about NULLs and IS NULL/NOT NULL handling */
/* Note: we assume SK_ISNULL is never set in a row header key */
if ( cur - > sk_flags & SK_ISNULL )
{
@ -329,6 +349,21 @@ _bt_preprocess_keys(IndexScanDesc scan)
cur - > sk_strategy = BTEqualStrategyNumber ;
cur - > sk_subtype = InvalidOid ;
}
else if ( cur - > sk_flags & SK_SEARCHNOTNULL )
{
switch ( indoption [ cur - > sk_attno - 1 ] &
( INDOPTION_DESC | INDOPTION_NULLS_FIRST ) )
{
case 0 : /* ASC / NULLS LAST */
case INDOPTION_DESC | INDOPTION_NULLS_FIRST :
cur - > sk_strategy = BTLessStrategyNumber ;
break ;
default :
cur - > sk_strategy = BTGreaterStrategyNumber ;
break ;
}
cur - > sk_subtype = InvalidOid ;
}
else
{
so - > qual_ok = false ;
@ -365,13 +400,6 @@ _bt_preprocess_keys(IndexScanDesc scan)
if ( ! chk | | j = = ( BTEqualStrategyNumber - 1 ) )
continue ;
/* IS NULL together with any other predicate must fail */
if ( eq - > sk_flags & SK_SEARCHNULL )
{
so - > qual_ok = false ;
return ;
}
if ( _bt_compare_scankey_args ( scan , chk , eq , chk ,
& test_result ) )
{
@ -484,23 +512,6 @@ _bt_preprocess_keys(IndexScanDesc scan)
else
{
/* yup, keep only the more restrictive key */
/* if either arg is NULL, don't try to compare */
if ( ( cur - > sk_flags | xform [ j ] - > sk_flags ) & SK_ISNULL )
{
/* at least one of them must be an IS NULL clause */
Assert ( j = = ( BTEqualStrategyNumber - 1 ) ) ;
Assert ( ( cur - > sk_flags | xform [ j ] - > sk_flags ) & SK_SEARCHNULL ) ;
/* if one is and one isn't, the search must fail */
if ( ( cur - > sk_flags ^ xform [ j ] - > sk_flags ) & SK_SEARCHNULL )
{
so - > qual_ok = false ;
return ;
}
/* we have duplicate IS NULL clauses, ignore the newer one */
continue ;
}
if ( _bt_compare_scankey_args ( scan , cur , cur , xform [ j ] ,
& test_result ) )
{
@ -534,8 +545,7 @@ _bt_preprocess_keys(IndexScanDesc scan)
}
/*
* Compare two scankey values using a specified operator . Both values
* must be already known non - NULL .
* Compare two scankey values using a specified operator .
*
* The test we want to perform is logically " leftarg op rightarg " , where
* leftarg and rightarg are the sk_argument values in those ScanKeys , and
@ -555,8 +565,7 @@ _bt_preprocess_keys(IndexScanDesc scan)
*
* Note : this routine needs to be insensitive to any DESC option applied
* to the index column . For example , " x < 4 " is a tighter constraint than
* " x < 5 " regardless of which way the index is sorted . We don ' t worry about
* NULLS FIRST / LAST either , since the given values are never nulls .
* " x < 5 " regardless of which way the index is sorted .
*/
static bool
_bt_compare_scankey_args ( IndexScanDesc scan , ScanKey op ,
@ -571,6 +580,64 @@ _bt_compare_scankey_args(IndexScanDesc scan, ScanKey op,
cmp_op ;
StrategyNumber strat ;
/*
* First , deal with cases where one or both args are NULL . This should
* only happen when the scankeys represent IS NULL / NOT NULL conditions .
*/
if ( ( leftarg - > sk_flags | rightarg - > sk_flags ) & SK_ISNULL )
{
bool leftnull ,
rightnull ;
if ( leftarg - > sk_flags & SK_ISNULL )
{
Assert ( leftarg - > sk_flags & ( SK_SEARCHNULL | SK_SEARCHNOTNULL ) ) ;
leftnull = true ;
}
else
leftnull = false ;
if ( rightarg - > sk_flags & SK_ISNULL )
{
Assert ( rightarg - > sk_flags & ( SK_SEARCHNULL | SK_SEARCHNOTNULL ) ) ;
rightnull = true ;
}
else
rightnull = false ;
/*
* We treat NULL as either greater than or less than all other values .
* Since true > false , the tests below work correctly for NULLS LAST
* logic . If the index is NULLS FIRST , we need to flip the strategy .
*/
strat = op - > sk_strategy ;
if ( op - > sk_flags & SK_BT_NULLS_FIRST )
strat = BTCommuteStrategyNumber ( strat ) ;
switch ( strat )
{
case BTLessStrategyNumber :
* result = ( leftnull < rightnull ) ;
break ;
case BTLessEqualStrategyNumber :
* result = ( leftnull < = rightnull ) ;
break ;
case BTEqualStrategyNumber :
* result = ( leftnull = = rightnull ) ;
break ;
case BTGreaterEqualStrategyNumber :
* result = ( leftnull > = rightnull ) ;
break ;
case BTGreaterStrategyNumber :
* result = ( leftnull > rightnull ) ;
break ;
default :
elog ( ERROR , " unrecognized StrategyNumber: %d " , ( int ) strat ) ;
* result = false ; /* keep compiler quiet */
break ;
}
return true ;
}
/*
* The opfamily we need to worry about is identified by the index column .
*/
@ -844,11 +911,18 @@ _bt_checkkeys(IndexScanDesc scan,
if ( key - > sk_flags & SK_ISNULL )
{
/* Handle IS NULL tests */
Assert ( key - > sk_flags & SK_SEARCHNULL ) ;
if ( isNull )
continue ; /* tuple satisfies this qual */
/* Handle IS NULL/NOT NULL tests */
if ( key - > sk_flags & SK_SEARCHNULL )
{
if ( isNull )
continue ; /* tuple satisfies this qual */
}
else
{
Assert ( key - > sk_flags & SK_SEARCHNOTNULL ) ;
if ( ! isNull )
continue ; /* tuple satisfies this qual */
}
/*
* Tuple fails this qual . If it ' s a required qual for the current
Tom Lane
16 years ago