@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $ PostgreSQL : pgsql / src / backend / storage / page / bufpage . c , v 1.72 2007 / 03 / 02 00 : 48 : 44 tgl Exp $
* $ PostgreSQL : pgsql / src / backend / storage / page / bufpage . c , v 1.73 2007 / 09 / 12 22 : 10 : 26 tgl Exp $
*
* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
*/
@ -99,7 +99,10 @@ PageHeaderIsValid(PageHeader page)
* Add an item to a page . Return value is offset at which it was
* inserted , or InvalidOffsetNumber if there ' s not room to insert .
*
* If offsetNumber is valid and < = current max offset in the page ,
* If overwrite is true , we just store the item at the specified
* offsetNumber ( which must be either a currently - unused item pointer ,
* or one past the last existing item ) . Otherwise ,
* if offsetNumber is valid and < = current max offset in the page ,
* insert item into the array at that position by shuffling ItemId ' s
* down to make room .
* If offsetNumber is not valid , then assign one by finding the first
@ -112,7 +115,7 @@ PageAddItem(Page page,
Item item ,
Size size ,
OffsetNumber offsetNumber ,
ItemIdFlags flags )
bool overwrite )
{
PageHeader phdr = ( PageHeader ) page ;
Size alignedSize ;
@ -121,9 +124,6 @@ PageAddItem(Page page,
ItemId itemId ;
OffsetNumber limit ;
bool needshuffle = false ;
bool overwritemode = ( flags & OverwritePageMode ) ! = 0 ;
flags & = ~ OverwritePageMode ;
/*
* Be wary about corrupted page pointers
@ -146,12 +146,12 @@ PageAddItem(Page page,
if ( OffsetNumberIsValid ( offsetNumber ) )
{
/* yes, check it */
if ( overwritemode )
if ( overwrite )
{
if ( offsetNumber < limit )
{
itemId = PageGetItemId ( phdr , offsetNumber ) ;
if ( ItemIdIsUsed ( itemId ) | | ItemIdGetLength ( itemId ) ! = 0 )
if ( ItemIdIsUsed ( itemId ) | | ItemIdHasStorage ( itemId ) )
{
elog ( WARNING , " will not overwrite a used ItemId " ) ;
return InvalidOffsetNumber ;
@ -170,11 +170,15 @@ PageAddItem(Page page,
/* if no free slot, we'll put it at limit (1st open slot) */
if ( PageHasFreeLinePointers ( phdr ) )
{
/* look for "recyclable" (unused & deallocated) ItemId */
/*
* Look for " recyclable " ( unused ) ItemId . We check for no
* storage as well , just to be paranoid - - - unused items
* should never have storage .
*/
for ( offsetNumber = 1 ; offsetNumber < limit ; offsetNumber + + )
{
itemId = PageGetItemId ( phdr , offsetNumber ) ;
if ( ! ItemIdIsUsed ( itemId ) & & ItemIdGetLength ( itemId ) = = 0 )
if ( ! ItemIdIsUsed ( itemId ) & & ! ItemIdHasStorage ( itemId ) )
break ;
}
if ( offsetNumber > = limit )
@ -224,9 +228,7 @@ PageAddItem(Page page,
( limit - offsetNumber ) * sizeof ( ItemIdData ) ) ;
/* set the item pointer */
itemId - > lp_off = upper ;
itemId - > lp_len = size ;
itemId - > lp_flags = flags ;
ItemIdSetNormal ( itemId , upper , size ) ;
/* copy the item's data onto the page */
memcpy ( ( char * ) page + upper , item , size ) ;
@ -326,6 +328,7 @@ PageRepairFragmentation(Page page, OffsetNumber *unused)
itemidptr ;
ItemId lp ;
int nline ,
nstorage ,
nused ;
int i ;
Size totallen ;
@ -349,38 +352,41 @@ PageRepairFragmentation(Page page, OffsetNumber *unused)
pd_lower , pd_upper , pd_special ) ) ) ;
nline = PageGetMaxOffsetNumber ( page ) ;
nused = 0 ;
nused = nstorage = 0 ;
for ( i = 0 ; i < nline ; i + + )
{
lp = PageGetItemId ( page , i + 1 ) ;
if ( ItemIdDeleted ( lp ) ) /* marked for deletion */
lp - > lp_flags & = ~ ( LP_USED | LP_DELETE ) ;
if ( ItemIdIsUsed ( lp ) )
{
nused + + ;
else if ( unused )
unused [ i - nused ] = ( OffsetNumber ) i ;
if ( ItemIdHasStorage ( lp ) )
nstorage + + ;
}
else
{
/* Unused entries should have lp_len = 0, but make sure */
ItemIdSetUnused ( lp ) ;
/* Report to caller if asked for */
if ( unused )
unused [ i - nused ] = ( OffsetNumber ) i ;
}
}
if ( nused = = 0 )
if ( nstorag e = = 0 )
{
/* Page is completely empty, so just reset it quickly */
for ( i = 0 ; i < nline ; i + + )
{
lp = PageGetItemId ( page , i + 1 ) ;
lp - > lp_len = 0 ; /* indicate unused & deallocated */
}
( ( PageHeader ) page ) - > pd_upper = pd_special ;
}
else
{ /* nu sed != 0 */
{ /* nstorage != 0 */
/* Need to compact the page the hard way */
itemidbase = ( itemIdSort ) palloc ( sizeof ( itemIdSortData ) * nu sed ) ;
itemidbase = ( itemIdSort ) palloc ( sizeof ( itemIdSortData ) * nstorag e ) ;
itemidptr = itemidbase ;
totallen = 0 ;
for ( i = 0 ; i < nline ; i + + )
{
lp = PageGetItemId ( page , i + 1 ) ;
if ( ItemIdIsUsed ( lp ) )
if ( ItemIdHasStorage ( lp ) )
{
itemidptr - > offsetindex = i ;
itemidptr - > itemoff = ItemIdGetOffset ( lp ) ;
@ -394,10 +400,6 @@ PageRepairFragmentation(Page page, OffsetNumber *unused)
totallen + = itemidptr - > alignedlen ;
itemidptr + + ;
}
else
{
lp - > lp_len = 0 ; /* indicate unused & deallocated */
}
}
if ( totallen > ( Size ) ( pd_special - pd_lower ) )
@ -407,13 +409,13 @@ PageRepairFragmentation(Page page, OffsetNumber *unused)
( unsigned int ) totallen , pd_special - pd_lower ) ) ) ;
/* sort itemIdSortData array into decreasing itemoff order */
qsort ( ( char * ) itemidbase , nu sed , sizeof ( itemIdSortData ) ,
qsort ( ( char * ) itemidbase , nstorag e , sizeof ( itemIdSortData ) ,
itemoffcompare ) ;
/* compactify page */
upper = pd_special ;
for ( i = 0 , itemidptr = itemidbase ; i < nu sed ; i + + , itemidptr + + )
for ( i = 0 , itemidptr = itemidbase ; i < nstorag e ; i + + , itemidptr + + )
{
lp = PageGetItemId ( page , itemidptr - > offsetindex + 1 ) ;
upper - = itemidptr - > alignedlen ;
@ -520,6 +522,7 @@ PageIndexTupleDelete(Page page, OffsetNumber offnum)
offidx = offnum - 1 ;
tup = PageGetItemId ( page , offnum ) ;
Assert ( ItemIdHasStorage ( tup ) ) ;
size = ItemIdGetLength ( tup ) ;
offset = ItemIdGetOffset ( tup ) ;
@ -577,6 +580,7 @@ PageIndexTupleDelete(Page page, OffsetNumber offnum)
{
ItemId ii = PageGetItemId ( phdr , i ) ;
Assert ( ItemIdHasStorage ( ii ) ) ;
if ( ItemIdGetOffset ( ii ) < = offset )
ii - > lp_off + = size ;
}
@ -654,6 +658,7 @@ PageIndexMultiDelete(Page page, OffsetNumber *itemnos, int nitems)
for ( offnum = 1 ; offnum < = nline ; offnum + + )
{
lp = PageGetItemId ( page , offnum ) ;
Assert ( ItemIdHasStorage ( lp ) ) ;
size = ItemIdGetLength ( lp ) ;
offset = ItemIdGetOffset ( lp ) ;
if ( offset < pd_upper | |
Tom Lane
19 years ago