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Modify XLogInsert API to make callers specify whether pages to be backed

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up have the standard layout with unused space between pd_lower and pd_upper.
When this is set, XLogInsert will omit the unused space without bothering
to scan it to see if it's zero.  That saves time in XLogInsert, and also
allows reversion of my earlier patch to make PageRepairFragmentation et al
explicitly re-zero freed space.  Per suggestion by Heikki Linnakangas.
This commit is contained in:
Tom Lane
2005-06-06 20:22:58 +00:00
parent 4c8495a1f2
commit ee7ac7b11e
14 changed files with 185 additions and 156 deletions
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29
src/backend/storage/page/bufpage.c
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@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/storage/page/bufpage.c,v 1.64 2005/06/02 05:55:28 tgl Exp $
* $PostgreSQL: pgsql/src/backend/storage/page/bufpage.c,v 1.65 2005/06/06 20:22:58 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -357,7 +357,7 @@ PageRepairFragmentation(Page page, OffsetNumber *unused)
lp = PageGetItemId(page, i + 1);
lp->lp_len = 0; /* indicate unused & deallocated */
}
((PageHeader) page)->pd_upper = pd_upper = pd_special;
((PageHeader) page)->pd_upper = pd_special;
}
else
{ /* nused != 0 */
@@ -411,17 +411,11 @@ PageRepairFragmentation(Page page, OffsetNumber *unused)
lp->lp_off = upper;
}
((PageHeader) page)->pd_upper = pd_upper = upper;
((PageHeader) page)->pd_upper = upper;
pfree(itemidbase);
}
/*
* Zero out the now-free space. This is not essential, but it allows
* xlog.c to compress WAL data better.
*/
MemSet((char *) page + pd_lower, 0, pd_upper - pd_lower);
return (nline - nused);
}
@@ -531,13 +525,6 @@ PageIndexTupleDelete(Page page, OffsetNumber offnum)
phdr->pd_upper += size;
phdr->pd_lower -= sizeof(ItemIdData);
/*
* Zero out the just-freed space. This is not essential, but it allows
* xlog.c to compress WAL data better.
*/
MemSet((char *) page + phdr->pd_lower, 0, sizeof(ItemIdData));
MemSet(addr, 0, size);
/*
* Finally, we need to adjust the linp entries that remain.
*
@@ -685,14 +672,8 @@ PageIndexMultiDelete(Page page, OffsetNumber *itemnos, int nitems)
lp->lp_off = upper;
}
phdr->pd_lower = pd_lower = SizeOfPageHeaderData + nused * sizeof(ItemIdData);
phdr->pd_upper = pd_upper = upper;
/*
* Zero out the now-free space. This is not essential, but it allows
* xlog.c to compress WAL data better.
*/
MemSet((char *) page + pd_lower, 0, pd_upper - pd_lower);
phdr->pd_lower = SizeOfPageHeaderData + nused * sizeof(ItemIdData);
phdr->pd_upper = upper;
pfree(itemidbase);
}