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

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.

2 files changed, 8 insertions, 27 deletions

diff --git a/src/backend/storage/page/bufpage.c b/src/backend/storage/page/bufpage.c
index 8f8ba9e0d2b..5b3f7bee95f 100644
--- a/src/backend/storage/page/bufpage.c
+++ b/src/backend/storage/page/bufpage.c
@@ -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);
 }
 
@@ -532,13 +526,6 @@ PageIndexTupleDelete(Page page, OffsetNumber offnum)
 	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.
 	 *
 	 * Anything that used to be before the deleted tuple's data was moved
@@ -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);
 }
diff --git a/src/backend/storage/smgr/smgr.c b/src/backend/storage/smgr/smgr.c
index ca171a3b1a2..13ad72a3755 100644
--- a/src/backend/storage/smgr/smgr.c
+++ b/src/backend/storage/smgr/smgr.c
@@ -11,7 +11,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/storage/smgr/smgr.c,v 1.88 2005/06/06 17:01:24 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/storage/smgr/smgr.c,v 1.89 2005/06/06 20:22:58 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -370,9 +370,9 @@ smgrcreate(SMgrRelation reln, bool isTemp, bool isRedo)
 	 */
 	xlrec.rnode = reln->smgr_rnode;
 
-	rdata.buffer = InvalidBuffer;
 	rdata.data = (char *) &xlrec;
 	rdata.len = sizeof(xlrec);
+	rdata.buffer = InvalidBuffer;
 	rdata.next = NULL;
 
 	lsn = XLogInsert(RM_SMGR_ID, XLOG_SMGR_CREATE | XLOG_NO_TRAN, &rdata);
@@ -635,9 +635,9 @@ smgrtruncate(SMgrRelation reln, BlockNumber nblocks, bool isTemp)
 		xlrec.blkno = newblks;
 		xlrec.rnode = reln->smgr_rnode;
 
-		rdata.buffer = InvalidBuffer;
 		rdata.data = (char *) &xlrec;
 		rdata.len = sizeof(xlrec);
+		rdata.buffer = InvalidBuffer;
 		rdata.next = NULL;
 
 		lsn = XLogInsert(RM_SMGR_ID, XLOG_SMGR_TRUNCATE | XLOG_NO_TRAN,