Fix oversight in collecting values for cleanup_info records.

vacuum_log_cleanup_info() now generates log records with a valid
latestRemovedXid set in all cases. Also be careful not to zero the
value when we do a round of vacuuming part-way through lazy_scan_heap().
Incidentally, this reduces frequency of conflicts in Hot Standby.

diff --git a/src/backend/access/heap/pruneheap.c b/src/backend/access/heap/pruneheap.c
index 89607f5..0fee284 100644 (file)
--- a/src/backend/access/heap/pruneheap.c
+++ b/src/backend/access/heap/pruneheap.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/access/heap/pruneheap.c,v 1.22 2010/02/26 02:00:33 momjian Exp $
+ *       $PostgreSQL: pgsql/src/backend/access/heap/pruneheap.c,v 1.23 2010/04/21 17:20:56 sriggs Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -122,8 +122,10 @@ heap_page_prune_opt(Relation relation, Buffer buffer, TransactionId OldestXmin)
                 */
                if (PageIsFull(page) || PageGetHeapFreeSpace(page) < minfree)
                {
+                       TransactionId ignore = InvalidTransactionId;    /* return value not needed */
+
                        /* OK to prune */
-                       (void) heap_page_prune(relation, buffer, OldestXmin, true);
+                       (void) heap_page_prune(relation, buffer, OldestXmin, true, &ignore);
                }
 
                /* And release buffer lock */
@@ -145,11 +147,12 @@ heap_page_prune_opt(Relation relation, Buffer buffer, TransactionId OldestXmin)
  * send its own new total to pgstats, and we don't want this delta applied
  * on top of that.)
  *
- * Returns the number of tuples deleted from the page.
+ * Returns the number of tuples deleted from the page and sets
+ * latestRemovedXid.
  */
 int
 heap_page_prune(Relation relation, Buffer buffer, TransactionId OldestXmin,
-                               bool report_stats)
+                               bool report_stats, TransactionId *latestRemovedXid)
 {
        int                     ndeleted = 0;
        Page            page = BufferGetPage(buffer);
@@ -273,6 +276,8 @@ heap_page_prune(Relation relation, Buffer buffer, TransactionId OldestXmin,
        if (report_stats && ndeleted > prstate.ndead)
                pgstat_update_heap_dead_tuples(relation, ndeleted - prstate.ndead);
 
+       *latestRemovedXid = prstate.latestRemovedXid;
+
        /*
         * XXX Should we update the FSM information of this page ?
         *

diff --git a/src/backend/commands/vacuumlazy.c b/src/backend/commands/vacuumlazy.c
index 1cf1ae3..6e807e3 100644 (file)
--- a/src/backend/commands/vacuumlazy.c
+++ b/src/backend/commands/vacuumlazy.c
@@ -29,7 +29,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/commands/vacuumlazy.c,v 1.132 2010/02/26 02:00:40 momjian Exp $
+ *       $PostgreSQL: pgsql/src/backend/commands/vacuumlazy.c,v 1.133 2010/04/21 17:20:56 sriggs Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -274,6 +274,8 @@ vacuum_log_cleanup_info(Relation rel, LVRelStats *vacrelstats)
        if (rel->rd_istemp || !XLogIsNeeded())
                return;
 
+       Assert(TransactionIdIsValid(vacrelstats->latestRemovedXid));
+
        (void) log_heap_cleanup_info(rel->rd_node, vacrelstats->latestRemovedXid);
 }
 
@@ -395,9 +397,11 @@ lazy_scan_heap(Relation onerel, LVRelStats *vacrelstats,
                                                                  vacrelstats);
                        /* Remove tuples from heap */
                        lazy_vacuum_heap(onerel, vacrelstats);
-                       /* Forget the now-vacuumed tuples, and press on */
+                       /*
+                        * Forget the now-vacuumed tuples, and press on, but be careful
+                        * not to reset latestRemovedXid since we want that value to be valid.
+                        */
                        vacrelstats->num_dead_tuples = 0;
-                       vacrelstats->latestRemovedXid = InvalidTransactionId;
                        vacrelstats->num_index_scans++;
                }
 
@@ -484,8 +488,8 @@ lazy_scan_heap(Relation onerel, LVRelStats *vacrelstats,
                 *
                 * We count tuples removed by the pruning step as removed by VACUUM.
                 */
-               tups_vacuumed += heap_page_prune(onerel, buf, OldestXmin, false);
-
+               tups_vacuumed += heap_page_prune(onerel, buf, OldestXmin, false,
+                                                                                                       &vacrelstats->latestRemovedXid);
                /*
                 * Now scan the page to collect vacuumable items and check for tuples
                 * requiring freezing.
@@ -676,9 +680,12 @@ lazy_scan_heap(Relation onerel, LVRelStats *vacrelstats,
                {
                        /* Remove tuples from heap */
                        lazy_vacuum_page(onerel, blkno, buf, 0, vacrelstats);
-                       /* Forget the now-vacuumed tuples, and press on */
+                       /*
+                        * Forget the now-vacuumed tuples, and press on, but be careful
+                        * not to reset latestRemovedXid since we want that value to be valid.
+                        */
+                       Assert(TransactionIdIsValid(vacrelstats->latestRemovedXid));
                        vacrelstats->num_dead_tuples = 0;
-                       vacrelstats->latestRemovedXid = InvalidTransactionId;
                        vacuumed_pages++;
                }
 

diff --git a/src/include/access/heapam.h b/src/include/access/heapam.h
index 1f26b37..521f958 100644 (file)
--- a/src/include/access/heapam.h
+++ b/src/include/access/heapam.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/access/heapam.h,v 1.148 2010/02/26 02:01:20 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/access/heapam.h,v 1.149 2010/04/21 17:20:56 sriggs Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -144,7 +144,7 @@ extern void heap_page_prune_opt(Relation relation, Buffer buffer,
                                        TransactionId OldestXmin);
 extern int heap_page_prune(Relation relation, Buffer buffer,
                                TransactionId OldestXmin,
-                               bool report_stats);
+                               bool report_stats, TransactionId *latestRemovedXid);
 extern void heap_page_prune_execute(Buffer buffer,
                                                OffsetNumber *redirected, int nredirected,
                                                OffsetNumber *nowdead, int ndead,