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authorAlvaro Herrera2007-05-18 23:19:42 +0000
committerAlvaro Herrera2007-05-18 23:19:42 +0000
commit4147ac7cc11abbe2b2215e590b2b8c0cb6dd1938 (patch)
tree4829e9d62d7f86c355ccf83fff76f44db4c0d6f1
parent6dce35146adf66f05b6b8366262a9233af1609f8 (diff)
Have CLUSTER advance the table's relfrozenxid. The new frozen point is the
FreezeXid introduced in a recent commit, so there isn't any data loss in this approach. Doing it causes ALTER TABLE (or rather, the forms of it that cause a full table rewrite) to be affected as well. In this case, the frozen point is RecentXmin, because after the rewrite all the tuples are relabeled with the rewriting transaction's Xid. TOAST tables are fixed automatically as well, as fallout of the way they were already being handled in the respective code paths. With this patch, there is no longer need to VACUUM tables for Xid wraparound purposes that have been cleaned up via TRUNCATE or CLUSTER.
-rw-r--r--src/backend/commands/cluster.c27
-rw-r--r--src/backend/commands/tablecmds.c9
-rw-r--r--src/include/commands/cluster.h2
3 files changed, 29 insertions, 9 deletions
diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index 781ce7e817..11ae4e113f 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -55,7 +55,7 @@ typedef struct
static void cluster_rel(RelToCluster *rv, bool recheck);
static void rebuild_relation(Relation OldHeap, Oid indexOid);
-static void copy_heap_data(Oid OIDNewHeap, Oid OIDOldHeap, Oid OIDOldIndex);
+static TransactionId copy_heap_data(Oid OIDNewHeap, Oid OIDOldHeap, Oid OIDOldIndex);
static List *get_tables_to_cluster(MemoryContext cluster_context);
@@ -513,6 +513,7 @@ rebuild_relation(Relation OldHeap, Oid indexOid)
Oid tableSpace = OldHeap->rd_rel->reltablespace;
Oid OIDNewHeap;
char NewHeapName[NAMEDATALEN];
+ TransactionId frozenXid;
ObjectAddress object;
/* Mark the correct index as clustered */
@@ -539,13 +540,13 @@ rebuild_relation(Relation OldHeap, Oid indexOid)
/*
* Copy the heap data into the new table in the desired order.
*/
- copy_heap_data(OIDNewHeap, tableOid, indexOid);
+ frozenXid = copy_heap_data(OIDNewHeap, tableOid, indexOid);
/* To make the new heap's data visible (probably not needed?). */
CommandCounterIncrement();
/* Swap the physical files of the old and new heaps. */
- swap_relation_files(tableOid, OIDNewHeap);
+ swap_relation_files(tableOid, OIDNewHeap, frozenXid);
CommandCounterIncrement();
@@ -641,9 +642,10 @@ make_new_heap(Oid OIDOldHeap, const char *NewName, Oid NewTableSpace)
}
/*
- * Do the physical copying of heap data.
+ * Do the physical copying of heap data. Returns the TransactionId used as
+ * freeze cutoff point for the tuples.
*/
-static void
+static TransactionId
copy_heap_data(Oid OIDNewHeap, Oid OIDOldHeap, Oid OIDOldIndex)
{
Relation NewHeap,
@@ -816,6 +818,8 @@ copy_heap_data(Oid OIDNewHeap, Oid OIDOldHeap, Oid OIDOldIndex)
index_close(OldIndex, NoLock);
heap_close(OldHeap, NoLock);
heap_close(NewHeap, NoLock);
+
+ return FreezeXid;
}
/*
@@ -826,9 +830,16 @@ copy_heap_data(Oid OIDNewHeap, Oid OIDOldHeap, Oid OIDOldIndex)
*
* Also swap any TOAST links, so that the toast data moves along with
* the main-table data.
+ *
+ * Additionally, the first relation is marked with relfrozenxid set to
+ * frozenXid. It seems a bit ugly to have this here, but all callers would
+ * have to do it anyway, so having it here saves a heap_update. Note: the
+ * TOAST table needs no special handling, because since we swapped the links,
+ * the entry for the TOAST table will now contain RecentXmin in relfrozenxid,
+ * which is the correct value.
*/
void
-swap_relation_files(Oid r1, Oid r2)
+swap_relation_files(Oid r1, Oid r2, TransactionId frozenXid)
{
Relation relRelation;
HeapTuple reltup1,
@@ -872,6 +883,10 @@ swap_relation_files(Oid r1, Oid r2)
/* we should not swap reltoastidxid */
+ /* set rel1's frozen Xid */
+ Assert(TransactionIdIsNormal(frozenXid));
+ relform1->relfrozenxid = frozenXid;
+
/* swap size statistics too, since new rel has freshly-updated stats */
{
int4 swap_pages;
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 9f1aac1cd0..db77baba9f 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -2285,8 +2285,13 @@ ATRewriteTables(List **wqueue)
*/
ATRewriteTable(tab, OIDNewHeap);
- /* Swap the physical files of the old and new heaps. */
- swap_relation_files(tab->relid, OIDNewHeap);
+ /*
+ * Swap the physical files of the old and new heaps. Since we are
+ * generating a new heap, we can use RecentXmin for the table's new
+ * relfrozenxid because we rewrote all the tuples on
+ * ATRewriteTable, so no older Xid remains on the table.
+ */
+ swap_relation_files(tab->relid, OIDNewHeap, RecentXmin);
CommandCounterIncrement();
diff --git a/src/include/commands/cluster.h b/src/include/commands/cluster.h
index 77ef2b3bad..5af95a3d4e 100644
--- a/src/include/commands/cluster.h
+++ b/src/include/commands/cluster.h
@@ -24,6 +24,6 @@ extern void check_index_is_clusterable(Relation OldHeap, Oid indexOid,
extern void mark_index_clustered(Relation rel, Oid indexOid);
extern Oid make_new_heap(Oid OIDOldHeap, const char *NewName,
Oid NewTableSpace);
-extern void swap_relation_files(Oid r1, Oid r2);
+extern void swap_relation_files(Oid r1, Oid r2, TransactionId frozenXid);
#endif /* CLUSTER_H */