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authorKevin Grittner <kgrittn@postgresql.org>2016-04-08 14:36:30 -0500
committerKevin Grittner <kgrittn@postgresql.org>2016-04-08 14:36:30 -0500
commit848ef42bb8c7909c9d7baa38178d4a209906e7c1 (patch)
treee15250d8dfd8f46b15e3ecfddfcad09799cc3866 /src/include/utils/rel.h
parent8b65cf4c5edabdcae45ceaef7b9ac236879aae50 (diff)
downloadpostgresql-848ef42bb8c7909c9d7baa38178d4a209906e7c1.tar.gz
Add the "snapshot too old" feature
This feature is controlled by a new old_snapshot_threshold GUC. A value of -1 disables the feature, and that is the default. The value of 0 is just intended for testing. Above that it is the number of minutes a snapshot can reach before pruning and vacuum are allowed to remove dead tuples which the snapshot would otherwise protect. The xmin associated with a transaction ID does still protect dead tuples. A connection which is using an "old" snapshot does not get an error unless it accesses a page modified recently enough that it might not be able to produce accurate results. This is similar to the Oracle feature, and we use the same SQLSTATE and error message for compatibility.
Diffstat (limited to 'src/include/utils/rel.h')
-rw-r--r--src/include/utils/rel.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/src/include/utils/rel.h b/src/include/utils/rel.h
index c7582c2a11..b5d82d6004 100644
--- a/src/include/utils/rel.h
+++ b/src/include/utils/rel.h
@@ -15,6 +15,7 @@
#define REL_H
#include "access/tupdesc.h"
+#include "access/xlog.h"
#include "catalog/pg_class.h"
#include "catalog/pg_index.h"
#include "fmgr.h"