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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2011-10-22 18:22:45 -0400 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2011-10-22 18:23:30 -0400 |
| commit | bb446b689b6681eb57a8a50605e119743190c4db (patch) | |
| tree | 2605250c0d2a465c4ff6ef7454df4c56902759cd /src/backend/access/transam/xlog.c | |
| parent | b436c72f61adf5efab435c282bfb13a29508d475 (diff) | |
| download | postgresql-bb446b689b6681eb57a8a50605e119743190c4db.tar.gz postgresql-bb446b689b6681eb57a8a50605e119743190c4db.zip | |
Support synchronization of snapshots through an export/import procedure.
A transaction can export a snapshot with pg_export_snapshot(), and then
others can import it with SET TRANSACTION SNAPSHOT. The data does not
leave the server so there are not security issues. A snapshot can only
be imported while the exporting transaction is still running, and there
are some other restrictions.
I'm not totally convinced that we've covered all the bases for SSI (true
serializable) mode, but it works fine for lesser isolation modes.
Joachim Wieland, reviewed by Marko Tiikkaja, and rather heavily modified
by Tom Lane
Diffstat (limited to 'src/backend/access/transam/xlog.c')
| -rw-r--r-- | src/backend/access/transam/xlog.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 1c17348472e..5fec88691a3 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -58,6 +58,7 @@ #include "utils/guc.h" #include "utils/ps_status.h" #include "utils/relmapper.h" +#include "utils/snapmgr.h" #include "utils/timestamp.h" #include "pg_trace.h" @@ -6382,6 +6383,12 @@ StartupXLOG(void) ResetUnloggedRelations(UNLOGGED_RELATION_CLEANUP); /* + * Likewise, delete any saved transaction snapshot files that got + * left behind by crashed backends. + */ + DeleteAllExportedSnapshotFiles(); + + /* * Initialize for Hot Standby, if enabled. We won't let backends in * yet, not until we've reached the min recovery point specified in * control file and we've established a recovery snapshot from a |