diff options
author | Alvaro Herrera | 2008-07-11 02:10:14 +0000 |
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committer | Alvaro Herrera | 2008-07-11 02:10:14 +0000 |
commit | 75f191479258d294ba1e1b233cc3c32fbe79d4c5 (patch) | |
tree | e73ad3037ff43f606240725ff71029b19c833b09 | |
parent | 93947593b3fa5fa3b32fc1a494e1cc512a50bcef (diff) |
Make sure we only try to free snapshots that have been passed through
CopySnapshot, per Neil Conway. Also add a comment about the assumption in
GetSnapshotData that the argument is statically allocated.
Also, fix some more typos in comments in snapmgr.c.
-rw-r--r-- | src/backend/storage/ipc/procarray.c | 3 | ||||
-rw-r--r-- | src/backend/utils/time/snapmgr.c | 8 |
2 files changed, 7 insertions, 4 deletions
diff --git a/src/backend/storage/ipc/procarray.c b/src/backend/storage/ipc/procarray.c index 8603358ad9..d07ebcb36b 100644 --- a/src/backend/storage/ipc/procarray.c +++ b/src/backend/storage/ipc/procarray.c @@ -666,6 +666,9 @@ GetOldestXmin(bool allDbs, bool ignoreVacuum) * RecentGlobalXmin: the global xmin (oldest TransactionXmin across all * running transactions, except those running LAZY VACUUM). This is * the same computation done by GetOldestXmin(true, true). + * + * Note: this function should probably not be called with an argument that's + * not statically allocated (see xip allocation below). */ Snapshot GetSnapshotData(Snapshot snapshot) diff --git a/src/backend/utils/time/snapmgr.c b/src/backend/utils/time/snapmgr.c index 747e8c1e64..419c88a30d 100644 --- a/src/backend/utils/time/snapmgr.c +++ b/src/backend/utils/time/snapmgr.c @@ -3,10 +3,9 @@ * PostgreSQL snapshot manager * * We keep track of snapshots in two ways: the "registered snapshots" list, - * and the "active snapshot" stack. All snapshots in any of them is supposed - * to be in persistent memory. When a snapshot is no longer in any of these - * lists (tracked by separate refcounts of each snapshot), its memory can be - * freed. + * and the "active snapshot" stack. All snapshots in either of them live in + * persistent memory. When a snapshot is no longer in any of these lists + * (tracked by separate refcounts on each snapshot), its memory can be freed. * * These arrangements let us reset MyProc->xmin when there are no snapshots * referenced by this transaction. (One possible improvement would be to be @@ -261,6 +260,7 @@ FreeSnapshot(Snapshot snapshot) { Assert(snapshot->regd_count == 0); Assert(snapshot->active_count == 0); + Assert(snapshot->copied); pfree(snapshot); } |