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| author | Thomas Munro <tmunro@postgresql.org> | 2019-03-27 21:16:50 +1300 |
|---|---|---|
| committer | Thomas Munro <tmunro@postgresql.org> | 2019-03-27 21:30:04 +1300 |
| commit | d2fd7f74ee61f41a3bd5daf2942b72cebd88f346 (patch) | |
| tree | 931fb937a69857d64191d6a4fa34d878f69c2aab /src | |
| parent | 1983af8e899389187026cb34c1ca9d89ea986120 (diff) | |
| download | postgresql-d2fd7f74ee61f41a3bd5daf2942b72cebd88f346.tar.gz postgresql-d2fd7f74ee61f41a3bd5daf2942b72cebd88f346.zip | |
Fix off-by-one error in txid_status().
The transaction ID returned by GetNextXidAndEpoch() is in the future,
so we can't attempt to access its status or we might try to read a
CLOG page that doesn't exist. The > vs >= confusion probably stemmed
from the choice of a variable name containing the word "last" instead
of "next", so fix that too.
Back-patch to 10 where the function arrived.
Author: Thomas Munro
Discussion: https://postgr.es/m/CA%2BhUKG%2Buua_BV5cyfsioKVN2d61Lukg28ECsWTXKvh%3DBtN2DPA%40mail.gmail.com
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/utils/adt/txid.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/src/backend/utils/adt/txid.c b/src/backend/utils/adt/txid.c index 791bbf84024..9958b1a55e8 100644 --- a/src/backend/utils/adt/txid.c +++ b/src/backend/utils/adt/txid.c @@ -113,9 +113,9 @@ TransactionIdInRecentPast(uint64 xid_with_epoch, TransactionId *extracted_xid) uint32 xid_epoch = (uint32) (xid_with_epoch >> 32); TransactionId xid = (TransactionId) xid_with_epoch; uint32 now_epoch; - TransactionId now_epoch_last_xid; + TransactionId now_epoch_next_xid; - GetNextXidAndEpoch(&now_epoch_last_xid, &now_epoch); + GetNextXidAndEpoch(&now_epoch_next_xid, &now_epoch); if (extracted_xid != NULL) *extracted_xid = xid; @@ -129,7 +129,7 @@ TransactionIdInRecentPast(uint64 xid_with_epoch, TransactionId *extracted_xid) /* If the transaction ID is in the future, throw an error. */ if (xid_epoch > now_epoch - || (xid_epoch == now_epoch && xid > now_epoch_last_xid)) + || (xid_epoch == now_epoch && xid >= now_epoch_next_xid)) ereport(ERROR, (errcode(ERRCODE_INVALID_PARAMETER_VALUE), errmsg("transaction ID %s is in the future", @@ -151,7 +151,7 @@ TransactionIdInRecentPast(uint64 xid_with_epoch, TransactionId *extracted_xid) * CLOG entry is guaranteed to still exist. */ if (xid_epoch + 1 < now_epoch - || (xid_epoch + 1 == now_epoch && xid < now_epoch_last_xid) + || (xid_epoch + 1 == now_epoch && xid < now_epoch_next_xid) || TransactionIdPrecedes(xid, ShmemVariableCache->oldestClogXid)) return false; |