diff options
Diffstat (limited to 'src/include/storage/predicate_internals.h')
| -rw-r--r-- | src/include/storage/predicate_internals.h | 21 |
1 files changed, 19 insertions, 2 deletions
diff --git a/src/include/storage/predicate_internals.h b/src/include/storage/predicate_internals.h index 0c90f275d65..fcbf2d8a220 100644 --- a/src/include/storage/predicate_internals.h +++ b/src/include/storage/predicate_internals.h @@ -57,9 +57,26 @@ typedef struct SERIALIZABLEXACT { VirtualTransactionId vxid; /* The executing process always has one of * these. */ + + /* + * We use two numbers to track the order that transactions commit. Before + * commit, a transaction is marked as prepared, and prepareSeqNo is set. + * Shortly after commit, it's marked as committed, and commitSeqNo is set. + * This doesn't give a strict commit order, but these two values together + * are good enough for us, as we can always err on the safe side and + * assume that there's a conflict, if we can't be sure of the exact + * ordering of two commits. + * + * Note that a transaction is marked as prepared for a short period during + * commit processing, even if two-phase commit is not used. But with + * two-phase commit, a transaction can stay in prepared state for some + * time. + */ + SerCommitSeqNo prepareSeqNo; SerCommitSeqNo commitSeqNo; - union /* these values are not both interesting at - * the same time */ + + /* these values are not both interesting at the same time */ + union { SerCommitSeqNo earliestOutConflictCommit; /* when committed with * conflict out */ |