diff options
Diffstat (limited to 'src/include/storage/lock.h')
| -rw-r--r-- | src/include/storage/lock.h | 17 |
1 files changed, 9 insertions, 8 deletions
diff --git a/src/include/storage/lock.h b/src/include/storage/lock.h index 2e6ef174e9a..68a3487d49f 100644 --- a/src/include/storage/lock.h +++ b/src/include/storage/lock.h @@ -46,10 +46,10 @@ extern bool Debug_deadlocks; /* * Top-level transactions are identified by VirtualTransactionIDs comprising - * the BackendId of the backend running the xact, plus a locally-assigned - * LocalTransactionId. These are guaranteed unique over the short term, - * but will be reused after a database restart; hence they should never - * be stored on disk. + * PGPROC fields backendId and lxid. For prepared transactions, the + * LocalTransactionId is an ordinary XID. These are guaranteed unique over + * the short term, but will be reused after a database restart or XID + * wraparound; hence they should never be stored on disk. * * Note that struct VirtualTransactionId can not be assumed to be atomically * assignable as a whole. However, type LocalTransactionId is assumed to @@ -61,15 +61,16 @@ extern bool Debug_deadlocks; */ typedef struct { - BackendId backendId; /* determined at backend startup */ - LocalTransactionId localTransactionId; /* backend-local transaction id */ + BackendId backendId; /* backendId from PGPROC */ + LocalTransactionId localTransactionId; /* lxid from PGPROC */ } VirtualTransactionId; #define InvalidLocalTransactionId 0 #define LocalTransactionIdIsValid(lxid) ((lxid) != InvalidLocalTransactionId) #define VirtualTransactionIdIsValid(vxid) \ - (((vxid).backendId != InvalidBackendId) && \ - LocalTransactionIdIsValid((vxid).localTransactionId)) + (LocalTransactionIdIsValid((vxid).localTransactionId)) +#define VirtualTransactionIdIsPreparedXact(vxid) \ + ((vxid).backendId == InvalidBackendId) #define VirtualTransactionIdEquals(vxid1, vxid2) \ ((vxid1).backendId == (vxid2).backendId && \ (vxid1).localTransactionId == (vxid2).localTransactionId) |