diff options
Diffstat (limited to 'src/include/storage/proc.h')
| -rw-r--r-- | src/include/storage/proc.h | 47 |
1 files changed, 31 insertions, 16 deletions
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h index 6e798b1b2d9..c7cddc79931 100644 --- a/src/include/storage/proc.h +++ b/src/include/storage/proc.h @@ -35,8 +35,6 @@ struct XidCache { - bool overflowed; - int nxids; TransactionId xids[PGPROC_MAX_CACHED_SUBXIDS]; }; @@ -86,27 +84,14 @@ struct PGPROC LocalTransactionId lxid; /* local id of top-level transaction currently * being executed by this proc, if running; * else InvalidLocalTransactionId */ - - TransactionId xid; /* id of top-level transaction currently being - * executed by this proc, if running and XID - * is assigned; else InvalidTransactionId */ - - TransactionId xmin; /* minimal running XID as it was when we were - * starting our xact, excluding LAZY VACUUM: - * vacuum must not remove tuples deleted by - * xid >= xmin ! */ - int pid; /* Backend's process ID; 0 if prepared xact */ + int pgprocno; /* These fields are zero while a backend is still starting up: */ BackendId backendId; /* This backend's backend ID (if assigned) */ Oid databaseId; /* OID of database this backend is using */ Oid roleId; /* OID of role using this backend */ - bool inCommit; /* true if within commit critical section */ - - uint8 vacuumFlags; /* vacuum-related flags, see above */ - /* * While in hot standby mode, shows that a conflict signal has been sent * for the current transaction. Set/cleared while holding ProcArrayLock, @@ -160,7 +145,33 @@ struct PGPROC extern PGDLLIMPORT PGPROC *MyProc; +extern PGDLLIMPORT struct PGXACT *MyPgXact; + +/* + * Prior to PostgreSQL 9.2, the fieds below were stored as part of the + * PGPROC. However, benchmarking revealed that packing these particular + * members into a separate array as tightly as possible sped up GetSnapshotData + * considerably on systems with many CPU cores, by reducing the number of + * cache lines needing to be fetched. Thus, think very carefully before adding + * anything else here. + */ +typedef struct PGXACT +{ + TransactionId xid; /* id of top-level transaction currently being + * executed by this proc, if running and XID + * is assigned; else InvalidTransactionId */ + + TransactionId xmin; /* minimal running XID as it was when we were + * starting our xact, excluding LAZY VACUUM: + * vacuum must not remove tuples deleted by + * xid >= xmin ! */ + + uint8 vacuumFlags; /* vacuum-related flags, see above */ + bool overflowed; + bool inCommit; /* true if within commit critical section */ + uint8 nxids; +} PGXACT; /* * There is one ProcGlobal struct for the whole database cluster. @@ -169,6 +180,8 @@ typedef struct PROC_HDR { /* Array of PGPROC structures (not including dummies for prepared txns) */ PGPROC *allProcs; + /* Array of PGXACT structures (not including dummies for prepared txns */ + PGXACT *allPgXact; /* Length of allProcs array */ uint32 allProcCount; /* Head of list of free PGPROC structures */ @@ -186,6 +199,8 @@ typedef struct PROC_HDR extern PROC_HDR *ProcGlobal; +extern PGPROC *PreparedXactProcs; + /* * We set aside some extra PGPROC structures for auxiliary processes, * ie things that aren't full-fledged backends but need shmem access. |