* per-process shared memory data structures
*
*
- * Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1996-2012, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/include/storage/proc.h,v 1.120 2010/02/13 01:32:20 sriggs Exp $
+ * src/include/storage/proc.h
*
*-------------------------------------------------------------------------
*/
#ifndef _PROC_H_
#define _PROC_H_
+#include "access/xlog.h"
+#include "datatype/timestamp.h"
+#include "storage/latch.h"
#include "storage/lock.h"
#include "storage/pg_sema.h"
-#include "utils/timestamp.h"
/*
* Each backend advertises up to PGPROC_MAX_CACHED_SUBXIDS TransactionIds
struct XidCache
{
- bool overflowed;
- int nxids;
TransactionId xids[PGPROC_MAX_CACHED_SUBXIDS];
};
-/* Flags for PGPROC->vacuumFlags */
+/* Flags for PGXACT->vacuumFlags */
#define PROC_IS_AUTOVACUUM 0x01 /* is it an autovac worker? */
#define PROC_IN_VACUUM 0x02 /* currently running lazy vacuum */
#define PROC_IN_ANALYZE 0x04 /* currently running analyze */
/* flags reset at EOXact */
#define PROC_VACUUM_STATE_MASK (0x0E)
+/*
+ * We allow a small number of "weak" relation locks (AccesShareLock,
+ * RowShareLock, RowExclusiveLock) to be recorded in the PGPROC structure
+ * rather than the main lock table. This eases contention on the lock
+ * manager LWLocks. See storage/lmgr/README for additional details.
+ */
+#define FP_LOCK_SLOTS_PER_BACKEND 16
+
/*
* Each backend has a PGPROC struct in shared memory. There is also a list of
* currently-unused PGPROC structs that will be reallocated to new backends.
PGSemaphoreData sem; /* ONE semaphore to sleep on */
int waitStatus; /* STATUS_WAITING, STATUS_OK or STATUS_ERROR */
+ Latch procLatch; /* generic latch for process */
+
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,
/* Info about LWLock the process is currently waiting for, if any. */
bool lwWaiting; /* true if waiting for an LW lock */
- bool lwExclusive; /* true if waiting for exclusive access */
+ uint8 lwWaitMode; /* lwlock mode being waited for */
struct PGPROC *lwWaitLink; /* next waiter for same LW lock */
/* Info about lock the process is currently waiting for, if any. */
LOCKMASK heldLocks; /* bitmask for lock types already held on this
* lock object by this backend */
+ /*
+ * Info to allow us to wait for synchronous replication, if needed.
+ * waitLSN is InvalidXLogRecPtr if not waiting; set only by user backend.
+ * syncRepState must not be touched except by owning process or WALSender.
+ * syncRepLinks used only while holding SyncRepLock.
+ */
+ XLogRecPtr waitLSN; /* waiting for this LSN or higher */
+ int syncRepState; /* wait state for sync rep */
+ SHM_QUEUE syncRepLinks; /* list link if process is in syncrep queue */
+
/*
* All PROCLOCK objects for locks held or awaited by this backend are
* linked into one of these lists, according to the partition number of
SHM_QUEUE myProcLocks[NUM_LOCK_PARTITIONS];
struct XidCache subxids; /* cache for subtransaction XIDs */
+
+ /* Per-backend LWLock. Protects fields below. */
+ LWLockId backendLock; /* protects the fields below */
+
+ /* Lock manager data, recording fast-path locks taken by this backend. */
+ uint64 fpLockBits; /* lock modes held for each fast-path slot */
+ Oid fpRelId[FP_LOCK_SLOTS_PER_BACKEND]; /* slots for rel oids */
+ bool fpVXIDLock; /* are we holding a fast-path VXID lock? */
+ LocalTransactionId fpLocalTransactionId; /* lxid for fast-path VXID
+ * lock */
};
/* NOTE: "typedef struct PGPROC PGPROC" appears in storage/lock.h. */
extern PGDLLIMPORT PGPROC *MyProc;
+extern PGDLLIMPORT struct PGXACT *MyPgXact;
+/*
+ * Prior to PostgreSQL 9.2, the fields 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.
*/
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 */
PGPROC *freeProcs;
/* Head of list of autovacuum's free PGPROC structures */
PGPROC *autovacFreeProcs;
+ /* WALWriter process's latch */
+ Latch *walwriterLatch;
+ /* Checkpointer process's latch */
+ Latch *checkpointerLatch;
/* Current shared estimate of appropriate spins_per_delay value */
int spins_per_delay;
/* The proc of the Startup process, since not in ProcArray */
PGPROC *startupProc;
int startupProcPid;
- /* Buffer id of the buffer that Startup process waits for pin on */
+ /* Buffer id of the buffer that Startup process waits for pin on, or -1 */
int startupBufferPinWaitBufId;
} 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.
*
- * Background writer and WAL writer run during normal operation. Startup
- * process and WAL receiver also consume 2 slots, but WAL writer is
- * launched only after startup has exited, so we only need 3 slots.
+ * Background writer, checkpointer and WAL writer run during normal operation.
+ * Startup process and WAL receiver also consume 2 slots, but WAL writer is
+ * launched only after startup has exited, so we only need 4 slots.
*/
-#define NUM_AUXILIARY_PROCS 3
+#define NUM_AUXILIARY_PROCS 4
/* configurable options */
extern void PublishStartupProcessInformation(void);
extern void SetStartupBufferPinWaitBufId(int bufid);
-extern int GetStartupBufferPinWaitBufId(void);
+extern int GetStartupBufferPinWaitBufId(void);
extern bool HaveNFreeProcs(int n);
extern void ProcReleaseLocks(bool isCommit);
extern PGPROC *ProcWakeup(PGPROC *proc, int waitStatus);
extern void ProcLockWakeup(LockMethod lockMethodTable, LOCK *lock);
extern bool IsWaitingForLock(void);
-extern void LockWaitCancel(void);
+extern void LockErrorCleanup(void);
extern void ProcWaitForSignal(void);
extern void ProcSendSignal(int pid);
extern bool disable_sig_alarm(bool is_statement_timeout);
extern void handle_sig_alarm(SIGNAL_ARGS);
-extern bool enable_standby_sig_alarm(long delay_s, int delay_us, TimestampTz fin_time);
+extern bool enable_standby_sig_alarm(TimestampTz now,
+ TimestampTz fin_time, bool deadlock_only);
extern bool disable_standby_sig_alarm(void);
extern void handle_standby_sig_alarm(SIGNAL_ARGS);
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