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ca7578d454
should be accounted for in the PROC_SEM_MAP_ENTRIES() macro. Otherwise the ports that rely on this macro to size data structures are broken. Mea culpa.
158 lines
5 KiB
C
158 lines
5 KiB
C
/*-------------------------------------------------------------------------
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*
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* proc.h
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* per-process shared memory data structures
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*
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*
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* Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* $Id: proc.h,v 1.54 2001/11/06 00:38:26 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef _PROC_H_
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#define _PROC_H_
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#include "access/xlog.h"
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#include "storage/backendid.h"
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#include "storage/ipc.h"
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#include "storage/lock.h"
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typedef struct
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{
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IpcSemaphoreId semId; /* SysV semaphore set ID */
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int semNum; /* semaphore number within set */
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} SEMA;
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/*
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* Each backend has a PROC struct in shared memory. There is also a list of
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* currently-unused PROC structs that will be reallocated to new backends.
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*
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* links: list link for any list the PROC is in. When waiting for a lock,
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* the PROC is linked into that lock's waitProcs queue. A recycled PROC
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* is linked into ProcGlobal's freeProcs list.
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*/
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struct PROC
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{
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/* proc->links MUST BE FIRST IN STRUCT (see ProcSleep,ProcWakeup,etc) */
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SHM_QUEUE links; /* list link if process is in a list */
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SEMA sem; /* ONE semaphore to sleep on */
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int errType; /* STATUS_OK or STATUS_ERROR after wakeup */
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TransactionId xid; /* transaction currently being executed by
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* this proc */
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TransactionId xmin; /* minimal running XID as it was when we
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* were starting our xact: vacuum must not
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* remove tuples deleted by xid >= xmin ! */
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int pid; /* This backend's process id */
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Oid databaseId; /* OID of database this backend is using */
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/*
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* XLOG location of first XLOG record written by this backend's
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* current transaction. If backend is not in a transaction or hasn't
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* yet modified anything, logRec.xrecoff is zero.
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*/
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XLogRecPtr logRec;
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/* Info about LWLock the process is currently waiting for, if any. */
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bool lwWaiting; /* true if waiting for an LW lock */
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bool lwExclusive; /* true if waiting for exclusive access */
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struct PROC *lwWaitLink; /* next waiter for same LW lock */
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/* Info about lock the process is currently waiting for, if any. */
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/* waitLock and waitHolder are NULL if not currently waiting. */
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LOCK *waitLock; /* Lock object we're sleeping on ... */
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HOLDER *waitHolder; /* Per-holder info for awaited lock */
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LOCKMODE waitLockMode; /* type of lock we're waiting for */
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LOCKMASK heldLocks; /* bitmask for lock types already held on
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* this lock object by this backend */
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SHM_QUEUE procHolders; /* list of HOLDER objects for locks held
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* or awaited by this backend */
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};
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/* NOTE: "typedef struct PROC PROC" appears in storage/lock.h. */
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extern PROC *MyProc;
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/*
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* There is one ProcGlobal struct for the whole installation.
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*
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* PROC_NSEMS_PER_SET is the number of semaphores in each sys-V semaphore set
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* we allocate. It must be no more than 32 (or however many bits in an int
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* on your machine), or our free-semaphores bitmap won't work. It also must
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* be *less than* your kernel's SEMMSL (max semaphores per set) parameter,
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* which is often around 25. (Less than, because we allocate one extra sema
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* in each set for identification purposes.)
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*
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* PROC_SEM_MAP_ENTRIES is the number of semaphore sets we need to allocate
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* to keep track of up to maxBackends backends. Note that we need one extra
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* semaphore (see storage/lmgr/proc.c), so the computation may look wrong,
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* but it's right.
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*/
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#define PROC_NSEMS_PER_SET 16
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#define PROC_SEM_MAP_ENTRIES(maxBackends) ((maxBackends)/PROC_NSEMS_PER_SET+1)
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typedef struct
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{
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/* info about a single set of per-process semaphores */
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IpcSemaphoreId procSemId;
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int32 freeSemMap;
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/*
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* In freeSemMap, bit i is set if the i'th semaphore of this sema set
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* is allocated to a process. (i counts from 0 at the LSB)
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*/
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} SEM_MAP_ENTRY;
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typedef struct PROC_HDR
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{
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/* Head of list of free PROC structures */
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SHMEM_OFFSET freeProcs;
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/* Info about semaphore sets used for per-process semaphores */
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int semMapEntries;
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/*
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* VARIABLE LENGTH ARRAY: actual length is semMapEntries. THIS MUST BE
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* LAST IN THE STRUCT DECLARATION.
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*/
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SEM_MAP_ENTRY procSemMap[1];
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} PROC_HDR;
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/* configurable option */
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extern int DeadlockTimeout;
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/*
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* Function Prototypes
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*/
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extern void InitProcGlobal(int maxBackends);
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extern void InitProcess(void);
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extern void InitDummyProcess(void);
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extern void ProcReleaseLocks(bool isCommit);
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extern void ProcQueueInit(PROC_QUEUE *queue);
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extern int ProcSleep(LOCKMETHODTABLE *lockMethodTable, LOCKMODE lockmode,
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LOCK *lock, HOLDER *holder);
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extern PROC *ProcWakeup(PROC *proc, int errType);
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extern void ProcLockWakeup(LOCKMETHODTABLE *lockMethodTable, LOCK *lock);
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extern bool LockWaitCancel(void);
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extern void HandleDeadLock(SIGNAL_ARGS);
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extern void ProcWaitForSignal(void);
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extern void ProcCancelWaitForSignal(void);
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extern void ProcSendSignal(BackendId procId);
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extern bool enable_sigalrm_interrupt(int delayms);
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extern bool disable_sigalrm_interrupt(void);
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#endif /* PROC_H */
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