/*
* Initialize CommitTs at system startup (postmaster start or standalone
* backend)
*/
void
CommitTsShmemInit(void)
{
bool found;
CommitTsCtl->PagePrecedes = CommitTsPagePrecedes;
SimpleLruInit(CommitTsCtl, "commit_timestamp", CommitTsShmemBuffers(), 0,
CommitTsControlLock, "pg_commit_ts",
LWTRANCHE_COMMITTS_BUFFERS);
commitTsShared = ShmemInitStruct("CommitTs shared",
sizeof(CommitTimestampShared),
&found);
if (!IsUnderPostmaster)
{
Assert(!found);
commitTsShared->xidLastCommit = InvalidTransactionId;
TIMESTAMP_NOBEGIN(commitTsShared->dataLastCommit.time);
commitTsShared->dataLastCommit.nodeid = InvalidRepOriginId;
commitTsShared->commitTsActive = false;
}
else
Assert(found);
}
/*
* Compute number of LWLocks to allocate in the main array.
*/
static int
NumLWLocks(void)
{
int numLocks;
/*
* Possibly this logic should be spread out among the affected modules,
* the same way that shmem space estimation is done. But for now, there
* are few enough users of LWLocks that we can get away with just keeping
* the knowledge here.
*/
/* Predefined LWLocks */
numLocks = NUM_FIXED_LWLOCKS;
/* bufmgr.c needs two for each shared buffer */
numLocks += 2 * NBuffers;
/* proc.c needs one for each backend or auxiliary process */
numLocks += MaxBackends + NUM_AUXILIARY_PROCS;
/* clog.c needs one per CLOG buffer */
numLocks += CLOGShmemBuffers();
/* commit_ts.c needs one per CommitTs buffer */
numLocks += CommitTsShmemBuffers();
/* subtrans.c needs one per SubTrans buffer */
numLocks += NUM_SUBTRANS_BUFFERS;
/* multixact.c needs two SLRU areas */
numLocks += NUM_MXACTOFFSET_BUFFERS + NUM_MXACTMEMBER_BUFFERS;
/* async.c needs one per Async buffer */
numLocks += NUM_ASYNC_BUFFERS;
/* predicate.c needs one per old serializable xid buffer */
numLocks += NUM_OLDSERXID_BUFFERS;
/* slot.c needs one for each slot */
numLocks += max_replication_slots;
/*
* Add any requested by loadable modules; for backwards-compatibility
* reasons, allocate at least NUM_USER_DEFINED_LWLOCKS of them even if
* there are no explicit requests.
*/
lock_addin_request_allowed = false;
numLocks += Max(lock_addin_request, NUM_USER_DEFINED_LWLOCKS);
return numLocks;
}
/*
* Shared memory sizing for CommitTs
*/
Size
CommitTsShmemSize(void)
{
return SimpleLruShmemSize(CommitTsShmemBuffers(), 0) +
sizeof(CommitTimestampShared);
}
