/*
* index_parallelscan_initialize - initialize parallel scan
*
* We initialize both the ParallelIndexScanDesc proper and the AM-specific
* information which follows it.
*
* This function calls access method specific initialization routine to
* initialize am specific information. Call this just once in the leader
* process; then, individual workers attach via index_beginscan_parallel.
*/
void
index_parallelscan_initialize(Relation heapRelation, Relation indexRelation,
Snapshot snapshot, ParallelIndexScanDesc target)
{
Size offset;
RELATION_CHECKS;
offset = add_size(offsetof(ParallelIndexScanDescData, ps_snapshot_data),
EstimateSnapshotSpace(snapshot));
offset = MAXALIGN(offset);
target->ps_relid = RelationGetRelid(heapRelation);
target->ps_indexid = RelationGetRelid(indexRelation);
target->ps_offset = offset;
SerializeSnapshot(snapshot, target->ps_snapshot_data);
/* aminitparallelscan is optional; assume no-op if not provided by AM */
if (indexRelation->rd_amroutine->aminitparallelscan != NULL)
{
void *amtarget;
amtarget = OffsetToPointer(target, offset);
indexRelation->rd_amroutine->aminitparallelscan(amtarget);
}
}
/* ----------------------------------------------------------------
* ExecBitmapHeapInitializeDSM
*
* Set up a parallel bitmap heap scan descriptor.
* ----------------------------------------------------------------
*/
void
ExecBitmapHeapInitializeDSM(BitmapHeapScanState *node,
ParallelContext *pcxt)
{
ParallelBitmapHeapState *pstate;
EState *estate = node->ss.ps.state;
dsa_area *dsa = node->ss.ps.state->es_query_dsa;
/* If there's no DSA, there are no workers; initialize nothing. */
if (dsa == NULL)
return;
pstate = shm_toc_allocate(pcxt->toc, node->pscan_len);
pstate->tbmiterator = 0;
pstate->prefetch_iterator = 0;
/* Initialize the mutex */
SpinLockInit(&pstate->mutex);
pstate->prefetch_pages = 0;
pstate->prefetch_target = 0;
pstate->state = BM_INITIAL;
ConditionVariableInit(&pstate->cv);
SerializeSnapshot(estate->es_snapshot, pstate->phs_snapshot_data);
shm_toc_insert(pcxt->toc, node->ss.ps.plan->plan_node_id, pstate);
node->pstate = pstate;
}
void
table_parallelscan_initialize(Relation rel, ParallelTableScanDesc pscan,
Snapshot snapshot)
{
Size snapshot_off = rel->rd_tableam->parallelscan_initialize(rel, pscan);
pscan->phs_snapshot_off = snapshot_off;
if (IsMVCCSnapshot(snapshot))
{
SerializeSnapshot(snapshot, (char *) pscan + pscan->phs_snapshot_off);
pscan->phs_snapshot_any = false;
}
else
{
Assert(snapshot == SnapshotAny);
pscan->phs_snapshot_any = true;
}
}
/* ----------------------------------------------------------------
* ExecBitmapHeapInitializeDSM
*
* Set up a parallel bitmap heap scan descriptor.
* ----------------------------------------------------------------
*/
void
ExecBitmapHeapInitializeDSM(BitmapHeapScanState *node,
ParallelContext *pcxt)
{
ParallelBitmapHeapState *pstate;
EState *estate = node->ss.ps.state;
pstate = shm_toc_allocate(pcxt->toc, node->pscan_len);
pstate->tbmiterator = 0;
pstate->prefetch_iterator = 0;
/* Initialize the mutex */
SpinLockInit(&pstate->mutex);
pstate->prefetch_pages = 0;
pstate->prefetch_target = 0;
pstate->state = BM_INITIAL;
ConditionVariableInit(&pstate->cv);
SerializeSnapshot(estate->es_snapshot, pstate->phs_snapshot_data);
shm_toc_insert(pcxt->toc, node->ss.ps.plan->plan_node_id, pstate);
node->pstate = pstate;
}