/* ----------------------------------------------------------------
 *		ExecInitGather
 * ----------------------------------------------------------------
 */
GatherMergeState *
ExecInitGatherMerge(GatherMerge *node, EState *estate, int eflags)
{
	GatherMergeState *gm_state;
	Plan	   *outerNode;
	TupleDesc	tupDesc;

	/* Gather merge node doesn't have innerPlan node. */
	Assert(innerPlan(node) == NULL);

	/*
	 * create state structure
	 */
	gm_state = makeNode(GatherMergeState);
	gm_state->ps.plan = (Plan *) node;
	gm_state->ps.state = estate;
	gm_state->ps.ExecProcNode = ExecGatherMerge;

	gm_state->initialized = false;
	gm_state->gm_initialized = false;
	gm_state->tuples_needed = -1;

	/*
	 * Miscellaneous initialization
	 *
	 * create expression context for node
	 */
	ExecAssignExprContext(estate, &gm_state->ps);

	/*
	 * GatherMerge doesn't support checking a qual (it's always more efficient
	 * to do it in the child node).
	 */
	Assert(!node->plan.qual);

	/*
	 * now initialize outer plan
	 */
	outerNode = outerPlan(node);
	outerPlanState(gm_state) = ExecInitNode(outerNode, estate, eflags);

	/*
	 * Leader may access ExecProcNode result directly (if
	 * need_to_scan_locally), or from workers via tuple queue.  So we can't
	 * trivially rely on the slot type being fixed for expressions evaluated
	 * within this node.
	 */
	gm_state->ps.outeropsset = true;
	gm_state->ps.outeropsfixed = false;

	/*
	 * Store the tuple descriptor into gather merge state, so we can use it
	 * while initializing the gather merge slots.
	 */
	tupDesc = ExecGetResultType(outerPlanState(gm_state));
	gm_state->tupDesc = tupDesc;

	/*
	 * Initialize result type and projection.
	 */
	ExecInitResultTypeTL(&gm_state->ps);
	ExecConditionalAssignProjectionInfo(&gm_state->ps, tupDesc, OUTER_VAR);

	/*
	 * Without projections result slot type is not trivially known, see
	 * comment above.
	 */
	if (gm_state->ps.ps_ProjInfo == NULL)
	{
		gm_state->ps.resultopsset = true;
		gm_state->ps.resultopsfixed = false;
	}

	/*
	 * initialize sort-key information
	 */
	if (node->numCols)
	{
		int			i;

		gm_state->gm_nkeys = node->numCols;
		gm_state->gm_sortkeys =
			palloc0(sizeof(SortSupportData) * node->numCols);

		for (i = 0; i < node->numCols; i++)
		{
			SortSupport sortKey = gm_state->gm_sortkeys + i;

			sortKey->ssup_cxt = CurrentMemoryContext;
			sortKey->ssup_collation = node->collations[i];
			sortKey->ssup_nulls_first = node->nullsFirst[i];
			sortKey->ssup_attno = node->sortColIdx[i];

			/*
			 * We don't perform abbreviated key conversion here, for the same
			 * reasons that it isn't used in MergeAppend
			 */
			sortKey->abbreviate = false;

			PrepareSortSupportFromOrderingOp(node->sortOperators[i], sortKey);
		}
	}

	/* Now allocate the workspace for gather merge */
	gather_merge_setup(gm_state);

	return gm_state;
}
示例#2
0
/* ----------------------------------------------------------------
 *		ExecInitGather
 * ----------------------------------------------------------------
 */
GatherMergeState *
ExecInitGatherMerge(GatherMerge *node, EState *estate, int eflags)
{
	GatherMergeState *gm_state;
	Plan	   *outerNode;
	bool		hasoid;
	TupleDesc	tupDesc;

	/* Gather merge node doesn't have innerPlan node. */
	Assert(innerPlan(node) == NULL);

	/*
	 * create state structure
	 */
	gm_state = makeNode(GatherMergeState);
	gm_state->ps.plan = (Plan *) node;
	gm_state->ps.state = estate;
	gm_state->ps.ExecProcNode = ExecGatherMerge;

	/*
	 * Miscellaneous initialization
	 *
	 * create expression context for node
	 */
	ExecAssignExprContext(estate, &gm_state->ps);

	/*
	 * initialize child expressions
	 */
	gm_state->ps.qual =
		ExecInitQual(node->plan.qual, &gm_state->ps);

	/*
	 * tuple table initialization
	 */
	ExecInitResultTupleSlot(estate, &gm_state->ps);

	/*
	 * now initialize outer plan
	 */
	outerNode = outerPlan(node);
	outerPlanState(gm_state) = ExecInitNode(outerNode, estate, eflags);

	/*
	 * Initialize result tuple type and projection info.
	 */
	ExecAssignResultTypeFromTL(&gm_state->ps);
	ExecAssignProjectionInfo(&gm_state->ps, NULL);

	gm_state->gm_initialized = false;

	/*
	 * initialize sort-key information
	 */
	if (node->numCols)
	{
		int			i;

		gm_state->gm_nkeys = node->numCols;
		gm_state->gm_sortkeys =
			palloc0(sizeof(SortSupportData) * node->numCols);

		for (i = 0; i < node->numCols; i++)
		{
			SortSupport sortKey = gm_state->gm_sortkeys + i;

			sortKey->ssup_cxt = CurrentMemoryContext;
			sortKey->ssup_collation = node->collations[i];
			sortKey->ssup_nulls_first = node->nullsFirst[i];
			sortKey->ssup_attno = node->sortColIdx[i];

			/*
			 * We don't perform abbreviated key conversion here, for the same
			 * reasons that it isn't used in MergeAppend
			 */
			sortKey->abbreviate = false;

			PrepareSortSupportFromOrderingOp(node->sortOperators[i], sortKey);
		}
	}

	/*
	 * store the tuple descriptor into gather merge state, so we can use it
	 * later while initializing the gather merge slots.
	 */
	if (!ExecContextForcesOids(&gm_state->ps, &hasoid))
		hasoid = false;
	tupDesc = ExecTypeFromTL(outerNode->targetlist, hasoid);
	gm_state->tupDesc = tupDesc;

	return gm_state;
}