Function ExecSetupPartitionTupleRouting

src/backend/executor/execPartition.c:218–244

* ExecSetupPartitionTupleRouting - sets up information needed during * tuple routing for partitioned tables, encapsulates it in * PartitionTupleRouting, and returns it. * * Callers must use the returned PartitionTupleRouting during calls to * ExecFindPartition(). The actual ResultRelInfo for a partition is only * allocated when the partition is found for the first time. * * The current me

 * it should be estate->es_query_cxt.
 */
PartitionTupleRouting *
ExecSetupPartitionTupleRouting(EState *estate, Relation rel)
{
	PartitionTupleRouting *proute;

	/*
	 * Here we attempt to expend as little effort as possible in setting up
	 * the PartitionTupleRouting.  Each partition's ResultRelInfo is built on
	 * demand, only when we actually need to route a tuple to that partition.
	 * The reason for this is that a common case is for INSERT to insert a
	 * single tuple into a partitioned table and this must be fast.
	 */
	proute = (PartitionTupleRouting *) palloc0(sizeof(PartitionTupleRouting));
	proute->partition_root = rel;
	proute->memcxt = CurrentMemoryContext;
	/* Rest of members initialized by zeroing */

	/*
	 * Initialize this table's PartitionDispatch object.  Here we pass in the
	 * parent as NULL as we don't need to care about any parent of the target
	 * partitioned table.
	 */
	ExecInitPartitionDispatchInfo(estate, proute, RelationGetRelid(rel),
								  NULL, 0, NULL);

	return proute;
}

/*
 * ExecFindPartition -- Return the ResultRelInfo for the leaf partition that