Function RelationDecrementReferenceCount

src/backend/utils/cache/relcache.c:2240–6925

* RelationDecrementReferenceCount * Decrements relation reference count. */

 *		Decrements relation reference count.
 */
void
RelationDecrementReferenceCount(Relation rel)
{
	if (rel->rd_refcnt <= 0)
	{
		/*
		 * In CI intermittently ERROR is seen. To help debug the issue, just
		 * for debug builds elevating ERROR to PANIC.
		 */
#ifdef USE_ASSERT_CHECKING
		elog(PANIC,
#else
		elog(ERROR,
#endif
			 "Relation decrement reference count found relation %u/%u/%u with bad count (reference count %d)",
			 rel->rd_node.spcNode,
			 rel->rd_node.dbNode,
			 rel->rd_node.relNode,
			 rel->rd_refcnt);
	}
	
	rel->rd_refcnt -= 1;
	if (!IsBootstrapProcessingMode())
		ResourceOwnerForgetRelationRef(CurrentResourceOwner, rel);
}

/*
 * RelationClose - close an open relation
 *
 *	Actually, we just decrement the refcount.
 *
 *	NOTE: if compiled with -DRELCACHE_FORCE_RELEASE then relcache entries
 *	will be freed as soon as their refcount goes to zero.  In combination
 *	with aset.c's CLOBBER_FREED_MEMORY option, this provides a good test
 *	to catch references to already-released relcache entries.  It slows
 *	things down quite a bit, however.
 */
void
RelationClose(Relation relation)
{
	/* Note: no locking manipulations needed */
	RelationDecrementReferenceCount(relation);

	/*
	 * If the relation is no longer open in this session, we can clean up any
	 * stale partition descriptors it has.  This is unlikely, so check to see
	 * if there are child contexts before expending a call to mcxt.c.
	 */
	if (RelationHasReferenceCountZero(relation))
	{
		if (relation->rd_pdcxt != NULL &&
			relation->rd_pdcxt->firstchild != NULL)
			MemoryContextDeleteChildren(relation->rd_pdcxt);

		if (relation->rd_pddcxt != NULL &&
			relation->rd_pddcxt->firstchild != NULL)
			MemoryContextDeleteChildren(relation->rd_pddcxt);
	}