1 files changed, 144 insertions, 0 deletions

diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index 872aaa7aedc..ede8cec9472 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -108,6 +108,8 @@ static void show_sort_info(SortState *sortstate, ExplainState *es);
 static void show_incremental_sort_info(IncrementalSortState *incrsortstate,
 									   ExplainState *es);
 static void show_hash_info(HashState *hashstate, ExplainState *es);
+static void show_resultcache_info(ResultCacheState *rcstate, List *ancestors,
+								  ExplainState *es);
 static void show_hashagg_info(AggState *hashstate, ExplainState *es);
 static void show_tidbitmap_info(BitmapHeapScanState *planstate,
 								ExplainState *es);
@@ -1284,6 +1286,9 @@ ExplainNode(PlanState *planstate, List *ancestors,
 		case T_Material:
 			pname = sname = "Materialize";
 			break;
+		case T_ResultCache:
+			pname = sname = "Result Cache";
+			break;
 		case T_Sort:
 			pname = sname = "Sort";
 			break;
@@ -1996,6 +2001,10 @@ ExplainNode(PlanState *planstate, List *ancestors,
 		case T_Hash:
 			show_hash_info(castNode(HashState, planstate), es);
 			break;
+		case T_ResultCache:
+			show_resultcache_info(castNode(ResultCacheState, planstate),
+								  ancestors, es);
+			break;
 		default:
 			break;
 	}
@@ -3064,6 +3073,141 @@ show_hash_info(HashState *hashstate, ExplainState *es)
 }
 
 /*
+ * Show information on result cache hits/misses/evictions and memory usage.
+ */
+static void
+show_resultcache_info(ResultCacheState *rcstate, List *ancestors,
+					  ExplainState *es)
+{
+	Plan	   *plan = ((PlanState *) rcstate)->plan;
+	ListCell   *lc;
+	List	   *context;
+	StringInfoData keystr;
+	char	   *seperator = "";
+	bool		useprefix;
+	int64		memPeakKb;
+
+	initStringInfo(&keystr);
+
+	/*
+	 * It's hard to imagine having a result cache with fewer than 2 RTEs, but
+	 * let's just keep the same useprefix logic as elsewhere in this file.
+	 */
+	useprefix = list_length(es->rtable) > 1 || es->verbose;
+
+	/* Set up deparsing context */
+	context = set_deparse_context_plan(es->deparse_cxt,
+									   plan,
+									   ancestors);
+
+	foreach(lc, ((ResultCache *) plan)->param_exprs)
+	{
+		Node	   *expr = (Node *) lfirst(lc);
+
+		appendStringInfoString(&keystr, seperator);
+
+		appendStringInfoString(&keystr, deparse_expression(expr, context,
+														   useprefix, false));
+		seperator = ", ";
+	}
+
+	if (es->format != EXPLAIN_FORMAT_TEXT)
+	{
+		ExplainPropertyText("Cache Key", keystr.data, es);
+	}
+	else
+	{
+		ExplainIndentText(es);
+		appendStringInfo(es->str, "Cache Key: %s\n", keystr.data);
+	}
+
+	pfree(keystr.data);
+
+	if (!es->analyze)
+		return;
+
+	/*
+	 * mem_peak is only set when we freed memory, so we must use mem_used when
+	 * mem_peak is 0.
+	 */
+	if (rcstate->stats.mem_peak > 0)
+		memPeakKb = (rcstate->stats.mem_peak + 1023) / 1024;
+	else
+		memPeakKb = (rcstate->mem_used + 1023) / 1024;
+
+	if (rcstate->stats.cache_misses > 0)
+	{
+		if (es->format != EXPLAIN_FORMAT_TEXT)
+		{
+			ExplainPropertyInteger("Cache Hits", NULL, rcstate->stats.cache_hits, es);
+			ExplainPropertyInteger("Cache Misses", NULL, rcstate->stats.cache_misses, es);
+			ExplainPropertyInteger("Cache Evictions", NULL, rcstate->stats.cache_evictions, es);
+			ExplainPropertyInteger("Cache Overflows", NULL, rcstate->stats.cache_overflows, es);
+			ExplainPropertyInteger("Peak Memory Usage", "kB", memPeakKb, es);
+		}
+		else
+		{
+			ExplainIndentText(es);
+			appendStringInfo(es->str,
+							 "Hits: " UINT64_FORMAT "  Misses: " UINT64_FORMAT "  Evictions: " UINT64_FORMAT "  Overflows: " UINT64_FORMAT "  Memory Usage: " INT64_FORMAT "kB\n",
+							 rcstate->stats.cache_hits,
+							 rcstate->stats.cache_misses,
+							 rcstate->stats.cache_evictions,
+							 rcstate->stats.cache_overflows,
+							 memPeakKb);
+		}
+	}
+
+	if (rcstate->shared_info == NULL)
+		return;
+
+	/* Show details from parallel workers */
+	for (int n = 0; n < rcstate->shared_info->num_workers; n++)
+	{
+		ResultCacheInstrumentation *si;
+
+		si = &rcstate->shared_info->sinstrument[n];
+
+		if (es->workers_state)
+			ExplainOpenWorker(n, es);
+
+		/*
+		 * Since the worker's ResultCacheState.mem_used field is unavailable
+		 * to us, ExecEndResultCache will have set the
+		 * ResultCacheInstrumentation.mem_peak field for us.  No need to do
+		 * the zero checks like we did for the serial case above.
+		 */
+		memPeakKb = (si->mem_peak + 1023) / 1024;
+
+		if (es->format == EXPLAIN_FORMAT_TEXT)
+		{
+			ExplainIndentText(es);
+			appendStringInfo(es->str,
+							 "Hits: " UINT64_FORMAT "  Misses: " UINT64_FORMAT "  Evictions: " UINT64_FORMAT "  Overflows: " UINT64_FORMAT "  Memory Usage: " INT64_FORMAT "kB\n",
+							 si->cache_hits, si->cache_misses,
+							 si->cache_evictions, si->cache_overflows,
+							 memPeakKb);
+		}
+		else
+		{
+			ExplainPropertyInteger("Cache Hits", NULL,
+								   si->cache_hits, es);
+			ExplainPropertyInteger("Cache Misses", NULL,
+								   si->cache_misses, es);
+			ExplainPropertyInteger("Cache Evictions", NULL,
+								   si->cache_evictions, es);
+			ExplainPropertyInteger("Cache Overflows", NULL,
+								   si->cache_overflows, es);
+			ExplainPropertyInteger("Peak Memory Usage", "kB", memPeakKb,
+								   es);
+		}
+
+		if (es->workers_state)
+			ExplainCloseWorker(n, es);
+	}
+}
+
+/*
  * Show information on hash aggregate memory usage and batches.
  */
 static void