From 1f0c6a9e7dca70ba7d2c949e42298d764ca457c0 Mon Sep 17 00:00:00 2001
From: Andres Freund <andres@anarazel.de>
Date: Wed, 28 Mar 2018 13:26:51 -0700
Subject: [PATCH] Add EXPLAIN support for JIT.

This just shows a few details about JITing, e.g. how many functions
have been JITed, and how long that took.  To avoid noise in regression
tests with functions sometimes being JITed in --with-llvm builds,
disable display when COSTS OFF is specified.

Author: Andres Freund
Discussion: https://postgr.es/m/20170901064131.tazjxwus3k2w3ybh@alap3.anarazel.de
---
 src/backend/commands/explain.c | 59 ++++++++++++++++++++++++++++++++++
 src/include/commands/explain.h |  2 ++
 2 files changed, 61 insertions(+)

diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index c38d178cd9..8a58672a94 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -21,6 +21,7 @@
 #include "commands/prepare.h"
 #include "executor/nodeHash.h"
 #include "foreign/fdwapi.h"
+#include "jit/jit.h"
 #include "nodes/extensible.h"
 #include "nodes/nodeFuncs.h"
 #include "optimizer/clauses.h"
@@ -556,6 +557,16 @@ ExplainOnePlan(PlannedStmt *plannedstmt, IntoClause *into, ExplainState *es,
 	if (es->analyze)
 		ExplainPrintTriggers(es, queryDesc);
 
+	/*
+	 * Print info about JITing. Tied to es->costs because we don't want to
+	 * display this in regression tests, as it'd cause output differences
+	 * depending on build options.  Might want to separate that out from COSTS
+	 * at a later stage.
+	 */
+	if (queryDesc->estate->es_jit && es->costs &&
+		queryDesc->estate->es_jit->created_functions > 0)
+		ExplainPrintJIT(es, queryDesc);
+
 	/*
 	 * Close down the query and free resources.  Include time for this in the
 	 * total execution time (although it should be pretty minimal).
@@ -677,6 +688,54 @@ ExplainPrintTriggers(ExplainState *es, QueryDesc *queryDesc)
 	ExplainCloseGroup("Triggers", "Triggers", false, es);
 }
 
+/*
+ * ExplainPrintJIT -
+ *	  Append information about JITing to es->str.
+ */
+void
+ExplainPrintJIT(ExplainState *es, QueryDesc *queryDesc)
+{
+	JitContext *jc = queryDesc->estate->es_jit;
+
+	ExplainOpenGroup("JIT", "JIT", true, es);
+
+	if (es->format == EXPLAIN_FORMAT_TEXT)
+	{
+		es->indent += 1;
+		appendStringInfo(es->str, "JIT:\n");
+	}
+
+	ExplainPropertyInteger("Functions", NULL, jc->created_functions, es);
+	if (es->analyze && es->timing)
+		ExplainPropertyFloat("Generation Time", "ms",
+							 1000.0 * INSTR_TIME_GET_DOUBLE(jc->generation_counter),
+							 3, es);
+
+	ExplainPropertyBool("Inlining", jc->flags & PGJIT_INLINE, es);
+
+	if (es->analyze && es->timing)
+		ExplainPropertyFloat("Inlining Time", "ms",
+							 1000.0 * INSTR_TIME_GET_DOUBLE(jc->inlining_counter),
+							 3, es);
+
+	ExplainPropertyBool("Optimization", jc->flags & PGJIT_OPT3, es);
+	if (es->analyze && es->timing)
+		ExplainPropertyFloat("Optimization Time", "ms",
+							 1000.0 * INSTR_TIME_GET_DOUBLE(jc->optimization_counter),
+							 3, es);
+
+	if (es->analyze && es->timing)
+		ExplainPropertyFloat("Emission Time", "ms",
+							 1000.0 * INSTR_TIME_GET_DOUBLE(jc->emission_counter),
+							 3, es);
+
+	ExplainCloseGroup("JIT", "JIT", true, es);
+	if (es->format == EXPLAIN_FORMAT_TEXT)
+	{
+		es->indent -= 1;
+	}
+}
+
 /*
  * ExplainQueryText -
  *	  add a "Query Text" node that contains the actual text of the query
diff --git a/src/include/commands/explain.h b/src/include/commands/explain.h
index 6d3d94cae2..9b75baae6e 100644
--- a/src/include/commands/explain.h
+++ b/src/include/commands/explain.h
@@ -81,6 +81,8 @@ extern void ExplainOnePlan(PlannedStmt *plannedstmt, IntoClause *into,
 extern void ExplainPrintPlan(ExplainState *es, QueryDesc *queryDesc);
 extern void ExplainPrintTriggers(ExplainState *es, QueryDesc *queryDesc);
 
+extern void ExplainPrintJIT(ExplainState *es, QueryDesc *queryDesc);
+
 extern void ExplainQueryText(ExplainState *es, QueryDesc *queryDesc);
 
 extern void ExplainBeginOutput(ExplainState *es);
-- 
2.40.0