autho_explain: Add GUC to log query parameters

auto_explain.log_parameter_max_length is a new GUC part of the
extension, similar to the corresponding core setting, that controls the
inclusion of query parameters in the logged explain output.

More tests are added to check the behavior of this new parameter: when
parameters logged in full (the default of -1), when disabled (value of
0) and when partially truncated (value different than the two others).

Author: Dagfinn Ilmari Mannsåker
Discussion: https://postgr.es/m/[email protected]

1 files changed, 15 insertions, 0 deletions

diff --git a/contrib/auto_explain/auto_explain.c b/contrib/auto_explain/auto_explain.c
index c9a0d947c83..1ba7536879d 100644
--- a/contrib/auto_explain/auto_explain.c
+++ b/contrib/auto_explain/auto_explain.c
@@ -19,12 +19,14 @@
 #include "common/pg_prng.h"
 #include "executor/instrument.h"
 #include "jit/jit.h"
+#include "nodes/params.h"
 #include "utils/guc.h"
 
 PG_MODULE_MAGIC;
 
 /* GUC variables */
 static int	auto_explain_log_min_duration = -1; /* msec or -1 */
+static int	auto_explain_log_parameter_max_length = -1; /* bytes or -1 */
 static bool auto_explain_log_analyze = false;
 static bool auto_explain_log_verbose = false;
 static bool auto_explain_log_buffers = false;
@@ -105,6 +107,18 @@ _PG_init(void)
 							NULL,
 							NULL);
 
+	DefineCustomIntVariable("auto_explain.log_parameter_max_length",
+							"Sets the maximum length of query parameters to log.",
+							"Zero logs no query parameters, -1 logs them in full.",
+							&auto_explain_log_parameter_max_length,
+							-1,
+							-1, INT_MAX,
+							PGC_SUSET,
+							GUC_UNIT_BYTE,
+							NULL,
+							NULL,
+							NULL);
+
 	DefineCustomBoolVariable("auto_explain.log_analyze",
 							 "Use EXPLAIN ANALYZE for plan logging.",
 							 NULL,
@@ -389,6 +403,7 @@ explain_ExecutorEnd(QueryDesc *queryDesc)
 
 			ExplainBeginOutput(es);
 			ExplainQueryText(es, queryDesc);
+			ExplainQueryParameters(es, queryDesc->params, auto_explain_log_parameter_max_length);
 			ExplainPrintPlan(es, queryDesc);
 			if (es->analyze && auto_explain_log_triggers)
 				ExplainPrintTriggers(es, queryDesc);