diff --git a/contrib/auto_explain/auto_explain.c b/contrib/auto_explain/auto_explain.c
index cbbd25753f..b33b2211ca 100644
--- a/contrib/auto_explain/auto_explain.c
+++ b/contrib/auto_explain/auto_explain.c
@@ -26,7 +26,7 @@ static bool auto_explain_log_analyze = false;
static bool auto_explain_log_verbose = false;
static bool auto_explain_log_buffers = false;
static bool auto_explain_log_triggers = false;
-static bool auto_explain_log_timing = false;
+static bool auto_explain_log_timing = true;
static int auto_explain_log_format = EXPLAIN_FORMAT_TEXT;
static bool auto_explain_log_nested_statements = false;
@@ -200,8 +200,6 @@ explain_ExecutorStart(QueryDesc *queryDesc, int eflags)
queryDesc->instrument_options |= INSTRUMENT_TIMER;
else
queryDesc->instrument_options |= INSTRUMENT_ROWS;
-
-
if (auto_explain_log_buffers)
queryDesc->instrument_options |= INSTRUMENT_BUFFERS;
}
@@ -302,6 +300,7 @@ explain_ExecutorEnd(QueryDesc *queryDesc)
es.analyze = (queryDesc->instrument_options && auto_explain_log_analyze);
es.verbose = auto_explain_log_verbose;
es.buffers = (es.analyze && auto_explain_log_buffers);
+ es.timing = (es.analyze && auto_explain_log_timing);
es.format = auto_explain_log_format;
ExplainBeginOutput(&es);
diff --git a/doc/src/sgml/auto-explain.sgml b/doc/src/sgml/auto-explain.sgml
index 334996b0e6..d527208271 100644
--- a/doc/src/sgml/auto-explain.sgml
+++ b/doc/src/sgml/auto-explain.sgml
@@ -81,28 +81,13 @@ LOAD 'auto_explain';
When this parameter is on, per-plan-node timing occurs for all
statements executed, whether or not they run long enough to actually
get logged. This can have an extremely negative impact on performance.
+ Turning off auto_explain.log_timing ameliorates the
+ performance cost, at the price of obtaining less information.
-
-
- auto_explain.log_verbose (boolean)
-
- auto_explain.log_verbose configuration parameter
-
-
-
-
- auto_explain.log_verbose causes EXPLAIN VERBOSE
- output, rather than just EXPLAIN output, to be printed
- when an execution plan is logged. This parameter is off by default.
- Only superusers can change this setting.
-
-
-
-
auto_explain.log_buffers (boolean)
@@ -112,12 +97,37 @@ LOAD 'auto_explain';
- auto_explain.log_buffers causes EXPLAIN
- (ANALYZE, BUFFERS) output, rather than just EXPLAIN
- output, to be printed when an execution plan is logged. This parameter is
- off by default. Only superusers can change this setting. This
- parameter has no effect unless auto_explain.log_analyze
- parameter is set.
+ auto_explain.log_buffers controls whether buffer
+ usage statistics are printed when an execution plan is logged; it's
+ equivalent to the BUFFERS option of EXPLAIN.
+ This parameter has no effect
+ unless auto_explain.log_analyze is enabled.
+ This parameter is off by default.
+ Only superusers can change this setting.
+
+
+
+
+
+
+ auto_explain.log_timing (boolean)
+
+ auto_explain.log_timing configuration parameter
+
+
+
+
+ auto_explain.log_timing controls whether per-node
+ timing information is printed when an execution plan is logged; it's
+ equivalent to the TIMING option of EXPLAIN.
+ The overhead of repeatedly reading the system clock can slow down
+ queries significantly on some systems, so it may be useful to set this
+ parameter to off when only actual row counts, and not exact times, are
+ needed.
+ This parameter has no effect
+ unless auto_explain.log_analyze is enabled.
+ This parameter is on by default.
+ Only superusers can change this setting.
@@ -133,9 +143,28 @@ LOAD 'auto_explain';
auto_explain.log_triggers causes trigger
execution statistics to be included when an execution plan is logged.
- This parameter is off by default. Only superusers can change this
- setting. This parameter has no effect unless
- auto_explain.log_analyze parameter is set.
+ This parameter has no effect
+ unless auto_explain.log_analyze is enabled.
+ This parameter is off by default.
+ Only superusers can change this setting.
+
+
+
+
+
+
+ auto_explain.log_verbose (boolean)
+
+ auto_explain.log_verbose configuration parameter
+
+
+
+
+ auto_explain.log_verbose controls whether verbose
+ details are printed when an execution plan is logged; it's
+ equivalent to the VERBOSE option of EXPLAIN.
+ This parameter is off by default.
+ Only superusers can change this setting.
@@ -158,27 +187,6 @@ LOAD 'auto_explain';
-
-
- auto_explain.log_timing (boolean)
-
- auto_explain.log_timing configuration parameter
-
-
-
-
- auto_explain.log_timing causes EXPLAIN
- (ANALYZE, TIMING off) output, rather than just EXPLAIN (ANALYZE)
- output. The overhead of repeatedly reading the system clock can slow down the
- query significantly on some systems, so it may be useful to set this
- parameter to off when only actual row counts, and not exact times, are needed.
- This parameter is only effective when auto_explain.log_analyze
- is also enabled. This parameter is on by default.
- Only superusers can change this setting.
-
-
-
-
auto_explain.log_nested_statements (boolean)
@@ -198,7 +206,9 @@ LOAD 'auto_explain';
- These parameters must be set in postgresql.conf.
+ In ordinary usage, these parameters are set
+ in postgresql.conf, although superusers can alter them
+ on-the-fly within their own sessions.
Typical usage might be:
@@ -216,6 +226,7 @@ auto_explain.log_min_duration = '3s'
postgres=# LOAD 'auto_explain';
postgres=# SET auto_explain.log_min_duration = 0;
+postgres=# SET auto_explain.log_analyze = true;
postgres=# SELECT count(*)
FROM pg_class, pg_index
WHERE oid = indrelid AND indisunique;