On 2022-09-19 17:47, Алена Рыбакина wrote:
Thanks for your review and comments!
Hi,
I'm sorry,if this message is duplicated previous this one, but I'm not
sure that the previous message is sent correctly. I sent it from email
address a.rybak...@postgrespro.ru and I couldn't send this one email
from those address.
I've successfully received your mail from both a.rybak...@postgrespro.ru
and lena.riback...@yandex.ru.
I like idea to create patch for logging query plan. After reviewing
this code and notice some moments and I'd rather ask you some
questions.
Firstly, I suggest some editing in the comment of commit. I think, it
is
turned out the more laconic and the same clear. I wrote it below since
I
can't think of any other way to add it.
```
Currently, we have to wait for finishing of the query execution to
check
its plan.
This is not so convenient in investigation long-running queries on
production
environments where we cannot use debuggers.
To improve this situation there is proposed the patch containing the
pg_log_query_plan()
function which request to log plan of the specified backend process.
By default, only superusers are allowed to request log of the plan
otherwise
allowing any users to issue this request could create cause lots of log
messages
and it can lead to denial of service.
At the next requesting CHECK_FOR_INTERRUPTS(), the target backend logs
its plan at
LOG_SERVER_ONLY level and therefore this plan will appear in the server
log only,
not to be sent to the client.
Thanks, I have incorporated your comments.
Since the latter part of the original message comes from the commit
message of pg_log_backend_memory_contexts(43620e328617c), so I left it
as it was for consistency.
Secondly, I have question about deleting USE_ASSERT_CHECKING in lock.h?
It supposed to have been checked in another placed of the code by
matching values. I am worry about skipping errors due to untesting with
assert option in the places where it (GetLockMethodLocalHash)
participates and we won't able to get core file in segfault cases. I
might not understand something, then can you please explain to me?
Since GetLockMethodLocalHash() is only used for assertions, this is only
defined when USE_ASSERT_CHECKING is enabled.
This patch uses GetLockMethodLocalHash() not only for the assertion
purpose, so I removed "ifdef USE_ASSERT_CHECKING" for this function.
I belive it does not lead to skip errors.
Thirdly, I have incomprehension of the point why save_ActiveQueryDesc
is
declared in the pquery.h? I am seemed to save_ActiveQueryDesc to be
used
in an once time in the ExecutorRun function and its declaration
superfluous. I added it in the attached patch.
Exactly.
Fourthly, it seems to me there are not enough explanatory comments in
the code. I also added them in the attached patch.
Thanks!
| + /*
| + * Save value of ActiveQueryDesc before having called
| + * ExecutorRun_hook function due to having reset by
| + * AbortSubTransaction.
| + */
| +
| save_ActiveQueryDesc = ActiveQueryDesc;
| ActiveQueryDesc = queryDesc;
|
| @@ -314,6 +320,7 @@ ExecutorRun(QueryDesc *queryDesc,
| else
| standard_ExecutorRun(queryDesc, direction, count,
execute_once);
|
| + /* We set the actual value of ActiveQueryDesc */
| ActiveQueryDesc = save_ActiveQueryDesc;
Since these processes are needed for nested queries, not only for
AbortSubTransaction[1], added comments on it.
| +/* Function to handle the signal to output the query plan. */
| extern void HandleLogQueryPlanInterrupt(void);
I feel this comment is unnecessary since the explanation of
HandleLogQueryPlanInterrupt() is written in explain.c and no functions
in explain.h have comments in it.
Lastly, I have incomprehension about handling signals since have been
unused it before. Could another signal disabled calling this signal to
log query plan? I noticed this signal to be checked the latest in
procsignal_sigusr1_handler function.
Are you concerned that one signal will not be processed when multiple
signals are sent in succession?
AFAIU both of them are processed since SendProcSignal flags
ps_signalFlags for each signal.
```
SendProcSignal(pid_t pid, ProcSignalReason reason, BackendId backendId)
{
volatile ProcSignalSlot *slot;
...(snip)...
278 if (slot->pss_pid == pid)
279 {
280 /* Atomically set the proper flag */
281 slot->pss_signalFlags[reason] = true;
282 /* Send signal */
283 return kill(pid, SIGUSR1);
```
Comments of ProcSignalReason also say 'We can cope with concurrent
signals for different reasons'.
```C
/*
* Reasons for signaling a Postgres child process (a backend or an
auxiliary
* process, like checkpointer). We can cope with concurrent signals
for different
* reasons. However, if the same reason is signaled multiple times in
quick
* succession, the process is likely to observe only one notification
of it.
* This is okay for the present uses.
...
typedef enum
{
PROCSIG_CATCHUP_INTERRUPT, /* sinval catchup interrupt */
PROCSIG_NOTIFY_INTERRUPT, /* listen/notify interrupt */
PROCSIG_PARALLEL_MESSAGE, /* message from cooperating parallel
backend */
PROCSIG_WALSND_INIT_STOPPING, /* ask walsenders to prepare for
shutdown */
PROCSIG_BARRIER, /* global barrier interrupt */
PROCSIG_LOG_MEMORY_CONTEXT, /* ask backend to log the memory
contexts */
PROCSIG_LOG_QUERY_PLAN, /* ask backend to log plan of the current
query */
...
} ProcSignalReason;
```
[1]
https://www.postgresql.org/message-id/8b53b32f-26cc-0531-4ac0-27310e0bef4b%40oss.nttdata.com
--
Regards,
--
Atsushi Torikoshi
NTT DATA CORPORATION
From a0d2179826a0fa224eaf37ca00d14954b76fde6b Mon Sep 17 00:00:00 2001
From: Atsushi Torikoshi <torikos...@oss.nttdata.com>
Date: Tue, 20 Sep 2022 21:52:41 +0900
Subject: [PATCH v24] Add function to log the plan of the query
currently running on the backend.
Currently, we have to wait for the query execution to finish
to check its plan. This is not so convenient when
investigating long-running queries on production environments
where we cannot use debuggers.
To improve this situation, this patch adds
pg_log_query_plan() function that requests to log the
plan of the specified backend process.
By default, only superusers are allowed to request to log the
plans because allowing any users to issue this request at an
unbounded rate would cause lots of log messages and which can
lead to denial of service.
On receipt of the request, at the next CHECK_FOR_INTERRUPTS(),
the target backend logs its plan at LOG_SERVER_ONLY level, so
that these plans will appear in the server log but not be sent
to the client.
Reviewed-by: Bharath Rupireddy, Fujii Masao, Dilip Kumar,
Masahiro Ikeda, Ekaterina Sokolova, Justin Pryzby, Kyotaro
Horiguchi, Robert Treat, Alena Rybakina
---
doc/src/sgml/func.sgml | 49 +++++++
src/backend/access/transam/xact.c | 13 ++
src/backend/catalog/system_functions.sql | 2 +
src/backend/commands/explain.c | 140 ++++++++++++++++++-
src/backend/executor/execMain.c | 14 ++
src/backend/storage/ipc/procsignal.c | 4 +
src/backend/storage/lmgr/lock.c | 9 +-
src/backend/tcop/postgres.c | 4 +
src/backend/utils/init/globals.c | 2 +
src/include/catalog/pg_proc.dat | 6 +
src/include/commands/explain.h | 3 +
src/include/miscadmin.h | 1 +
src/include/storage/lock.h | 2 -
src/include/storage/procsignal.h | 1 +
src/include/tcop/pquery.h | 2 +-
src/test/regress/expected/misc_functions.out | 54 +++++--
src/test/regress/sql/misc_functions.sql | 41 ++++--
17 files changed, 318 insertions(+), 29 deletions(-)
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index e1fe4fec57..bd80d062c1 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -25535,6 +25535,25 @@ SELECT collation for ('foo' COLLATE "de_DE");
</para></entry>
</row>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>pg_log_query_plan</primary>
+ </indexterm>
+ <function>pg_log_query_plan</function> ( <parameter>pid</parameter> <type>integer</type> )
+ <returnvalue>boolean</returnvalue>
+ </para>
+ <para>
+ Requests to log the plan of the query currently running on the
+ backend with specified process ID.
+ It will be logged at <literal>LOG</literal> message level and
+ will appear in the server log based on the log
+ configuration set (See <xref linkend="runtime-config-logging"/>
+ for more information), but will not be sent to the client
+ regardless of <xref linkend="guc-client-min-messages"/>.
+ </para></entry>
+ </row>
+
<row>
<entry role="func_table_entry"><para role="func_signature">
<indexterm>
@@ -25649,6 +25668,36 @@ LOG: Grand total: 1651920 bytes in 201 blocks; 622360 free (88 chunks); 1029560
because it may generate a large number of log messages.
</para>
+ <para>
+ <function>pg_log_query_plan</function> can be used
+ to log the plan of a backend process. For example:
+<programlisting>
+postgres=# SELECT pg_log_query_plan(201116);
+ pg_log_query_plan
+---------------------------
+ t
+(1 row)
+</programlisting>
+The format of the query plan is the same as when <literal>VERBOSE</literal>,
+<literal>COSTS</literal>, <literal>SETTINGS</literal> and
+<literal>FORMAT TEXT</literal> are used in the <command>EXPLAIN</command>
+command. For example:
+<screen>
+LOG: query plan running on backend with PID 201116 is:
+ Query Text: SELECT * FROM pgbench_accounts;
+ Seq Scan on public.pgbench_accounts (cost=0.00..52787.00 rows=2000000 width=97)
+ Output: aid, bid, abalance, filler
+ Settings: work_mem = '1MB'
+</screen>
+ Note that when statements are executed inside a function, only the
+ plan of the most deeply nested query is logged.
+ </para>
+
+ <para>
+ When a subtransaction is aborted, <function>pg_log_query_plan</function>
+ cannot log the query plan after the abort.
+ </para>
+
</sect2>
<sect2 id="functions-admin-backup">
diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c
index 2bb975943c..fb698ac007 100644
--- a/src/backend/access/transam/xact.c
+++ b/src/backend/access/transam/xact.c
@@ -60,6 +60,7 @@
#include "storage/procarray.h"
#include "storage/sinvaladt.h"
#include "storage/smgr.h"
+#include "tcop/pquery.h"
#include "utils/builtins.h"
#include "utils/catcache.h"
#include "utils/combocid.h"
@@ -2739,6 +2740,12 @@ AbortTransaction(void)
*/
PG_SETMASK(&UnBlockSig);
+ /*
+ * When ActiveQueryDesc is referenced after abort, some of its elements
+ * are freed. To avoid accessing them, reset ActiveQueryDesc here.
+ */
+ ActiveQueryDesc = NULL;
+
/*
* check the current transaction state
*/
@@ -5072,6 +5079,12 @@ AbortSubTransaction(void)
*/
PG_SETMASK(&UnBlockSig);
+ /*
+ * When ActiveQueryDesc is referenced after abort, some of its elements
+ * are freed. To avoid accessing them, reset ActiveQueryDesc here.
+ */
+ ActiveQueryDesc = NULL;
+
/*
* check the current transaction state
*/
diff --git a/src/backend/catalog/system_functions.sql b/src/backend/catalog/system_functions.sql
index 30a048f6b0..e347e6be90 100644
--- a/src/backend/catalog/system_functions.sql
+++ b/src/backend/catalog/system_functions.sql
@@ -713,6 +713,8 @@ REVOKE EXECUTE ON FUNCTION pg_ls_logicalmapdir() FROM PUBLIC;
REVOKE EXECUTE ON FUNCTION pg_ls_replslotdir(text) FROM PUBLIC;
+REVOKE EXECUTE ON FUNCTION pg_log_query_plan(integer) FROM PUBLIC;
+
--
-- We also set up some things as accessible to standard roles.
--
diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index 053d2ca5ae..9a361e87ac 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -21,6 +21,7 @@
#include "executor/nodeHash.h"
#include "foreign/fdwapi.h"
#include "jit/jit.h"
+#include "miscadmin.h"
#include "nodes/extensible.h"
#include "nodes/makefuncs.h"
#include "nodes/nodeFuncs.h"
@@ -28,6 +29,8 @@
#include "parser/parsetree.h"
#include "rewrite/rewriteHandler.h"
#include "storage/bufmgr.h"
+#include "storage/procarray.h"
+#include "tcop/pquery.h"
#include "tcop/tcopprot.h"
#include "utils/builtins.h"
#include "utils/guc_tables.h"
@@ -40,7 +43,6 @@
#include "utils/typcache.h"
#include "utils/xml.h"
-
/* Hook for plugins to get control in ExplainOneQuery() */
ExplainOneQuery_hook_type ExplainOneQuery_hook = NULL;
@@ -1625,6 +1627,9 @@ ExplainNode(PlanState *planstate, List *ancestors,
/*
* We have to forcibly clean up the instrumentation state because we
* haven't done ExecutorEnd yet. This is pretty grotty ...
+ * This cleanup should not be done when the query has already been
+ * executed and explain has been called by signal, as the target query
+ * may use instrumentation and clean itself up.
*
* Note: contrib/auto_explain could cause instrumentation to be set up
* even though we didn't ask for it here. Be careful not to print any
@@ -1632,7 +1637,7 @@ ExplainNode(PlanState *planstate, List *ancestors,
* InstrEndLoop call anyway, if possible, to reduce the number of cases
* auto_explain has to contend with.
*/
- if (planstate->instrument)
+ if (planstate->instrument && !es->signaled)
InstrEndLoop(planstate->instrument);
if (es->analyze &&
@@ -5041,3 +5046,134 @@ escape_yaml(StringInfo buf, const char *str)
{
escape_json(buf, str);
}
+
+/*
+ * HandleLogQueryPlanInterrupt
+ * Handle receipt of an interrupt indicating logging the plan of
+ * the currently running query.
+ *
+ * All the actual work is deferred to ProcessLogQueryPlanInterrupt(),
+ * because we cannot safely emit a log message inside the signal handler.
+ */
+void
+HandleLogQueryPlanInterrupt(void)
+{
+ InterruptPending = true;
+ LogQueryPlanPending = true;
+ /* latch will be set by procsignal_sigusr1_handler */
+}
+
+/*
+ * ProcessLogQueryPlanInterrupt
+ * Perform logging the plan of the currently running query on this
+ * backend process.
+ *
+ * Any backend that participates in ProcSignal signaling must arrange to call
+ * this function if we see LogQueryPlanPending set.
+ * It is called from CHECK_FOR_INTERRUPTS(), which is enough because the target
+ * process for logging plan is a backend.
+ */
+void
+ProcessLogQueryPlanInterrupt(void)
+{
+ ExplainState *es;
+ HASH_SEQ_STATUS status;
+ LOCALLOCK *locallock;
+ LogQueryPlanPending = false;
+
+ if (ActiveQueryDesc == NULL)
+ {
+ ereport(LOG_SERVER_ONLY,
+ errmsg("backend with PID %d is not running a query or a subtransaction is aborted",
+ MyProcPid),
+ errhidestmt(true),
+ errhidecontext(true));
+ return;
+ }
+
+ /*
+ * Ensure no page lock is held on this process.
+ *
+ * If page lock is held at the time of the interrupt, we can't acquire any
+ * other heavyweight lock, which might be necessary for explaining the plan
+ * when retrieving column names.
+ *
+ * This may be overkill, but since page locks are held for a short duration
+ * we check all the LocalLock entries and when finding even one, give up
+ * logging the plan.
+ */
+ hash_seq_init(&status, GetLockMethodLocalHash());
+ while ((locallock = (LOCALLOCK *) hash_seq_search(&status)) != NULL)
+ {
+ if (LOCALLOCK_LOCKTAG(*locallock) == LOCKTAG_PAGE)
+ {
+ ereport(LOG_SERVER_ONLY,
+ errmsg("ignored request for logging query plan due to lock confilcts"),
+ errdetail("You can try again in a moment."));
+ hash_seq_term(&status);
+ return;
+ }
+ }
+
+ es = NewExplainState();
+
+ es->format = EXPLAIN_FORMAT_TEXT;
+ es->settings = true;
+ es->verbose = true;
+ es->signaled = true;
+
+ ExplainBeginOutput(es);
+ ExplainQueryText(es, ActiveQueryDesc);
+ ExplainPrintPlan(es, ActiveQueryDesc);
+ ExplainPrintJITSummary(es, ActiveQueryDesc);
+ ExplainEndOutput(es);
+
+ /* Remove last line break */
+ if (es->str->len > 0 && es->str->data[es->str->len - 1] == '\n')
+ es->str->data[--es->str->len] = '\0';
+
+ ereport(LOG_SERVER_ONLY,
+ errmsg("query plan running on backend with PID %d is:\n%s",
+ MyProcPid, es->str->data),
+ errhidestmt(true),
+ errhidecontext(true));
+}
+
+/*
+ * pg_log_query_plan
+ * Signal a backend process to log the query plan of the running query.
+ *
+ * By default, only superusers are allowed to signal to log the plan because
+ * allowing any users to issue this request at an unbounded rate would
+ * cause lots of log messages and which can lead to denial of service.
+ * Additional roles can be permitted with GRANT.
+ */
+Datum
+pg_log_query_plan(PG_FUNCTION_ARGS)
+{
+ int pid = PG_GETARG_INT32(0);
+ PGPROC *proc;
+
+ proc = BackendPidGetProc(pid);
+
+ if (proc == NULL)
+ {
+ /*
+ * This is just a warning so a loop-through-resultset will not abort
+ * if one backend terminated on its own during the run.
+ */
+ ereport(WARNING,
+ (errmsg("PID %d is not a PostgreSQL backend process", pid)));
+ PG_RETURN_BOOL(false);
+ }
+
+ if (SendProcSignal(pid, PROCSIG_LOG_QUERY_PLAN, proc->backendId) < 0)
+ {
+ /* Again, just a warning to allow loops */
+ ereport(WARNING,
+ (errmsg("could not send signal to process %d: %m", pid)));
+ PG_RETURN_BOOL(false);
+ }
+
+ PG_RETURN_BOOL(true);
+}
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index d78862e660..1ce107a069 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -77,6 +77,9 @@ ExecutorEnd_hook_type ExecutorEnd_hook = NULL;
/* Hook for plugin to get control in ExecCheckRTPerms() */
ExecutorCheckPerms_hook_type ExecutorCheckPerms_hook = NULL;
+/* Currently executing query's QueryDesc */
+QueryDesc *ActiveQueryDesc = NULL;
+
/* decls for local routines only used within this module */
static void InitPlan(QueryDesc *queryDesc, int eflags);
static void CheckValidRowMarkRel(Relation rel, RowMarkType markType);
@@ -301,10 +304,21 @@ ExecutorRun(QueryDesc *queryDesc,
ScanDirection direction, uint64 count,
bool execute_once)
{
+ /*
+ * Update ActiveQueryDesc here to enable retrieval of the currently
+ * running queryDesc for nested queries.
+ */
+ QueryDesc *save_ActiveQueryDesc;
+
+ save_ActiveQueryDesc = ActiveQueryDesc;
+ ActiveQueryDesc = queryDesc;
+
if (ExecutorRun_hook)
(*ExecutorRun_hook) (queryDesc, direction, count, execute_once);
else
standard_ExecutorRun(queryDesc, direction, count, execute_once);
+
+ ActiveQueryDesc = save_ActiveQueryDesc;
}
void
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 21a9fc0fdd..0b4a591ee7 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -20,6 +20,7 @@
#include "access/parallel.h"
#include "port/pg_bitutils.h"
#include "commands/async.h"
+#include "commands/explain.h"
#include "miscadmin.h"
#include "pgstat.h"
#include "replication/walsender.h"
@@ -657,6 +658,9 @@ procsignal_sigusr1_handler(SIGNAL_ARGS)
if (CheckProcSignal(PROCSIG_LOG_MEMORY_CONTEXT))
HandleLogMemoryContextInterrupt();
+ if (CheckProcSignal(PROCSIG_LOG_QUERY_PLAN))
+ HandleLogQueryPlanInterrupt();
+
if (CheckProcSignal(PROCSIG_RECOVERY_CONFLICT_DATABASE))
RecoveryConflictInterrupt(PROCSIG_RECOVERY_CONFLICT_DATABASE);
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5f5803f681..9beb456f78 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -614,17 +614,18 @@ LockHeldByMe(const LOCKTAG *locktag, LOCKMODE lockmode)
return (locallock && locallock->nLocks > 0);
}
-#ifdef USE_ASSERT_CHECKING
/*
- * GetLockMethodLocalHash -- return the hash of local locks, for modules that
- * evaluate assertions based on all locks held.
+ * GetLockMethodLocalHash -- return the hash of local locks, mainly for
+ * modules that evaluate assertions based on all locks held.
+ *
+ * NOTE: When there are many entries in LockMethodLocalHash, calling this
+ * function and looking into all of them can lead to performance problems.
*/
HTAB *
GetLockMethodLocalHash(void)
{
return LockMethodLocalHash;
}
-#endif
/*
* LockHasWaiters -- look up 'locktag' and check if releasing this
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index 35eff28bd3..053d460ab2 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -33,6 +33,7 @@
#include "access/xact.h"
#include "catalog/pg_type.h"
#include "commands/async.h"
+#include "commands/explain.h"
#include "commands/prepare.h"
#include "common/pg_prng.h"
#include "jit/jit.h"
@@ -3377,6 +3378,9 @@ ProcessInterrupts(void)
if (LogMemoryContextPending)
ProcessLogMemoryContextInterrupt();
+
+ if (LogQueryPlanPending)
+ ProcessLogQueryPlanInterrupt();
}
/*
diff --git a/src/backend/utils/init/globals.c b/src/backend/utils/init/globals.c
index 1a5d29ac9b..ab2fdf80fd 100644
--- a/src/backend/utils/init/globals.c
+++ b/src/backend/utils/init/globals.c
@@ -37,6 +37,8 @@ volatile sig_atomic_t IdleSessionTimeoutPending = false;
volatile sig_atomic_t ProcSignalBarrierPending = false;
volatile sig_atomic_t LogMemoryContextPending = false;
volatile sig_atomic_t IdleStatsUpdateTimeoutPending = false;
+volatile sig_atomic_t LogQueryPlanPending = false;
+
volatile uint32 InterruptHoldoffCount = 0;
volatile uint32 QueryCancelHoldoffCount = 0;
volatile uint32 CritSectionCount = 0;
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index a07e737a33..9a09d77f93 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -8101,6 +8101,12 @@
prorettype => 'bool', proargtypes => 'int4',
prosrc => 'pg_log_backend_memory_contexts' },
+# logging plan of the running query on the specified backend
+{ oid => '4550', descr => 'log plan of the running query on the specified backend',
+ proname => 'pg_log_query_plan',
+ provolatile => 'v', prorettype => 'bool',
+ proargtypes => 'int4', prosrc => 'pg_log_query_plan' },
+
# non-persistent series generator
{ oid => '1066', descr => 'non-persistent series generator',
proname => 'generate_series', prorows => '1000',
diff --git a/src/include/commands/explain.h b/src/include/commands/explain.h
index 9ebde089ae..fc9f9f8e3f 100644
--- a/src/include/commands/explain.h
+++ b/src/include/commands/explain.h
@@ -59,6 +59,7 @@ typedef struct ExplainState
bool hide_workers; /* set if we find an invisible Gather */
/* state related to the current plan node */
ExplainWorkersState *workers_state; /* needed if parallel plan */
+ bool signaled; /* whether explain is called by signal */
} ExplainState;
/* Hook for plugins to get control in ExplainOneQuery() */
@@ -125,4 +126,6 @@ extern void ExplainOpenGroup(const char *objtype, const char *labelname,
extern void ExplainCloseGroup(const char *objtype, const char *labelname,
bool labeled, ExplainState *es);
+extern void HandleLogQueryPlanInterrupt(void);
+extern void ProcessLogQueryPlanInterrupt(void);
#endif /* EXPLAIN_H */
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index ee48e392ed..960366bf93 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -95,6 +95,7 @@ extern PGDLLIMPORT volatile sig_atomic_t IdleSessionTimeoutPending;
extern PGDLLIMPORT volatile sig_atomic_t ProcSignalBarrierPending;
extern PGDLLIMPORT volatile sig_atomic_t LogMemoryContextPending;
extern PGDLLIMPORT volatile sig_atomic_t IdleStatsUpdateTimeoutPending;
+extern PGDLLIMPORT volatile sig_atomic_t LogQueryPlanPending;
extern PGDLLIMPORT volatile sig_atomic_t CheckClientConnectionPending;
extern PGDLLIMPORT volatile sig_atomic_t ClientConnectionLost;
diff --git a/src/include/storage/lock.h b/src/include/storage/lock.h
index e4e1495b24..ae89a104ef 100644
--- a/src/include/storage/lock.h
+++ b/src/include/storage/lock.h
@@ -561,9 +561,7 @@ extern void LockReleaseSession(LOCKMETHODID lockmethodid);
extern void LockReleaseCurrentOwner(LOCALLOCK **locallocks, int nlocks);
extern void LockReassignCurrentOwner(LOCALLOCK **locallocks, int nlocks);
extern bool LockHeldByMe(const LOCKTAG *locktag, LOCKMODE lockmode);
-#ifdef USE_ASSERT_CHECKING
extern HTAB *GetLockMethodLocalHash(void);
-#endif
extern bool LockHasWaiters(const LOCKTAG *locktag,
LOCKMODE lockmode, bool sessionLock);
extern VirtualTransactionId *GetLockConflicts(const LOCKTAG *locktag,
diff --git a/src/include/storage/procsignal.h b/src/include/storage/procsignal.h
index ee636900f3..dc8fd66466 100644
--- a/src/include/storage/procsignal.h
+++ b/src/include/storage/procsignal.h
@@ -35,6 +35,7 @@ typedef enum
PROCSIG_WALSND_INIT_STOPPING, /* ask walsenders to prepare for shutdown */
PROCSIG_BARRIER, /* global barrier interrupt */
PROCSIG_LOG_MEMORY_CONTEXT, /* ask backend to log the memory contexts */
+ PROCSIG_LOG_QUERY_PLAN, /* ask backend to log plan of the current query */
/* Recovery conflict reasons */
PROCSIG_RECOVERY_CONFLICT_DATABASE,
diff --git a/src/include/tcop/pquery.h b/src/include/tcop/pquery.h
index f9a6882ecb..4a0e94ab1a 100644
--- a/src/include/tcop/pquery.h
+++ b/src/include/tcop/pquery.h
@@ -21,7 +21,7 @@ struct PlannedStmt; /* avoid including plannodes.h here */
extern PGDLLIMPORT Portal ActivePortal;
-
+extern PGDLLIMPORT QueryDesc *ActiveQueryDesc;
extern PortalStrategy ChoosePortalStrategy(List *stmts);
diff --git a/src/test/regress/expected/misc_functions.out b/src/test/regress/expected/misc_functions.out
index 9f106c2a10..62196d0a39 100644
--- a/src/test/regress/expected/misc_functions.out
+++ b/src/test/regress/expected/misc_functions.out
@@ -276,14 +276,15 @@ SELECT test_canonicalize_path('./abc/./def/.././ghi/../../../jkl/mno');
../jkl/mno
(1 row)
+-- Test logging functions
--
--- pg_log_backend_memory_contexts()
---
--- Memory contexts are logged and they are not returned to the function.
+-- The outputs of these functions are logged and they are not returned to
+-- the function.
-- Furthermore, their contents can vary depending on the timing. However,
-- we can at least verify that the code doesn't fail, and that the
-- permissions are set properly.
--
+-- pg_log_backend_memory_contexts()
SELECT pg_log_backend_memory_contexts(pg_backend_pid());
pg_log_backend_memory_contexts
--------------------------------
@@ -297,8 +298,8 @@ SELECT pg_log_backend_memory_contexts(pid) FROM pg_stat_activity
t
(1 row)
-CREATE ROLE regress_log_memory;
-SELECT has_function_privilege('regress_log_memory',
+CREATE ROLE regress_log_function;
+SELECT has_function_privilege('regress_log_function',
'pg_log_backend_memory_contexts(integer)', 'EXECUTE'); -- no
has_function_privilege
------------------------
@@ -306,15 +307,15 @@ SELECT has_function_privilege('regress_log_memory',
(1 row)
GRANT EXECUTE ON FUNCTION pg_log_backend_memory_contexts(integer)
- TO regress_log_memory;
-SELECT has_function_privilege('regress_log_memory',
+ TO regress_log_function;
+SELECT has_function_privilege('regress_log_function',
'pg_log_backend_memory_contexts(integer)', 'EXECUTE'); -- yes
has_function_privilege
------------------------
t
(1 row)
-SET ROLE regress_log_memory;
+SET ROLE regress_log_function;
SELECT pg_log_backend_memory_contexts(pg_backend_pid());
pg_log_backend_memory_contexts
--------------------------------
@@ -323,8 +324,41 @@ SELECT pg_log_backend_memory_contexts(pg_backend_pid());
RESET ROLE;
REVOKE EXECUTE ON FUNCTION pg_log_backend_memory_contexts(integer)
- FROM regress_log_memory;
-DROP ROLE regress_log_memory;
+ FROM regress_log_function;
+-- pg_log_query_plan()
+SELECT pg_log_query_plan(pg_backend_pid());
+ pg_log_query_plan
+-------------------
+ t
+(1 row)
+
+SELECT has_function_privilege('regress_log_function',
+ 'pg_log_query_plan(integer)', 'EXECUTE'); -- no
+ has_function_privilege
+------------------------
+ f
+(1 row)
+
+GRANT EXECUTE ON FUNCTION pg_log_query_plan(integer)
+ TO regress_log_function;
+SELECT has_function_privilege('regress_log_function',
+ 'pg_log_query_plan(integer)', 'EXECUTE'); -- yes
+ has_function_privilege
+------------------------
+ t
+(1 row)
+
+SET ROLE regress_log_function;
+SELECT pg_log_query_plan(pg_backend_pid());
+ pg_log_query_plan
+-------------------
+ t
+(1 row)
+
+RESET ROLE;
+REVOKE EXECUTE ON FUNCTION pg_log_query_plan(integer)
+ FROM regress_log_function;
+DROP ROLE regress_log_function;
--
-- Test some built-in SRFs
--
diff --git a/src/test/regress/sql/misc_functions.sql b/src/test/regress/sql/misc_functions.sql
index 639e9b352c..43b78a23fc 100644
--- a/src/test/regress/sql/misc_functions.sql
+++ b/src/test/regress/sql/misc_functions.sql
@@ -68,39 +68,60 @@ SELECT test_canonicalize_path('./abc/./def/.');
SELECT test_canonicalize_path('./abc/././def/.');
SELECT test_canonicalize_path('./abc/./def/.././ghi/../../../jkl/mno');
+-- Test logging functions
--
--- pg_log_backend_memory_contexts()
---
--- Memory contexts are logged and they are not returned to the function.
+-- The outputs of these functions are logged and they are not returned to
+-- the function.
-- Furthermore, their contents can vary depending on the timing. However,
-- we can at least verify that the code doesn't fail, and that the
-- permissions are set properly.
--
+-- pg_log_backend_memory_contexts()
+
SELECT pg_log_backend_memory_contexts(pg_backend_pid());
SELECT pg_log_backend_memory_contexts(pid) FROM pg_stat_activity
WHERE backend_type = 'checkpointer';
-CREATE ROLE regress_log_memory;
+CREATE ROLE regress_log_function;
-SELECT has_function_privilege('regress_log_memory',
+SELECT has_function_privilege('regress_log_function',
'pg_log_backend_memory_contexts(integer)', 'EXECUTE'); -- no
GRANT EXECUTE ON FUNCTION pg_log_backend_memory_contexts(integer)
- TO regress_log_memory;
+ TO regress_log_function;
-SELECT has_function_privilege('regress_log_memory',
+SELECT has_function_privilege('regress_log_function',
'pg_log_backend_memory_contexts(integer)', 'EXECUTE'); -- yes
-SET ROLE regress_log_memory;
+SET ROLE regress_log_function;
SELECT pg_log_backend_memory_contexts(pg_backend_pid());
RESET ROLE;
REVOKE EXECUTE ON FUNCTION pg_log_backend_memory_contexts(integer)
- FROM regress_log_memory;
+ FROM regress_log_function;
+
+-- pg_log_query_plan()
+SELECT pg_log_query_plan(pg_backend_pid());
+
+SELECT has_function_privilege('regress_log_function',
+ 'pg_log_query_plan(integer)', 'EXECUTE'); -- no
+
+GRANT EXECUTE ON FUNCTION pg_log_query_plan(integer)
+ TO regress_log_function;
+
+SELECT has_function_privilege('regress_log_function',
+ 'pg_log_query_plan(integer)', 'EXECUTE'); -- yes
+
+SET ROLE regress_log_function;
+SELECT pg_log_query_plan(pg_backend_pid());
+RESET ROLE;
+
+REVOKE EXECUTE ON FUNCTION pg_log_query_plan(integer)
+ FROM regress_log_function;
-DROP ROLE regress_log_memory;
+DROP ROLE regress_log_function;
--
-- Test some built-in SRFs
--
2.27.0
