Add client_hostname field to pg_stat_activity.

Peter Eisentraut, reviewed by Steve Singer, Alvaro Herrera, and me.

doc/src/sgml/monitoring.sgml

@@ -245,14 +245,17 @@ postgres: <replaceable>user</> <replaceable>database</> <replaceable>host</> <re
       <entry><structname>pg_stat_activity</><indexterm><primary>pg_stat_activity</primary></indexterm></entry>
       <entry>One row per server process, showing database OID, database
       name, process <acronym>ID</>, user OID, user name, application name,
-      client's address and port number, times at which the server process,
-      current transaction, and current query began execution, process's waiting
-      status, and text of the current query.
+      client's address, hostname (if available), and port number, times at
+      which the server process, current transaction, and current query began
+      execution, process's waiting status, and text of the current query.
       The columns that report data on the current query are available unless
       the parameter <varname>track_activities</varname> has been turned off.
       Furthermore, these columns are only visible if the user examining
       the view is a superuser or the same as the user owning the process
-      being reported on.
+      being reported on.  The client's hostname will be available only if
+      <xref linkend="guc-log-hostname"> is set or if the user's hostname
+      needed to be looked up during <filename>pg_hba.conf</filename>
+      processing.
      </entry>
      </row>
 
@@ -297,14 +300,18 @@ postgres: <replaceable>user</> <replaceable>database</> <replaceable>host</> <re
      <row>
       <entry><structname>pg_stat_replication</><indexterm><primary>pg_stat_replication</primary></indexterm></entry>
       <entry>One row per WAL sender process, showing process <acronym>ID</>,
-      user OID, user name, application name, client's address and port number,
-      time at which the server process began execution, and the current WAL
-      sender state and transaction log location.  In addition, the standby
-      reports the last transaction log position it received and wrote, the last
-      position it flushed to disk, and the last position it replayed, and this
-      information is also displayed here.  The columns detailing what exactly
-      the connection is doing are only visible if the user examining the view
-      is a superuser.
+      user OID, user name, application name, client's address, hostname
+      (if available) and port number, time at which the server process began
+      execution, and the current WAL sender state and transaction log
+      location.  In addition, the standby reports the last transaction log
+      position it received and wrote, the last position it flushed to disk,
+      and the last position it replayed, and this information is also
+      displayed here.  The columns detailing what exactly the connection is
+      doing are only visible if the user examining the view is a superuser.
+      The client's hostname will be available only if
+      <xref linkend="guc-log-hostname"> is set or if the user's hostname
+      needed to be looked up during <filename>pg_hba.conf</filename>
+      processing.
      </entry>
      </row>
 

src/backend/catalog/system_views.sql

@@ -495,6 +495,7 @@ CREATE VIEW pg_stat_activity AS
             U.rolname AS usename,
             S.application_name,
             S.client_addr,
+            S.client_hostname,
             S.client_port,
             S.backend_start,
             S.xact_start,
@@ -512,6 +513,7 @@ CREATE VIEW pg_stat_replication AS
             U.rolname AS usename,
             S.application_name,
             S.client_addr,
+            S.client_hostname,
             S.client_port,
             S.backend_start,
             W.state,

src/backend/postmaster/pgstat.c

@@ -2223,6 +2223,7 @@ pgstat_fetch_global(void)
 
 static PgBackendStatus *BackendStatusArray = NULL;
 static PgBackendStatus *MyBEEntry = NULL;
+static char *BackendClientHostnameBuffer = NULL;
 static char *BackendAppnameBuffer = NULL;
 static char *BackendActivityBuffer = NULL;
 
@@ -2240,11 +2241,13 @@ BackendStatusShmemSize(void)
 					mul_size(NAMEDATALEN, MaxBackends));
 	size = add_size(size,
 					mul_size(pgstat_track_activity_query_size, MaxBackends));
+	size = add_size(size,
+					mul_size(NAMEDATALEN, MaxBackends));
 	return size;
 }
 
 /*
- * Initialize the shared status array and activity/appname string buffers
+ * Initialize the shared status array and several string buffers
  * during postmaster startup.
  */
 void
@@ -2286,6 +2289,24 @@ CreateSharedBackendStatus(void)
 		}
 	}
 
+	/* Create or attach to the shared client hostname buffer */
+	size = mul_size(NAMEDATALEN, MaxBackends);
+	BackendClientHostnameBuffer = (char *)
+		ShmemInitStruct("Backend Client Host Name Buffer", size, &found);
+
+	if (!found)
+	{
+		MemSet(BackendClientHostnameBuffer, 0, size);
+
+		/* Initialize st_clienthostname pointers. */
+		buffer = BackendClientHostnameBuffer;
+		for (i = 0; i < MaxBackends; i++)
+		{
+			BackendStatusArray[i].st_clienthostname = buffer;
+			buffer += NAMEDATALEN;
+		}
+	}
+
 	/* Create or attach to the shared activity buffer */
 	size = mul_size(pgstat_track_activity_query_size, MaxBackends);
 	BackendActivityBuffer = (char *)
@@ -2386,16 +2407,21 @@ pgstat_bestart(void)
 	beentry->st_databaseid = MyDatabaseId;
 	beentry->st_userid = userid;
 	beentry->st_clientaddr = clientaddr;
+	beentry->st_clienthostname[0] = '\0';
 	beentry->st_waiting = false;
 	beentry->st_appname[0] = '\0';
 	beentry->st_activity[0] = '\0';
 	/* Also make sure the last byte in each string area is always 0 */
+	beentry->st_clienthostname[NAMEDATALEN - 1] = '\0';
 	beentry->st_appname[NAMEDATALEN - 1] = '\0';
 	beentry->st_activity[pgstat_track_activity_query_size - 1] = '\0';
 
 	beentry->st_changecount++;
 	Assert((beentry->st_changecount & 1) == 0);
 
+	if (MyProcPort && MyProcPort->remote_hostname)
+		strlcpy(beentry->st_clienthostname, MyProcPort->remote_hostname, NAMEDATALEN);
+
 	/* Update app name to current GUC setting */
 	if (application_name)
 		pgstat_report_appname(application_name);

src/backend/utils/adt/pgstatfuncs.c

@@ -506,7 +506,7 @@ pg_stat_get_activity(PG_FUNCTION_ARGS)
 
 		oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
 
-		tupdesc = CreateTemplateTupleDesc(11, false);
+		tupdesc = CreateTemplateTupleDesc(12, false);
 		TupleDescInitEntry(tupdesc, (AttrNumber) 1, "datid", OIDOID, -1, 0);
 		TupleDescInitEntry(tupdesc, (AttrNumber) 2, "procpid", INT4OID, -1, 0);
 		TupleDescInitEntry(tupdesc, (AttrNumber) 3, "usesysid", OIDOID, -1, 0);
@@ -517,7 +517,8 @@ pg_stat_get_activity(PG_FUNCTION_ARGS)
 		TupleDescInitEntry(tupdesc, (AttrNumber) 8, "query_start", TIMESTAMPTZOID, -1, 0);
 		TupleDescInitEntry(tupdesc, (AttrNumber) 9, "backend_start", TIMESTAMPTZOID, -1, 0);
 		TupleDescInitEntry(tupdesc, (AttrNumber) 10, "client_addr", INETOID, -1, 0);
-		TupleDescInitEntry(tupdesc, (AttrNumber) 11, "client_port", INT4OID, -1, 0);
+		TupleDescInitEntry(tupdesc, (AttrNumber) 11, "client_hostname", TEXTOID, -1, 0);
+		TupleDescInitEntry(tupdesc, (AttrNumber) 12, "client_port", INT4OID, -1, 0);
 
 		funcctx->tuple_desc = BlessTupleDesc(tupdesc);
 
@@ -569,8 +570,8 @@ pg_stat_get_activity(PG_FUNCTION_ARGS)
 	if (funcctx->call_cntr < funcctx->max_calls)
 	{
 		/* for each row */
-		Datum		values[11];
-		bool		nulls[11];
+		Datum		values[12];
+		bool		nulls[12];
 		HeapTuple	tuple;
 		PgBackendStatus *beentry;
 		SockAddr	zero_clientaddr;
@@ -647,6 +648,7 @@ pg_stat_get_activity(PG_FUNCTION_ARGS)
 			{
 				nulls[9] = true;
 				nulls[10] = true;
+				nulls[11] = true;
 			}
 			else
 			{
@@ -671,13 +673,18 @@ pg_stat_get_activity(PG_FUNCTION_ARGS)
 					{
 						nulls[9] = true;
 						nulls[10] = true;
+						nulls[11] = true;
 					}
 					else
 					{
 						clean_ipv6_addr(beentry->st_clientaddr.addr.ss_family, remote_host);
 						values[9] = DirectFunctionCall1(inet_in,
 											   CStringGetDatum(remote_host));
-						values[10] = Int32GetDatum(atoi(remote_port));
+						if (beentry->st_clienthostname)
+							values[10] = CStringGetTextDatum(beentry->st_clienthostname);
+						else
+							nulls[10] = true;
+						values[11] = Int32GetDatum(atoi(remote_port));
 					}
 				}
 				else if (beentry->st_clientaddr.addr.ss_family == AF_UNIX)
@@ -689,13 +696,15 @@ pg_stat_get_activity(PG_FUNCTION_ARGS)
 					 * errors.
 					 */
 					nulls[9] = true;
-					values[10] = DatumGetInt32(-1);
+					nulls[10] = true;
+					values[11] = DatumGetInt32(-1);
 				}
 				else
 				{
 					/* Unknown address type, should never happen */
 					nulls[9] = true;
 					nulls[10] = true;
+					nulls[11] = true;
 				}
 			}
 		}
@@ -709,6 +718,7 @@ pg_stat_get_activity(PG_FUNCTION_ARGS)
 			nulls[8] = true;
 			nulls[9] = true;
 			nulls[10] = true;
+			nulls[11] = true;
 		}
 
 		tuple = heap_form_tuple(funcctx->tuple_desc, values, nulls);

src/include/catalog/catversion.h

@@ -53,6 +53,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	201102161
+#define CATALOG_VERSION_NO	201102171
 
 #endif

src/include/catalog/pg_proc.h

@@ -3073,7 +3073,7 @@ DATA(insert OID = 3057 ( pg_stat_get_autoanalyze_count PGNSP PGUID 12 1 0 0 f f
 DESCR("statistics: number of auto analyzes for a table");
 DATA(insert OID = 1936 (  pg_stat_get_backend_idset		PGNSP PGUID 12 1 100 0 f f f t t s 0 0 23 "" _null_ _null_ _null_ _null_ pg_stat_get_backend_idset _null_ _null_ _null_ ));
 DESCR("statistics: currently active backend IDs");
-DATA(insert OID = 2022 (  pg_stat_get_activity			PGNSP PGUID 12 1 100 0 f f f f t s 1 0 2249 "23" "{23,26,23,26,25,25,16,1184,1184,1184,869,23}" "{i,o,o,o,o,o,o,o,o,o,o,o}" "{pid,datid,procpid,usesysid,application_name,current_query,waiting,xact_start,query_start,backend_start,client_addr,client_port}" _null_ pg_stat_get_activity _null_ _null_ _null_ ));
+DATA(insert OID = 2022 (  pg_stat_get_activity			PGNSP PGUID 12 1 100 0 f f f f t s 1 0 2249 "23" "{23,26,23,26,25,25,16,1184,1184,1184,869,25,23}" "{i,o,o,o,o,o,o,o,o,o,o,o,o}" "{pid,datid,procpid,usesysid,application_name,current_query,waiting,xact_start,query_start,backend_start,client_addr,client_hostname,client_port}" _null_ pg_stat_get_activity _null_ _null_ _null_ ));
 DESCR("statistics: information about currently active backends");
 DATA(insert OID = 3099 (  pg_stat_get_wal_senders	PGNSP PGUID 12 1 10 0 f f f f t s 0 0 2249 "" "{23,25,25,25,25,25}" "{o,o,o,o,o,o}" "{procpid,state,sent_location,write_location,flush_location,apply_location}" _null_ pg_stat_get_wal_senders _null_ _null_ _null_ ));
 DESCR("statistics: information about currently active replication");

src/include/pgstat.h

@@ -628,6 +628,7 @@ typedef struct PgBackendStatus
 	Oid			st_databaseid;
 	Oid			st_userid;
 	SockAddr	st_clientaddr;
+	char	   *st_clienthostname; /* MUST be null-terminated */
 
 	/* Is backend currently waiting on an lmgr lock? */
 	bool		st_waiting;