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fixing repmgr repl_status columns

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repmgr repl_status had the column time_lag which was documented to be
the time a standby is behind master. In fact it only works like this
when viewed on the standby and not on the master: there it only was the
time of the last status update. We dropped that column and replaced it
by a new column „communication_time_lag“ which is the content of the
repl_status column on the master. On the standby we contain the time of
the last update in shared mem though refer always to the correct time
nonetheless where repl_status is queried. We also added a new column,
„replication_time_lag“, which refers to the apply delay.
This commit is contained in:
Christian Kruse
2014-02-15 01:35:27 +01:00
parent 18f1fed77f
commit c3b58658ad
5 changed files with 99 additions and 5 deletions
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35
repmgr.c
View File

@@ -2089,6 +2089,35 @@ create_schema(PGconn *conn)
}
PQclear(res);
/* to avoid confusion of the time_lag field and provide a consistent UI we
* use these functions for providing the latest update timestamp */
sqlquery_snprintf(sqlquery,
"CREATE FUNCTION %s.repmgr_update_last_updated() RETURNS TIMESTAMP WITH TIME ZONE "
"AS '$libdir/repmgr_funcs', 'repmgr_update_last_updated' "
" LANGUAGE C STRICT", repmgr_schema);
res = PQexec(conn, sqlquery);
if (!res || PQresultStatus(res) != PGRES_COMMAND_OK)
{
fprintf(stderr, "Cannot create the function repmgr_update_last_updated: %s\n",
PQerrorMessage(conn));
return false;
}
PQclear(res);
sqlquery_snprintf(sqlquery,
"CREATE FUNCTION %s.repmgr_get_last_updated() RETURNS TIMESTAMP WITH TIME ZONE "
"AS '$libdir/repmgr_funcs', 'repmgr_get_last_updated' "
"LANGUAGE C STRICT", repmgr_schema);
res = PQexec(conn, sqlquery);
if (!res || PQresultStatus(res) != PGRES_COMMAND_OK)
{
fprintf(stderr, "Cannot create the function repmgr_get_last_updated: %s\n",
PQerrorMessage(conn));
return false;
}
PQclear(res);
/* ... the tables */
sqlquery_snprintf(sqlquery, "CREATE TABLE %s.repl_nodes ( "
@@ -2113,6 +2142,7 @@ create_schema(PGconn *conn)
" primary_node INTEGER NOT NULL, "
" standby_node INTEGER NOT NULL, "
" last_monitor_time TIMESTAMP WITH TIME ZONE NOT NULL, "
" last_apply_time TIMESTAMP WITH TIME ZONE, "
" last_wal_primary_location TEXT NOT NULL, "
" last_wal_standby_location TEXT, "
" replication_lag BIGINT NOT NULL, "
@@ -2133,12 +2163,13 @@ create_schema(PGconn *conn)
" SELECT primary_node, standby_node, name AS standby_name, last_monitor_time, "
" last_wal_primary_location, last_wal_standby_location, "
" pg_size_pretty(replication_lag) replication_lag, "
" age(now(), last_apply_time) AS replication_time_lag, "
" pg_size_pretty(apply_lag) apply_lag, "
" age(now(), last_monitor_time) AS time_lag "
" age(now(), CASE WHEN pg_is_in_recovery() THEN %s.repmgr_get_last_updated() ELSE last_monitor_time END) AS communication_time_lag "
" FROM %s.repl_monitor JOIN %s.repl_nodes ON standby_node = id "
" WHERE (standby_node, last_monitor_time) IN (SELECT standby_node, MAX(last_monitor_time) "
" FROM %s.repl_monitor GROUP BY 1)",
repmgr_schema, repmgr_schema, repmgr_schema, repmgr_schema);
repmgr_schema, repmgr_schema, repmgr_schema, repmgr_schema, repmgr_schema);
log_debug(_("master register: %s\n"), sqlquery);
res = PQexec(conn, sqlquery);

7
repmgrd.c
View File

@@ -530,6 +530,7 @@ StandbyMonitor(void)
char last_wal_primary_location[MAXLEN];
char last_wal_standby_received[MAXLEN];
char last_wal_standby_applied[MAXLEN];
char last_wal_standby_applied_timestamp[MAXLEN];
unsigned long long int lsn_primary;
unsigned long long int lsn_standby_received;
@@ -637,7 +638,7 @@ StandbyMonitor(void)
sqlquery_snprintf(
sqlquery,
"SELECT CURRENT_TIMESTAMP, pg_last_xlog_receive_location(), "
"pg_last_xlog_replay_location()");
"pg_last_xlog_replay_location(), pg_last_xact_replay_timestamp()");
res = PQexec(myLocalConn, sqlquery);
if (PQresultStatus(res) != PGRES_TUPLES_OK)
@@ -651,6 +652,7 @@ StandbyMonitor(void)
strncpy(monitor_standby_timestamp, PQgetvalue(res, 0, 0), MAXLEN);
strncpy(last_wal_standby_received , PQgetvalue(res, 0, 1), MAXLEN);
strncpy(last_wal_standby_applied , PQgetvalue(res, 0, 2), MAXLEN);
strncpy(last_wal_standby_applied_timestamp, PQgetvalue(res, 0, 3), MAXLEN);
PQclear(res);
/* Get primary xlog info */
@@ -678,9 +680,10 @@ StandbyMonitor(void)
sqlquery_snprintf(sqlquery,
"INSERT INTO %s.repl_monitor "
"VALUES(%d, %d, '%s'::timestamp with time zone, "
" '%s', '%s', "
" '%s'::timestamp with time zone, '%s', '%s', "
" %lld, %lld)", repmgr_schema,
primary_options.node, local_options.node, monitor_standby_timestamp,
last_wal_standby_applied_timestamp,
last_wal_primary_location,
last_wal_standby_received,
(lsn_primary - lsn_standby_received),

43
sql/repmgr_funcs.c
View File

@@ -15,6 +15,7 @@
#include "storage/shmem.h"
#include "storage/spin.h"
#include "utils/builtins.h"
#include "utils/timestamp.h"
/* same definition as the one in xlog_internal.h */
#define MAXFNAMELEN 64
@@ -28,6 +29,7 @@ typedef struct repmgrSharedState
{
LWLockId lock; /* protects search/modification */
char location[MAXFNAMELEN]; /* last known xlog location */
TimestampTz last_updated;
} repmgrSharedState;
/* Links to shared memory state */
@@ -49,6 +51,12 @@ Datum repmgr_get_last_standby_location(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(repmgr_update_standby_location);
PG_FUNCTION_INFO_V1(repmgr_get_last_standby_location);
Datum repmgr_update_last_updated(PG_FUNCTION_ARGS);
Datum repmgr_get_last_updated(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(repmgr_update_last_updated);
PG_FUNCTION_INFO_V1(repmgr_get_last_updated);
/*
* Module load callback
@@ -187,3 +195,38 @@ repmgr_update_standby_location(PG_FUNCTION_ARGS)
PG_RETURN_BOOL(repmgr_set_standby_location(locationstr));
}
/* update and return last updated with current timestamp */
Datum
repmgr_update_last_updated(PG_FUNCTION_ARGS)
{
TimestampTz last_updated = GetCurrentTimestamp();
/* Safety check... */
if (!shared_state)
PG_RETURN_NULL();
LWLockAcquire(shared_state->lock, LW_SHARED);
shared_state->last_updated = last_updated;
LWLockRelease(shared_state->lock);
PG_RETURN_TIMESTAMPTZ(last_updated);
}
/* get last updated timestamp */
Datum
repmgr_get_last_updated(PG_FUNCTION_ARGS)
{
TimestampTz last_updated;
/* Safety check... */
if (!shared_state)
PG_RETURN_NULL();
LWLockAcquire(shared_state->lock, LW_EXCLUSIVE);
last_updated = shared_state->last_updated;
LWLockRelease(shared_state->lock);
PG_RETURN_TIMESTAMPTZ(last_updated);
}

10
sql/repmgr_funcs.sql.in
View File

@@ -1,6 +1,6 @@
/*
* repmgr_function.sql
* Copyright (c) 2ndQuadrant, 2010
* Copyright (c) 2ndQuadrant, 2010-2014
*
*/
@@ -13,3 +13,11 @@ LANGUAGE C STRICT;
CREATE FUNCTION repmgr_get_last_standby_location() RETURNS text
AS 'MODULE_PATHNAME', 'repmgr_get_last_standby_location'
LANGUAGE C STRICT;
CREATE FUNCTION repmgr_update_last_updated() RETURNS TIMESTAMP WITH TIME ZONE
AS 'MODULE_PATHNAME', 'repmgr_update_last_updated'
LANGUAGE C STRICT;
CREATE FUNCTION repmgr_get_last_updated() RETURNS TIMESTAMP WITH TIME ZONE
AS 'MODULE_PATHNAME', 'repmgr_get_last_updated'
LANGUAGE C STRICT;

9
sql/uninstall_repmgr_funcs.sql
View File

@@ -1,2 +1,11 @@
/*
* uninstall_repmgr_funcs.sql
* Copyright (c) 2ndQuadrant, 2010-2014
*
*/
DROP FUNCTION repmgr_update_standby_location(text);
DROP FUNCTION repmgr_get_last_standby_location();
DROP FUNCTION repmgr_update_last_updated();
DROP FUNCTION repmgr_get_last_updated();