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repmgr/repmgr--4.2.sql
Ian Barwick 2491b8ae52 Add functionality to "pause" repmgrd
In some circumstances, e.g. while performing a switchover, it is essential
that repmgrd does not take any kind of failover action, as this will put
the cluster into an incorrect state.

Previously it was necessary to stop repmgrd on all nodes (or at least
those nodes which repmgrd would consider as promotion candidates), however
this is a cumbersome and potentially risk-prone operation, particularly if the
replication cluster contains more than a couple of servers.

To prevent this issue from occurring, this patch introduces the ability
to "pause" repmgrd on all nodes wth a single command ("repmgr daemon pause")
which notifies repmgrd not to take any failover action until the node
is "unpaused" ("repmgr daemon unpause").

"repmgr daemon status" provides an overview of each node and whether repmgrd
is running, and if so whether it is paused.

"repmgr standby switchover" has been modified to automatically pause repmgrd
while carrying out the switchover.

See documentation for further details.
2018-09-27 16:42:10 +09:00

198 lines
6.0 KiB
SQL

-- complain if script is sourced in psql, rather than via CREATE EXTENSION
\echo Use "CREATE EXTENSION repmgr" to load this file. \quit
CREATE TABLE repmgr.nodes (
node_id INTEGER PRIMARY KEY,
upstream_node_id INTEGER NULL REFERENCES nodes (node_id) DEFERRABLE,
active BOOLEAN NOT NULL DEFAULT TRUE,
node_name TEXT NOT NULL,
type TEXT NOT NULL CHECK (type IN('primary','standby','witness','bdr')),
location TEXT NOT NULL DEFAULT 'default',
priority INT NOT NULL DEFAULT 100,
conninfo TEXT NOT NULL,
repluser VARCHAR(63) NOT NULL,
slot_name TEXT NULL,
config_file TEXT NOT NULL
);
CREATE TABLE repmgr.events (
node_id INTEGER NOT NULL,
event TEXT NOT NULL,
successful BOOLEAN NOT NULL DEFAULT TRUE,
event_timestamp TIMESTAMP WITH TIME ZONE NOT NULL DEFAULT CURRENT_TIMESTAMP,
details TEXT NULL
);
DO $repmgr$
DECLARE
DECLARE server_version_num INT;
BEGIN
SELECT setting
FROM pg_catalog.pg_settings
WHERE name = 'server_version_num'
INTO server_version_num;
IF server_version_num >= 90400 THEN
EXECUTE $repmgr_func$
CREATE TABLE repmgr.monitoring_history (
primary_node_id INTEGER NOT NULL,
standby_node_id INTEGER NOT NULL,
last_monitor_time TIMESTAMP WITH TIME ZONE NOT NULL,
last_apply_time TIMESTAMP WITH TIME ZONE,
last_wal_primary_location PG_LSN NOT NULL,
last_wal_standby_location PG_LSN,
replication_lag BIGINT NOT NULL,
apply_lag BIGINT NOT NULL
)
$repmgr_func$;
ELSE
EXECUTE $repmgr_func$
CREATE TABLE repmgr.monitoring_history (
primary_node_id INTEGER NOT NULL,
standby_node_id 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,
apply_lag BIGINT NOT NULL
)
$repmgr_func$;
END IF;
END$repmgr$;
CREATE INDEX idx_monitoring_history_time
ON repmgr.monitoring_history (last_monitor_time, standby_node_id);
CREATE VIEW repmgr.show_nodes AS
SELECT n.node_id,
n.node_name,
n.active,
n.upstream_node_id,
un.node_name AS upstream_node_name,
n.type,
n.priority,
n.conninfo
FROM repmgr.nodes n
LEFT JOIN repmgr.nodes un
ON un.node_id = n.upstream_node_id;
/* XXX update upgrade scripts! */
CREATE TABLE repmgr.voting_term (
term INT NOT NULL
);
CREATE UNIQUE INDEX voting_term_restrict
ON repmgr.voting_term ((TRUE));
CREATE RULE voting_term_delete AS
ON DELETE TO repmgr.voting_term
DO INSTEAD NOTHING;
/* ================= */
/* repmgrd functions */
/* ================= */
/* monitoring functions */
CREATE FUNCTION set_local_node_id(INT)
RETURNS VOID
AS 'MODULE_PATHNAME', 'set_local_node_id'
LANGUAGE C STRICT;
CREATE FUNCTION get_local_node_id()
RETURNS INT
AS 'MODULE_PATHNAME', 'get_local_node_id'
LANGUAGE C STRICT;
CREATE FUNCTION standby_set_last_updated()
RETURNS TIMESTAMP WITH TIME ZONE
AS 'MODULE_PATHNAME', 'standby_set_last_updated'
LANGUAGE C STRICT;
CREATE FUNCTION standby_get_last_updated()
RETURNS TIMESTAMP WITH TIME ZONE
AS 'MODULE_PATHNAME', 'standby_get_last_updated'
LANGUAGE C STRICT;
/* failover functions */
CREATE FUNCTION notify_follow_primary(INT)
RETURNS VOID
AS 'MODULE_PATHNAME', 'notify_follow_primary'
LANGUAGE C STRICT;
CREATE FUNCTION get_new_primary()
RETURNS INT
AS 'MODULE_PATHNAME', 'get_new_primary'
LANGUAGE C STRICT;
CREATE FUNCTION reset_voting_status()
RETURNS VOID
AS 'MODULE_PATHNAME', 'reset_voting_status'
LANGUAGE C STRICT;
CREATE FUNCTION am_bdr_failover_handler(INT)
RETURNS BOOL
AS 'MODULE_PATHNAME', 'am_bdr_failover_handler'
LANGUAGE C STRICT;
CREATE FUNCTION unset_bdr_failover_handler()
RETURNS VOID
AS 'MODULE_PATHNAME', 'unset_bdr_failover_handler'
LANGUAGE C STRICT;
CREATE FUNCTION get_repmgrd_pid()
RETURNS INT
AS 'MODULE_PATHNAME', 'get_repmgrd_pid'
LANGUAGE C STRICT;
CREATE FUNCTION get_repmgrd_pidfile()
RETURNS TEXT
AS 'MODULE_PATHNAME', 'get_repmgrd_pidfile'
LANGUAGE C STRICT;
CREATE FUNCTION set_repmgrd_pid(INT, TEXT)
RETURNS VOID
AS 'MODULE_PATHNAME', 'set_repmgrd_pid'
LANGUAGE C STRICT;
CREATE FUNCTION repmgrd_is_running()
RETURNS BOOL
AS 'MODULE_PATHNAME', 'repmgrd_is_running'
LANGUAGE C STRICT;
CREATE FUNCTION repmgrd_pause(BOOL)
RETURNS VOID
AS 'MODULE_PATHNAME', 'repmgrd_pause'
LANGUAGE C STRICT;
CREATE FUNCTION repmgrd_is_paused()
RETURNS BOOL
AS 'MODULE_PATHNAME', 'repmgrd_is_paused'
LANGUAGE C STRICT;
CREATE VIEW repmgr.replication_status AS
SELECT m.primary_node_id, m.standby_node_id, n.node_name AS standby_name,
n.type AS node_type, n.active, last_monitor_time,
CASE WHEN n.type='standby' THEN m.last_wal_primary_location ELSE NULL END AS last_wal_primary_location,
m.last_wal_standby_location,
CASE WHEN n.type='standby' THEN pg_catalog.pg_size_pretty(m.replication_lag) ELSE NULL END AS replication_lag,
CASE WHEN n.type='standby' THEN
CASE WHEN replication_lag > 0 THEN age(now(), m.last_apply_time) ELSE '0'::INTERVAL END
ELSE NULL
END AS replication_time_lag,
CASE WHEN n.type='standby' THEN pg_catalog.pg_size_pretty(m.apply_lag) ELSE NULL END AS apply_lag,
AGE(NOW(), CASE WHEN pg_catalog.pg_is_in_recovery() THEN repmgr.standby_get_last_updated() ELSE m.last_monitor_time END) AS communication_time_lag
FROM repmgr.monitoring_history m
JOIN repmgr.nodes n ON m.standby_node_id = n.node_id
WHERE (m.standby_node_id, m.last_monitor_time) IN (
SELECT m1.standby_node_id, MAX(m1.last_monitor_time)
FROM repmgr.monitoring_history m1 GROUP BY 1
);