timescaledb/sql/cache.sql

-- This file contains infrastructure for cache invalidation of TimescaleDB
-- metadata caches kept in C. Please look at cache_invalidate.c for a
-- description of how this works.

CREATE TABLE  _timescaledb_cache.cache_inval_hypertable();
CREATE TABLE  _timescaledb_cache.cache_inval_chunk();

-- This is pretty subtle. We create this dummy cache_inval_extension table
-- solely for the purpose of getting a relcache invalidation event when it is
-- deleted on DROP extension. It has no related triggers. When the table is
-- invalidated, all backends will be notified and will know that they must
-- invalidate all cached information, including catalog table and index OIDs,
-- etc.  
--
-- The actual dropping of the extension is detected by
-- extension_event_trigger() below.  This table is used by
-- extension_event_trigger() to notify other backends.
CREATE TABLE  _timescaledb_cache.cache_inval_extension();

-- not actually strictly needed but good for sanity as all tables should be dumped.
SELECT pg_catalog.pg_extension_config_dump('_timescaledb_cache.cache_inval_hypertable', '');
SELECT pg_catalog.pg_extension_config_dump('_timescaledb_cache.cache_inval_chunk', '');
SELECT pg_catalog.pg_extension_config_dump('_timescaledb_cache.cache_inval_extension', '');

-- this trigger function causes an invalidation event on the table whose name is
-- passed in as the first element.
CREATE OR REPLACE FUNCTION _timescaledb_cache.invalidate_relcache_trigger()
 RETURNS TRIGGER AS '$libdir/timescaledb', 'invalidate_relcache_trigger' LANGUAGE C;

-- This function is only used for debugging
CREATE OR REPLACE FUNCTION _timescaledb_cache.invalidate_relcache(proxy_oid OID)
 RETURNS BOOLEAN AS '$libdir/timescaledb', 'invalidate_relcache' LANGUAGE C;

CREATE TRIGGER "0_cache_inval" AFTER INSERT OR UPDATE OR DELETE OR TRUNCATE ON _timescaledb_catalog.hypertable
FOR EACH STATEMENT EXECUTE PROCEDURE _timescaledb_cache.invalidate_relcache_trigger('cache_inval_hypertable');

CREATE TRIGGER "0_cache_inval" AFTER INSERT OR UPDATE OR DELETE OR TRUNCATE ON _timescaledb_catalog.partition_epoch
FOR EACH STATEMENT EXECUTE PROCEDURE _timescaledb_cache.invalidate_relcache_trigger('cache_inval_hypertable');

CREATE TRIGGER "0_cache_inval" AFTER INSERT OR UPDATE OR DELETE OR TRUNCATE ON _timescaledb_catalog.partition
FOR EACH STATEMENT EXECUTE PROCEDURE _timescaledb_cache.invalidate_relcache_trigger('cache_inval_hypertable');

CREATE TRIGGER "0_cache_inval" AFTER UPDATE OR DELETE OR TRUNCATE ON _timescaledb_catalog.chunk
FOR EACH STATEMENT EXECUTE PROCEDURE _timescaledb_cache.invalidate_relcache_trigger('cache_inval_chunk');

-- This function detects whether a CREATE EXTENSION or DROP EXTENSION is called
-- on this extension and takes the appropriate action.
CREATE OR REPLACE FUNCTION _timescaledb_cache.extension_event_trigger()
RETURNS EVENT_TRIGGER AS '$libdir/timescaledb', 'extension_event_trigger' LANGUAGE C;

CREATE EVENT TRIGGER "0_extension_create" ON ddl_command_end WHEN TAG IN ('CREATE EXTENSION')
EXECUTE PROCEDURE _timescaledb_cache.extension_event_trigger();

CREATE EVENT TRIGGER "0_extension_drop" ON ddl_command_start WHEN TAG IN ('DROP EXTENSION')
EXECUTE PROCEDURE _timescaledb_cache.extension_event_trigger();