Global SysCache Functions
- gs_gsc_table_detail(database_id default NULL, rel_id default NULL)
Description: Queries the table metadata in the global system cache in a database. The user who calls this function must have the SYSADMIN permission.
Parameter: Specifies the database and table whose global system cache is to be queried. The default value of database_id is NULL or –1, indicating all databases. The value 0 indicates a shared table. Other values indicate the specified database and shared table. rel_id indicates the OID of the specified table. The default value NULL or –1 indicates all tables. Other values indicate the specified table. If the table does not exist, an error is reported. If the OID does not exist, a null result is returned.
Return type: Tuple
Example:
select * from gs_gsc_table_detail(-1) limit 1; database_oid | database_name | reloid | relname | relnamespace | reltype | reloftype | relowner | relam | relfilenode | reltablespace | relhasindex | relisshared | relkind | relnatts | relhasoids | relhaspkey | parttype | tdhasuids | attnames | extinfo --------------+---------------+--------+-------------------------+--------------+---------+-----------+----------+-------+-------------+---------------+-------------+-------------+---------+----------+------------+------------+----------+-----------+-----------+--------- 0 | | 2676 | pg_authid_rolname_index | 11 | 0 | 0 | 10 | 403 | 0 | 1664 | f | t | i | 1 | f | f | n | f | 'rolname' | (1 row)
- gs_gsc_catalog_detail(database_id default NULL, rel_id default NULL)
Description: Queries the system catalog row information in the global system cache in a database. The user who calls this function must have the SYSADMIN permission.
Parameter: Specifies the database and table whose global system cache is to be queried. The default value of database_id is NULL or –1, indicating all databases. The value 0 indicates a shared table. Other values indicate the specified database and shared table. rel_id indicates the ID of the specified table, including all system catalogs that have system caches. The default value NULL or –1 indicates all tables. Other values indicate the specified table. If the database does not exist, an error is reported. If the table does not exist, a null result is returned.
Return type: Tuple
Example:
-- Obtain the OID of a specific database through pg_database, for example, running SELECT oid, * FROM pg_database;. -- In the returned tuple, find the value of the OID column based on the database name column, and then run the following query command. In the example, the obtained OID is 16574. gaussdb=# select * from gs_gsc_catalog_detail(16574, 1260); database_id | database_name | rel_id | rel_name | cache_id | self | ctid | infomask | infomask2 | hash_value | refcount -------------+---------------+--------+-----------+----------+--------+--------+----------+-----------+------------+---------- 0 | | 1260 | pg_authid | 10 | (0, 9) | (0, 9) | 10507 | 26 | 531311568 | 10 0 | | 1260 | pg_authid | 11 | (0, 4) | (0, 4) | 2313 | 26 | 365368336 | 1 0 | | 1260 | pg_authid | 11 | (0, 9) | (0, 9) | 10507 | 26 | 3911517328 | 10 0 | | 1260 | pg_authid | 11 | (0, 7) | (0, 7) | 2313 | 26 | 1317799983 | 1 0 | | 1260 | pg_authid | 11 | (0, 5) | (0, 5) | 2313 | 26 | 3664347448 | 1 0 | | 1260 | pg_authid | 11 | (0, 1) | (0, 1) | 2313 | 26 | 276477273 | 1 0 | | 1260 | pg_authid | 11 | (0, 3) | (0, 3) | 2313 | 26 | 2465837659 | 1 0 | | 1260 | pg_authid | 11 | (0, 8) | (0, 8) | 2313 | 26 | 3205288035 | 1 0 | | 1260 | pg_authid | 11 | (0, 6) | (0, 6) | 2313 | 26 | 131811687 | 1 0 | | 1260 | pg_authid | 11 | (0, 2) | (0, 2) | 2313 | 26 | 1226484587 | 1 (10 rows)
- gs_gsc_clean(database_id default NULL)
Description: Clears the global system cache. Note that data in use will not be cleared. The user who calls this function must have the SYSADMIN permission.
Parameter: Specifies the database whose global system cache needs to be cleared. The default value NULL or value –1 indicates that the global system cache of all databases is forcibly cleared. The value 0 indicates that the global system cache of only the shared table is cleared. Other values indicate that the global system cache of a specified database and a specified shared table is cleared. If database_id does not exist, an error is reported.
Return type: Boolean
Example:
gaussdb=# select * from gs_gsc_clean(); gs_gsc_clean -------------- t (1 row)
- gs_gsc_dbstat_info(database_id default NULL)
Description: Obtains GSC memory statistics on the local node, including cache query, hit, loading, expiration, and occupied space information of tuples, relations, and partitions, database-level eviction information, thread reference information, and memory usage information. This parameter can be used to locate performance problems. For example, if the value of the hits or searches array is far less than 1, the value of global_syscache_threshold may be too small. As a result, the query hit ratio decreases. The user who calls this function must have the SYSADMIN permission.
Parameter: Specifies the global system cache statistics of the database to be queried. Value NULL or –1 indicates that all databases are queried. Value 0 indicates that only the shared table is queried. Other values indicate that a specified database and a specified shared table are queried. If an invalid value is entered, an error is reported, indicating that database_id does not exist.
Return type: Tuple
Example:
gaussdb=# select * from gs_gsc_dbstat_info(); database_id | database_name | tup_searches | tup_hits | tup_miss | tup_count | tup_dead | tup_memory | rel_searches | rel_hits | rel_mis s | rel_count | rel_dead | rel_memory | part_searches | part_hits | part_miss | part_count | part_dead | part_memory | total_memory | swa pout_count | refcount -------------+---------------+--------------+----------+----------+-----------+----------+------------+--------------+----------+-------- --+-----------+----------+------------+---------------+-----------+-----------+------------+-----------+-------------+--------------+---- -----------+---------- 0 | | 300 | 235 | 31 | 22 | 2 | 9752 | 598 | 108 | 1 8 | 18 | 0 | 77720 | 0 | 0 | 0 | 0 | 0 | 0 | 752912 | 0 | 0 16574 | testdb | 3368 | 2289 | 329 | 273 | 0 | 92593 | 1113 | 524 | 4 8 | 48 | 0 | 340456 | 0 | 0 | 0 | 0 | 0 | 0 | 4124792 | 0 | 10 (2 rows)
Feedback
Was this page helpful?
Provide feedbackThank you very much for your feedback. We will continue working to improve the documentation.See the reply and handling status in My Cloud VOC.
For any further questions, feel free to contact us through the chatbot.
Chatbot
