Hot and Cold Table Functions
pg_obs_cold_refresh_time(table_name, time)
Description: Modifies the time when cold data in a multi-temperature table is migrated to OBS. The default value is 00:00 every day.
table_name indicates the name of the multi-temperature table, and the type is Name. time indicates the time when the data switchover task is scheduled, and the type is Time.
Return value: SUCCESS. The time is successfully modified.
Example:
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SELECT * FROM pg_obs_cold_refresh_time('lifecycle_table', '06:30:00'); pg_obs_cold_refresh_time -------------------------- SUCCESS (1 row) |
pg_refresh_storage()
Description: Switches hot data to cold data on all hot and cold tables (in OBS).
Return type: int
Fields in the returned value
- success_count int: indicates the number of tables that are successfully switched.
- failed_count int: indicates the number of tables that fail to be switched.
Example:
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SELECT * FROM pg_refresh_storage(); success_count | failed_count ---------------+-------------- 1 | 0 (1 row) |
pg_lifecycle_table_data_distribute(table_name)
Description: Views the data distribution of a cold or hot table.
table_name indicates the table name and cannot be left blank.
Return value: record
Example: Multiple records are generated based on the number of nodes. The following example shows the data distribution in the w1 table when there is only one DN node.
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SELECT * FROM pg_catalog.pg_lifecycle_table_data_distribute('w1'); schemaname | tablename | nodename | hotpartition | coldpartition | switchablepartition | hotdatasize | colddatasize | switchabledatasize ------------+-----------+----------+--------------+---------------+---------------------+-------------+--------------+-------------------- public | w1 | dn_1 | p2 | p1 | | 80 KB | 0 bytes | 0 bytes (1 row) |
pg_lifecycle_node_data_distribute()
Description: Views the data distribution of all hot and cold tables.
Return value: record
Example: There are two cold and hot tables in the database. The data distribution is as follows:
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SELECT * FROM pg_catalog.pg_lifecycle_node_data_distribute(); schemaname | tablename | nodename | hotpartition | coldpartition | switchablepartition | hotdatasize | colddatasize | switchabledatasize ------------+-----------+----------+--------------+---------------+---------------------+-------------+--------------+-------------------- public | w1 | dn_1 | p2 | p1 | | 81920 | 0 | 0 public | w2 | dn_1 | p2 | p1 | | 81920 | 0 | 0 (2 rows) |
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