Other Functions
pgxc_pool_check()
Description: Checks whether the connection data buffered in the pool is consistent with pgxc_node.
Return type: boolean
Example:
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SELECT pgxc_pool_check(); pgxc_pool_check ----------------- t (1 row) |
pgxc_pool_reload()
Description: Updates the connection information buffered in the pool.
Return type: boolean
Example:
1 2 3 4 5 |
SELECT pgxc_pool_reload(); pgxc_pool_reload ------------------ t (1 row) |
pg_pool_validate(clear boolean, co_node_name cstring)
Description: Clears invalid backend threads on a CN. (These backend threads hold invalid pooler connections to standby DNs.)
Return type: record
pg_nodes_memory()
Description: queries the memory usage of all nodes.
Return type: record
Example:
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SELECT * FROM pg_nodes_memory(); node_name | used_memory | shared_buffer_cache | top_context_memory ----------------------+-------------+------------------------------------+------------------------------ dn_6003_6004 | 353 MB | 108 MB(Utilization: 512 MB/21.00%) | PgStat BackendStatus(101 MB) | | | TopMemoryContext(59 MB) | | | gs_signal(56 MB) dn_6005_6006 | 353 MB | 202 MB(Utilization: 512 MB/39.00%) | PgStat BackendStatus(101 MB) | | | TopMemoryContext(59 MB) | | | gs_signal(56 MB) dn_6001_6002 | 351 MB | 201 MB(Utilization: 512 MB/39.00%) | PgStat BackendStatus(101 MB) | | | TopMemoryContext(58 MB) | | | gs_signal(56 MB) cn_5001 | 79 MB | 48 MB(Utilization: 256 MB/19.00%) | CacheMemoryContext(22 MB) | | | PgStat BackendStatus(19 MB) | | | gs_signal(16 MB) cn_5002 | 77 MB | 95 MB(Utilization: 256 MB/37.00%) | CacheMemoryContext(21 MB) | | | PgStat BackendStatus(19 MB) | | | gs_signal(16 MB) cn_5003 | 67 MB | 50 MB(Utilization: 256 MB/19.00%) | CacheMemoryContext(26 MB) | | | gs_signal(16 MB) | | | TopMemoryContext(9732 KB) (18 rows) |
plan_seed()
Description: Obtains the seed value of the previous query statement (internal use).
Return type: integer
Example:
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SELECT plan_seed(); plan_seed ----------- 0 (1 row) |
pg_stat_get_env()
Description: Obtains the environment variable information about the current node.
Return type: record
Example:
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SELECT * FROM pg_stat_get_env(); node_name | host | process | port | installpath | datapath | log_directory -----------+-----------+---------+------+------------------+------------------------+-------------------------------------- cn_5003 | localhost | 28811 | 8000 | /DWS/manager/app | /DWS/data1/coordinator | /DWS/manager/log/Ruby/pg_log/cn_5003 (1 row) |
pg_stat_get_thread()
Description: Provides information about the status of all threads under the current node.
Return type: record
Example:
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SELECT * FROM pg_stat_get_thread(); node_name | pid | lwpid | thread_name | creation_time -----------+-----------------+---------+--------------------+------------------------------- cn_5003 | 281471515199536 | 28930 | JobScheduler | 2023-01-04 07:03:16.086885+00 cn_5003 | 281471498418224 | 28931 | StatCollector | 2000-01-01 00:00:00+00 cn_5003 | 281471464855600 | 28933 | WDRSnapshot | 2023-01-04 07:03:16.086775+00 cn_5003 | 281471380949040 | 28938 | WorkloadMonitor | 2023-01-04 07:03:16.074454+00 cn_5003 | 281471414511664 | 28936 | workload | 2023-01-04 07:03:16.075457+00 cn_5003 | 281471364167728 | 28939 | WLMArbiter | 2023-01-04 07:03:16.076753+00 cn_5003 | 281471397730352 | 28937 | CalculateSpaceInfo | 2023-01-04 07:03:16.078981+00 cn_5003 | 281470777964592 | 1933534 | wlm | 2023-01-13 08:01:32.350808+00 cn_5003 | 281470889130032 | 1786064 | cn_5002 | 2023-01-13 07:01:50.173568+00 cn_5003 | 281471299672112 | 29006 | cm_agent | 2023-01-04 07:03:18.03415+00 cn_5003 | 281471222065200 | 29970 | cn_5002 | 2023-01-04 07:03:39.694702+00 cn_5003 | 281471238846512 | 1897367 | cn_5002 | 2023-01-04 20:01:40.611019+00 cn_5003 | 281470905911344 | 30053 | cn_5002 | 2023-01-04 07:03:44.065774+00 cn_5003 | 281470410537008 | 1933902 | cn_5002 | 2023-01-13 08:01:38.972574+00 cn_5003 | 281470872348720 | 1880248 | cn_5001 | 2023-01-13 07:39:24.231418+00 cn_5003 | 281471316453424 | 1883059 | cn_5001 | 2023-01-13 07:40:16.885667+00 cn_5003 | 281470845081648 | 1305053 | cn_5001 | 2023-01-13 03:40:17.366784+00 cn_5003 | 281470700357680 | 1500466 | wlm | 2023-01-13 05:02:05.714544+00 cn_5003 | 281470473455664 | 1883060 | cn_5001 | 2023-01-13 07:40:16.885963+00 cn_5003 | 281470717138992 | 32065 | cm_agent | 2023-01-04 07:04:23.906691+00 cn_5003 | 281470807328816 | 1977925 | gsql | 2023-01-13 08:20:04.509437+00 cn_5003 | 281470683576368 | 1835242 | cn_5001 | 2023-01-13 07:20:16.549546+00 cn_5003 | 281471584946224 | 28927 | Background writer | 2023-01-04 07:03:16.065631+00 cn_5003 | 281471633184816 | 28926 | CheckPointer | 2023-01-04 07:03:16.065872+00 cn_5003 | 281471548762160 | 28928 | Wal Writer | 2023-01-04 07:03:16.066366+00 cn_5003 | 281471448074288 | 28934 | TwoPhase Cleaner | 2023-01-04 07:03:16.071172+00 cn_5003 | 281471431292976 | 28935 | LWLock Monitor | 2023-01-04 07:03:16.072897+00 cn_5003 | 281470666795056 | 1210459 | CBM Writer | 2023-01-04 15:16:05.543143+00 (28 rows) |
pgxc_get_os_threads()
Description: Provides information about the status of threads under all normal nodes in a cluster.
Return type: record
pg_stat_get_sql_count()
Description: Provides statistics on the number of SELECT/UPDATE/INSERT/DELETE/MERGE INTO statements executed by all users on the current node, response time, and the number of DDL, DML, and DCL statements.
Return type: record
Example:
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SELECT * FROM pg_stat_get_sql_count(); node_name | user_name | select_count | update_count | insert_count | delete_count | mergeinto_count | ddl_count | dml_count | dcl_count | total_select_elapse | avg_select_elapse | max_select_el apse | min_select_elapse | total_update_elapse | avg_update_elapse | max_update_elapse | min_update_elapse | total_insert_elapse | avg_insert_elapse | max_insert_elapse | min_insert_elapse | total_delete_ela pse | avg_delete_elapse | max_delete_elapse | min_delete_elapse -----------+------------------------+--------------+--------------+--------------+--------------+-----------------+-----------+-----------+-----------+---------------------+-------------------+-------------- -----+-------------------+---------------------+-------------------+-------------------+-------------------+---------------------+-------------------+-------------------+-------------------+----------------- ----+-------------------+-------------------+------------------- cn_5003 | gs_role_read_all_stats | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 cn_5003 | gs_role_signal_backend | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 cn_5003 | gs_role_analyze_any | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 cn_5003 | gs_role_vacuum_any | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 cn_5003 | dbadmin | 641 | 0 | 3 | 0 | 0 | 18 | 651 | 5 | 19236129 | 30009 | 814 0206 | 357 | 0 | 0 | 0 | 0 | 70595 | 23531 | 62102 | 2750 | 0 | 0 | 0 | 0 cn_5003 | Ruby | 2078187 | 3263 | 22841 | 0 | 0 | 10436 | 2242517 | 16979 | 3753441293 | 1806 | 52 6891 | 191 | 67483165 | 20681 | 38076 | 15444 | 291598980 | 12766 | 35376 | 3791 | 0 | 0 | 0 | 0 cn_5003 | joe | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 cn_5003 | sea | 192 | 0 | 5 | 3 | 0 | 3 | 205 | 0 | 2561878 | 13343 | 68 1866 | 388 | 0 | 0 | 0 | 0 | 11349 | 2269 | 3241 | 1521 | 19 255 | 6418 | 10656 | 2798 cn_5003 | jj | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 cn_5003 | u1 | 2 | 0 | 2 | 0 | 0 | 1 | 4 | 0 | 3712 | 1856 | 2407 | 1305 | 0 | 0 | 0 | 0 | 5366 | 2683 | 3359 | 2007 | 0 | 0 | 0 | 0 (10 rows) |
pgxc_get_sql_count()
Description: Provides statistics on the number of SELECT/UPDATE/INSERT/DELETE/MERGE INTO statements executed by all users on all nodes of the current cluster, response time, and the number of DDL, DML, and DCL statements.
Return type: record
pgxc_get_workload_sql_count()
Description: Provides statistics on the number of SELECT/UPDATE/INSERT/DELETE statements executed in all workload Cgroup on all CNs of the current cluster and the number of DDL, DML, and DCL statements.
Return type: record
Example:
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SELECT * FROM pgxc_get_workload_sql_count(); node_name | workload | select_count | update_count | insert_count | delete_count | ddl_count | dml_count | dcl_count -----------+--------------+--------------+--------------+--------------+--------------+-----------+-----------+----------- cn_5003 | default_pool | 2079352 | 3264 | 22858 | 3 | 10460 | 2243738 | 16988 cn_5001 | default_pool | 2201345 | 9 | 0 | 0 | 10474 | 2359633 | 10465 cn_5002 | default_pool | 3784696 | 0 | 103106 | 136 | 10438 | 4039090 | 10498 (3 rows) |
pgxc_get_workload_sql_elapse_time()
Description: Provides statistics on response time of SELECT/UPDATE/INSERT/DELETE statements executed in all workload Cgroup on all CNs of the current cluster.
Return type: record
Example:
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SELECT * FROM pgxc_get_workload_sql_elapse_time(); node_name | workload | total_select_elapse | max_select_elapse | min_select_elapse | avg_select_elapse | total_update_elapse | max_update_elapse | min_update_elapse | avg_update_elapse | total_insert_el apse | max_insert_elapse | min_insert_elapse | avg_insert_elapse | total_delete_elapse | max_delete_elapse | min_delete_elapse | avg_delete_elapse -----------+--------------+---------------------+-------------------+-------------------+-------------------+---------------------+-------------------+-------------------+-------------------+---------------- -----+-------------------+-------------------+-------------------+---------------------+-------------------+-------------------+------------------- cn_5003 | default_pool | 3776420502 | 8140206 | 0 | 1816 | 67505332 | 38076 | 0 | 20682 | 29178 9830 | 62102 | 0 | 12765 | 19255 | 10656 | 0 | 6418 cn_5001 | default_pool | 8599339496 | 3390159 | 0 | 3906 | 52789 | 18207 | 0 | 5865 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 cn_5002 | default_pool | 40483096221 | 2178781 | 0 | 10695 | 0 | 0 | 0 | 0 | 13310238 8148 | 2398854 | 0 | 1290752 | 2072031 | 52877 | 0 | 15236 (3 rows) |
get_instr_unique_sql()
Description: Provides information about Unique SQL statistics collected on the current node. If the node is a CN, the system returns the complete information about the Unique SQL statistics collected on the CN. That is, the system collects and summarizes the information about the Unique SQL statistics on other CNs and DNs. If the node is a DN, the Unique SQL statistics on the DN is returned. For details, see the GS_INSTR_UNIQUE_SQL view.
Return type: record
reset_instr_unique_sql(cstring, cstring, INT8)
Description: Clears collected Unique SQL statistics. The input parameters are described as follows:
- GLOBAL/LOCAL: Data is cleared from all nodes or the current node.
- ALL/BY_USERID/BY_CNID/BY_GUC: ALL indicates that all data is cleared. BY_USERID/BY_CNID indicates that data is cleared by USERID or CNID. BY_GUC indicates that the clearance operation is caused by the decrease of the value of the GUC parameter instr_unique_sql_count.
- The third parameter corresponds to the second parameter. The parameter is invalid for ALL/BY_GUC.
Return type: bool
pgxc_get_instr_unique_sql()
Description: Provides complete information about Unique SQL statistics collected on all CNs in a cluster. This function can be executed only on CNs.
Return type: record
get_instr_unique_sql_remote_cns()
Description: Provides complete information about Unique SQL statements collected on all CNs in the cluster, except the CN on which the function is being executed. This function can be executed only on CNs.
Return type: record
pgxc_get_node_env()
Description: Provides the environment variable information about all nodes in a cluster.
Return type: record
Example:
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SELECT * FROM pgxc_get_node_env(); node_name | host | process | port | installpath | datapath | log_directory --------------+---------------+---------+-------+------------------+---------------------------+-------------------------------------- dn_6001_6002 | 172.16.102.5 | 24443 | 40000 | /DWS/manager/app | /DWS/data1/h0dn1/primary0 | /DWS/manager/log/Ruby/pg_log/dn_6001 dn_6003_6004 | 172.16.70.17 | 21823 | 40000 | /DWS/manager/app | /DWS/data1/h1dn1/primary0 | /DWS/manager/log/Ruby/pg_log/dn_6003 dn_6005_6006 | 172.16.120.50 | 22331 | 40000 | /DWS/manager/app | /DWS/data1/h2dn1/primary0 | /DWS/manager/log/Ruby/pg_log/dn_6005 cn_5003 | localhost | 28811 | 8000 | /DWS/manager/app | /DWS/data1/coordinator | /DWS/manager/log/Ruby/pg_log/cn_5003 cn_5001 | 172.16.102.5 | 30873 | 8000 | /DWS/manager/app | /DWS/data1/coordinator | /DWS/manager/log/Ruby/pg_log/cn_5001 cn_5002 | 172.16.70.17 | 29229 | 8000 | /DWS/manager/app | /DWS/data1/coordinator | /DWS/manager/log/Ruby/pg_log/cn_5002 (6 rows) |
pv_compute_pool_workload()
Description: Provides the current load information about computing Node Groups on cloud.
Return type: record
pg_stat_get_status(tid, num_node_display)
Description: Queries for the blocking and waiting status of the backend threads and auxiliary threads in the current instance. For details about the returned results, see the PG_THREAD_WAIT_STATUS view. The input parameters are described as follows:
- tid: thread ID, which is of the bigint type. If this parameter is null, the waiting statuses of all backend threads and auxiliary threads are returned. Otherwise, only the waiting statuses of threads with the specified IDs are returned.
- num_node_display: integer type. Specifies the maximum number of waiting nodes displayed in the wait_status column for records whose waiting status is wait node.
- If this parameter is left empty or set to a value less than or equal to 0, only one waiting node is displayed.
- If the value is greater than 20, a maximum number of nodes can be displayed is 20.
- If the value is greater than 0 and less than or equal to 20, the smaller value between num_node_display and the actual number of waiting nodes is displayed. Use the SELECT * from pg_stat_get_status(NULL, 10) query for example. If the number of waiting nodes is greater than 10, the names of only 10 nodes are displayed randomly. If the number of waiting nodes is less than or equal to 10, the names of all waiting nodes are displayed. If the number of waiting nodes is greater than the number of displayed nodes, the displayed node names are randomly selected.
Return type: record
pgxc_get_thread_wait_status(num_node_display)
Description: Queries for the call hierarchy between threads generated by all SQL statements on each node in a cluster, as well as the block waiting status of each thread. For details about the returned results, see the PGXC_THREAD_WAIT_STATUS view. The type and meaning of the input parameter num_node_display are the same as those of the pg_stat_get_status function.
Return type: record
pgxc_os_run_info()
Description: Obtains the running status of the operating system on each node in a cluster. For details about the returned results, see "System Catalogs > System Views >PV_OS_RUN_INFO" in the Developer Guide.
Return type: record
get_instr_wait_event()
Description: obtains the waiting status and events of the current instance. For details about the returned results, see "System Catalogs > System Views > GS_WAIT_EVENTS" in the Developer Guide. If the GUC parameter enable_track_wait_event is off, this function returns 0.
Return type: record
pgxc_wait_events()
Description: queries statistics about waiting status and events on each node in a cluster. For details about the returned results, see "System Catalogs > System Views > PGXC_WAIT_EVENTS" in the Developer Guide. If the GUC parameter enable_track_wait_event is off, this function returns 0.
Return type: record
pgxc_stat_bgwriter()
Description: queries statistics about backend write processes on each node in a cluster. For details about the returned results, see "System Catalogs > System Views > PG_STAT_BGWRITER" in the Developer Guide.
Return type: record
Example:
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SELECT * FROM pgxc_stat_bgwriter(); node_name | checkpoints_timed | checkpoints_req | checkpoint_write_time | checkpoint_sync_time | buffers_checkpoint | buffers_clean | maxwritten_clean | buffers_backend | buffers_backend_fsync | buffers_ alloc | stats_reset --------------+-------------------+-----------------+-----------------------+----------------------+--------------------+---------------+------------------+-----------------+-----------------------+--------- ------+------------------------ dn_6001_6002 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 2000-01-01 00:00:00+00 dn_6003_6004 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 2000-01-01 00:00:00+00 dn_6005_6006 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 2000-01-01 00:00:00+00 cn_5003 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 2000-01-01 00:00:00+00 cn_5001 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 2000-01-01 00:00:00+00 cn_5002 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 2000-01-01 00:00:00+00 (6 rows) |
pgxc_stat_replication()
Description: queries information about the log synchronization status on each node in a cluster, such as the location where the logs are sent and received. For details about the returned results, see "System Catalogs > System Views > PG_STAT_REPLICATION" in the Developer Guide.
Return type: record
Example:
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SELECT * FROM pgxc_stat_replication(); node_name | pid | usesysid | usename | application_name | client_addr | client_hostname | client_port | backend_start | state | sender_sent_location | receiver_wri te_location | receiver_flush_location | receiver_replay_location | sync_priority | sync_state --------------+-----------------+----------+---------+------------------------+---------------+-----------------+-------------+-------------------------------+-----------+----------------------+------------- ------------+-------------------------+--------------------------+---------------+------------ dn_6001_6002 | 281469637695536 | 10 | Ruby | WalSender to Standby | 172.16.70.17 | | 26084 | 2023-01-04 07:01:27.348647+00 | Streaming | 0/4940D6B8 | 0/4940D6B8 | 0/4940D6B8 | 0/4940D6B8 | 1 | Sync dn_6001_6002 | 281469304735792 | 10 | Ruby | WalSender to Secondary | 172.16.120.50 | | 35214 | 2023-01-04 07:01:29.51929+00 | Streaming | 0/4000000 | 0/4000000 | 0/4000000 | 0/4000000 | 0 | Sync dn_6003_6004 | 281469634050096 | 10 | Ruby | WalSender to Standby | 172.16.120.50 | | 13072 | 2023-01-04 07:01:26.28706+00 | Streaming | 0/493EF000 | 0/493EF000 | 0/493EF000 | 0/493EF000 | 1 | Sync dn_6003_6004 | 281469563295792 | 10 | Ruby | WalSender to Secondary | 172.16.102.5 | | 55068 | 2023-01-04 07:01:29.310595+00 | Streaming | 0/4000000 | 0/4000000 | 0/4000000 | 0/4000000 | 0 | Sync dn_6005_6006 | 281470349690928 | 10 | Ruby | WalSender to Standby | 172.16.102.5 | | 40376 | 2023-01-04 07:01:26.768434+00 | Streaming | 0/49415A70 | 0/49415A70 | 0/49415A70 | 0/49415A70 | 1 | Sync dn_6005_6006 | 281470010435632 | 10 | Ruby | WalSender to Secondary | 172.16.70.17 | | 33750 | 2023-01-04 07:01:29.499269+00 | Streaming | 0/4000000 | 0/4000000 | 0/4000000 | 0/4000000 | 0 | Sync (6 rows) |
pgxc_replication_slots()
Description: queries the replication status on each DN in a cluster. For details about the returned results, see "System Catalogs > System Views > PG_REPLICATION_SLOTS" in the Developer Guide.
Return type: record
Example:
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SELECT * FROM pgxc_replication_slots(); node_name | slot_name | plugin | slot_type | datoid | database | active | x_min | catalog_xmin | restart_lsn | dummy_standby --------------+-----------------+--------+-----------+--------+----------+--------+-------+--------------+-------------------+--------------- dn_6001_6002 | dn_6001_3002 | | physical | 0 | | t | | | | t dn_6001_6002 | dn_6001_6002 | | physical | 0 | | t | | | 0/49448720 | f dn_6001_6002 | gs_roach_common | | physical | 0 | | f | | 635143447 | FFFFFFFF/FFFFFFFF | f dn_6003_6004 | dn_6003_3003 | | physical | 0 | | t | | | | t dn_6003_6004 | dn_6003_6004 | | physical | 0 | | t | | | 0/4942B760 | f dn_6003_6004 | gs_roach_common | | physical | 0 | | f | | 634883623 | FFFFFFFF/FFFFFFFF | f dn_6005_6006 | dn_6005_3004 | | physical | 0 | | t | | | | t dn_6005_6006 | dn_6005_6006 | | physical | 0 | | t | | | 0/4944CE80 | f dn_6005_6006 | gs_roach_common | | physical | 0 | | f | | 635285455 | FFFFFFFF/FFFFFFFF | f (9 rows) |
pgxc_settings()
Description: queries information about runtime parameters on each node in a cluster. For details about the returned results, see "System Catalogs > System Views > PG_SETTINGS" in the Developer Guide.
Return type: record
pgxc_instance_time()
Description: queries the running time statistics of each node in a cluster and the time consumed in each execution phase. For details about the returned results, see "System Catalogs > System Views > PV_INSTANCE_TIME" in the Developer Guide.
Return type: record
pg_stat_get_redo_stat()
Description: queries Xlog redo statistics on the current node. For details about the returned results, see "System Catalogs > System Views > PV_REDO_STAT" in the Developer Guide.
Return type: record
Example:
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SELECT * FROM pg_stat_get_redo_stat(); phywrts | phyblkwrt | writetim | avgiotim | lstiotim | miniotim | maxiowtm ---------+-----------+----------+----------+----------+----------+---------- 400171 | 552783 | 11040710 | 27 | 20 | 8 | 7401 (1 row) |
pgxc_redo_stat()
Description: queries the Xlog redo statistics of each node in a cluster. For details about the returned results, see "System Catalogs > System Views > PV_REDO_STAT" in the Developer Guide.
Return type: record
Example:
SELECT * FROM pgxc_redo_stat(); node_name | phywrts | phyblkwrt | writetim | avgiotim | lstiotim | miniotim | maxiowtm --------------+---------+-----------+----------+----------+----------+----------+---------- dn_6001_6002 | 698244 | 836088 | 17608019 | 25 | 15 | 8 | 13115 dn_6003_6004 | 661128 | 799636 | 16714302 | 25 | 21 | 8 | 8195 dn_6005_6006 | 698146 | 836178 | 18117951 | 25 | 24 | 8 | 8326 cn_5003 | 400206 | 552823 | 11041701 | 27 | 18 | 8 | 7401 cn_5001 | 380931 | 514233 | 10174114 | 26 | 19 | 8 | 7726 cn_5002 | 551727 | 687991 | 11859292 | 21 | 31 | 8 | 10310 (6 rows)
get_local_rel_iostat()
Description: Obtains the disk I/O statistics of the current instance. For details about the returned results, see "System Catalogs > System Views > GS_REL_IOSTAT" in the Developer Guide.
Return type: record
pgxc_rel_iostat()
Description: queries the disk I/O statistics on each node in a cluster. For details about the returned result, see "System Catalogs > System Views > GS_REL_IOSTAT" in the Developer Guide.
Return type: record
get_node_stat_reset_time()
Description: Obtains the time when statistics of the current instance were reset.
Return type: timestamptz
pgxc_node_stat_reset_time()
Description: queries the time when the statistics of each node in a cluster are reset. For details about the returned result, see "System Catalogs > System Views > GS_NODE_STAT_RESET_TIME" in the Developer Guide.
Return type: record
- The instance is restarted or a cluster switchover occurs.
- The database is deleted.
- A reset operation is performed. For example, the statistics counter in the database is reset using the pgstat_recv_resetcounter function or the Unique SQL statements are cleared using the reset_instr_unique_sql function.
If any of the preceding events occurs, GaussDB(DWS) will record the time when the statistics are reset. You can query the time using the get_node_stat_reset_time function.
pgxc_parallel_query(text, text)
Description: Runs a specified SQL query statement on a data instance of a specified type and returns the query result to the current CN. This function is supported in 8.1.2 or later.
The function has two parameters:
The first parameter specifies the instances on which the SQL statement is executed. Currently, the valid input parameters are dn, datanode, cn, coordinator, and all. Other values will cause function execution errors. dn and datanode indicate that the statement is executed on all DNs. cn and coordinator indicate that the statement is executed on all CNs. all indicates that the statement is executed on all CNs and DNs.
The second parameter specifies the verification of the objects queried by the SQL statement that is to be sent to a remote node for execution. User tables, distributed tables, and user-defined functions with multiple result sets are not supported.
Return type: record
- This function is only used by developers to efficiently collect the execution information or status of instances in a cluster. You are not advised to use it directly.
- This function contains multiple result sets, and the return data type is record. Therefore, you need to add the output column name and data type specified by the AS statement after the function call, as shown in the following:
SELECT * FROM pgxc_parallel_query('all', 'select node_name, db_name, thread_name, query_id, tid, lwtid, ptid, tlevel, smpid, wait_status, wait_event from pg_thread_wait_status') AS (node_name text, db_name text, thread_name text, query_id bigint, tid bigint, lwtid integer , ptid integer, tlevel integer , smpid integer, wait_status text, wait_event text); - The data type of the output result of the SQL statement specified by the second parameter of the function must be the same as the data type specified by the AS statement. Otherwise, an error may be reported during execution due to type mismatch.
- The SQL statement specified by the second parameter of the function cannot trigger cross-node query. Otherwise, an error is reported.
- The SQL statement specified by the second parameter of the function can only be a SELECT, UPDATE, DELETE, or INSERT statement.
- The returning statement is not supported.
- The user who invokes the function must have the operation permission on the SQL objects.
- For INSERT statements, INSERT OVERWRITE, UPSERT, and INSERT INTO are not supported.
- The UPDATE, DELETE, and INSERT statements can be executed only by the initial user in in-place upgrade mode or by the administrator in redistribution mode. The number of records modified by the statements on each instance must be the same. Otherwise, an error will be reported during statement execution. The function outputs a column of values of the bigint type. These values indicate the number of records operated by the statement on each instance.
SELECT * FROM pgxc_parallel_query('cn', 'UPDATE pg_partition SET relpages = 0') AS (updated bigint);
generate_wdr_report(begin_snap_id bigint, end_snap_id bigint, report_type cstring, report_scope cstring, node_name cstring)
Description: Creates a load analysis report. The input parameters are described as follows:
- begin_snap_id and end_snap_id: IDs of the start and end snapshots, respectively. The IDs are of the bigint type. The value of begin_snap_id must be less than that of end_snap_id, and the time for the start and end snapshots cannot overlap. You can check whether the snapshot time overlaps by querying select s1.end_ts < s2.start_ts from (select * from dbms_om.snapshot where snapshot_id=$begin_snap_id) as s1, (select * from dbms_om.snapshot where snapshot_id=$end_snap_id) as s2 in the dbms_om.snapshot table. If true is returned, the snapshot time does not overlap. Otherwise, the snapshot time overlaps.
- report_type: report type. The value is a cstring and can be summary, detail, or all.
- report_scope: report scope. The value is a cstring and can be cluster or node.
- node_name: node name. The value is a cstring. If report_scope is node, the value of this parameter must be pg_catalog, which indicates the CN or DN name in the node_name column of the pgxc_node table.
- Only the database administrator SYSADMIN can execute this function.
- This function can be executed only on CNs. If it is executed on DNs, the following message will be returned: "WDR report can only be created on coordinator."
- If the report is created successfully, message "Report %s has been generated" will be returned.
- The statistics cannot be reset between the time the start snapshot is taken and the time the end snapshot is taken. Otherwise, error message "Instance reset time is different" will be displayed. For details about the events that cause a statistics reset, see the pgxc_node_stat_reset_time function.
wdr_xdb_query(db_name text, snapshot_id bigint, view_name text)
Description: Queries a specified view in a specified database. The query results of some views vary depending on databases. For example, the global_table_stat view is used to query the statistics of a table. The results of querying this view vary because tables in different databases are different. The wdr_xdb_query function can access the database specified by db_name in the current connection and query the view specified by view_name in the database. The input parameters are described as follows:
- db_name: specifies the name of a database. The value is of the text type.
- snapshot_id: specifies the snapshot ID. The value is of the bigint type. For details, see "Performance View Snapshot".
- view_name: specifies the name of a view. The value is of the text type. The view name must be in the following whitelist:
- global_table_stat
- global_table_change_stat
- global_column_table_io_stat
- global_row_table_io_stat
The return value type is record. The first column is snapshot_id bigint, and the second column is db_name text. The names, types, and sequences of other columns are the same as those of the views specified by view_name.
Example:
1 2
SELECT snapshot_id, db_name, schemaname, relname, distribute_mode, seq_scan ,seq_tuple_read ,index_scan ,index_tuple_read ,tuple_inserted ,tuple_updated ,tuple_deleted ,tuple_hot_updated ,live_tuples ,dead_tuples from wdr_xdb_query('postgres'::text, 1, 'global_table_stat'::text) as i(snapshot_id bigint, db_name text, schemaname name, relname name, distribute_mode char, seq_scan bigint, seq_tuple_read bigint, index_scan bigint, index_tuple_read bigint, tuple_inserted bigint, tuple_updated bigint, tuplee_deleted bigint, tuple_hot_updated bigint, live_tuples bigint, dead_tuples bigint);
- This function is supported only in 8.1.2 or later.
- Only the database administrator SYSADMIN can execute this function.
- This function can be used to query only the views in the whitelist. If you use this function to query other views, the error message Input view name is invalid. will be displayed.
vac_fileclear_relation(oid)
Description: Forcibly clears VACUUM rewritten files in a specified column-store table to reclaim space.
Parameter: OID of a column-store table.
Return type: integer
- Before using this function, set colvacuum_threshold_scale_factor and ensure that the files are cleared and space reclaimed only after the VACUUM process has rewritten the files of the specified column-store table.
- This function exclusively locks a specified column-store table.
vac_fileclear_all_relation()
Description: Forcibly clears VACUUM rewritten files in all specified column-store tables to reclaim space.
Return type: record
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