Other Functions
pgxc_pool_check()
Description: Checks whether the connection data buffered in the pool is consistent with pgxc_node.
Return type: Boolean
pgxc_pool_reload()
Description: Updates the connection information buffered in the pool.
Return type: Boolean
reload_active_coordinator()
Description: Updates the connection information buffered in the pool for all active CNs.
Return type: void
pgxc_lock_for_backup()
Description: Locks a cluster for taking backup that would be restored on the new node to be added.
Return type: Boolean

pgxc_lock_for_backup locks a cluster before gs_dump or gs_dumpall is used to back up the cluster. After a cluster is locked, operations changing the system structure are not allowed. This function does not affect DML statements.
pg_pool_validate(clear bool, node_name text)
Description: Displays invalid connections in the pooler between the CN and node_name. When the value of clear is true, invalid connections are cleared.
Return type: record
gs_validate_node_conn(validate_type cstring, validate_node_name cstring)
Description: Displays or clears the connections received by the current node from a specified node.
Return type: record
Category |
Parameter |
Type |
Description |
---|---|---|---|
Input parameter |
validate_type |
cstring |
Specifies an input parameter type.
|
Input parameter |
validate_node_name |
cstring |
Specifies a node name. |
Output parameter |
pid |
bigint |
Displays the ID of a thread where the current node receives connections from the specified node. If the thread is from a thread pool, the value is 0. |
Output parameter |
sessionid |
bigint |
Displays the ID of a session where the current node receives connections from the specified node. If the thread is not from a thread pool, the value is 0. |
Output parameter |
node_name |
text |
Displays the name of a node from which the current node receives connections. |
pgxc_pool_connection_status()
Description: Checks whether the pooler connection status is normal.
Return type: Boolean
pg_nodes_memory()
Description: Queries the memory usage of all nodes.
Return type: record
table_skewness(text)
Description: Queries the percentage of table data among all nodes.
Parameter: Indicates that the type of the name of the to-be-queried table is text.
Return type: record
table_skewness(text, text, text)
Description: Queries the percentage of a specified column in the table data among all nodes.
Parameters: name of the table to be queried, specified column name, and number of records in the specified table. The default value is 0, indicating that all records are queried. All parameters are of the text type.
Return type: record
Return value description: Node ID, number of data rows in a specified column, and percentage of the data volume of the current node to the total data volume
Example:
-- Return the distribution of the first five rows of data in the a column of the t table on a node. gaussdb=# SELECT table_skewness('t', 'a',5); table_skewness ---------------- (1,3,60.000%) (2,2,40.000%) (2 rows) -- Return the distribution of all data in the a column of the t table on a node. gaussdb=# SELECT table_skewness('t', 'a'); table_skewness ---------------- (1,7,70.000%) (2,2,20.000%) (0,1,10.000%) (3 rows)
table_skewness_with_schema(text, text)
Description: Checks the proportion of table data on all nodes. The function is the same as that of table_skewness(text).
text indicates that the types of the schema name and table name for the table to be queried are both text.
Return type: record
table_data_skewness(colrecord, type)
Description: Queries the node where the table data is located.
Parameter description:
colrecord: column name record of the table to be queried. The value is of the record type.
type: hash distribution type.
Return type: smallint
Example:
-- Return the node where the index column data of the 'test1' table is located.
gaussdb=# SELECT table_data_skewness(row(index), 'R') FROM test1;
table_data_skewness
---------------------
4
3
1
2
(4 rows)
table_distribution(schemaname text, tablename text)
Description: Queries the storage space occupied by a specified table on each node.
text indicates that the types of the schema name and table name for the table to be queried are both text.
Return type: record

- To query the storage distribution of a specified table by using this function, you must have the SELECT permission for the table.
- The performance of table_distribution is better than that of table_skewness. Especially, in scenarios with a large amount of data, table_distribution is recommended.
- When you use table_distribution and want to view the space usage, you can use dnsize or (sum(dnsize) over ()) to view the percentage.
table_distribution()
Description: Queries the storage distribution of all tables in the current database.
Return type: record

- This function involves the query for information about all tables in the database. To execute this function, you must have the administrator rights.
- Based on the table_distribution() function, GaussDB provides the PGXC_GET_TABLE_SKEWNESS view as an alternative way to query data skew. You are advised to use this view when the number of tables in the database is less than 10000.
plan_seed()
Description: Obtains the seed value of the previous query statement (internal use).
Return type: int
pg_stat_get_env()
Description: Obtains the environment variable information of the current node. Only users with the SYSADMIN or MONADMIN permission can access the environment variable information.
Return type: record
Example:
gaussdb=# SELECT pg_stat_get_env();
pg_stat_get_env
---------------------------------------------------------------------------------------------------------------------------------------
(coordinator1,localhost,144773,49100,/data1/GaussDB_Kernel_TRUNK/install,/data1/GaussDB_Kernel_TRUNK/install/data/coordinator1,gs_log)
(1 row)
pg_catalog.plancache_clean()
Description: Clears the global plan cache that is not used on the current node.
Return type: Boolean
pg_stat_get_thread()
Description: Provides thread status information on the current node. Users with the SYSADMIN or MONADMIN permission can view information about all threads. Common users can view only their own thread information.
Return type: record
pgxc_get_os_threads()
Description: Provides thread status information about all normal nodes in the entire cluster.
Return type: record
pg_stat_get_sql_count()
Description: Provides the counts of the SELECT, UPDATE, INSERT, DELETE, and MERGE INTO statements executed by all users on the current node, as well as the counts of DDL, DML, and DCL statements. The DDL statements include TRUNCATE, VACUUM, ANALYZE, CREATE (excluding CREATE ROLE and CREATE USER), DROP (excluding DROP ROLE and DROP USER), ALTER (excluding ALTER ROLE, ALTER USER, and ALTER DEFAULT PRIVILEGES), REINDEX, and COMMENT statements. The DML statements include the UPDATE, INSERT, DELETE, MERGE, PREPARE, EXPLAIN, SHOW, LOCK, COPY, CLUSTER, ANONYMOUS, DELTA, EXECUTE, MOVE, FETCH, CLOSE, DEALLOCATE, DECLARE, and LOAD statements. The DCL statements include the CREATE ROLE, CREATE USER, DROP ROLE, DROP USER, ALTER ROLE, ALTER USER, ALTER DEFAULT PRIVILEGES, GRANT, REVOKE, REASSIGN, and SET statements. Users with the SYSADMIN or MONADMIN permission can view information about all users. Common users can view only their own statistics.
Return type: record
pgxc_get_sql_count()
Description: Provides the counts of the SELECT, UPDATE, INSERT, DELETE, and MERGE INTO statements executed by all users on all nodes in the entire cluster, as well as the counts of DDL, DML, and DCL statements. The DDL statements include TRUNCATE, VACUUM, ANALYZE, CREATE (excluding CREATE ROLE and CREATE USER), DROP (excluding DROP ROLE and DROP USER), ALTER (excluding ALTER ROLE, ALTER USER, and ALTER DEFAULT PRIVILEGES), REINDEX, and COMMENT statements. The DML statements include the UPDATE, INSERT, DELETE, MERGE, PREPARE, EXPLAIN, SHOW, LOCK, COPY, CLUSTER, ANONYMOUS, DELTA, EXECUTE, MOVE, FETCH, CLOSE, DEALLOCATE, DECLARE, and LOAD statements. The DCL statements include the CREATE ROLE, CREATE USER, DROP ROLE, DROP USER, ALTER ROLE, ALTER USER, ALTER DEFAULT PRIVILEGES, GRANT, REVOKE, REASSIGN, and SET statements.
Return type: record
pgxc_get_node_env()
Description: Provides the environment variable information about all nodes in a cluster.
Return type: record
pgxc_disaster_read_set(text)
Description: Configures node information about the standby cluster for DR on ETCD. Only the standby cluster for DR is available and can be called only by the initial user.
Return type: Boolean
pgxc_disaster_read_init()
Description: Initializes readable DR resources and status information. Only the standby cluster for DR is available and can be called only by the initial user.
Return type: Boolean
pgxc_disaster_read_clear()
Description: Clears readable DR resources and status information. Only the standby cluster for DR is available and can be called only by the initial user.
Return type: Boolean
pgxc_disaster_read_status()
Description: Provides node information about the standby cluster for DR. This function is available only for the standby cluster for DR.
Return type: record
gs_switch_relfilenode()
Description: Exchanges meta information of two tables or partitions. (This is only used for the redistribution tool. An error message is displayed when the function is directly used by users).
Return type: int

This function may cause clearing of statistics. You are advised to collect statistics again after this function is called.
DBE_PERF.global_plancache_clean()
Description: Clears the global plan cache that is not used on all nodes.
Return type: Boolean
copy_error_log_create()
Description: The error table required by the COPY FROM error tolerance mechanism has been changed to the system catalog created during initialization. Therefore, the current function always returns true for compatibility.
Return type: Boolean
Column |
Type |
Description |
---|---|---|
relname |
character varying |
Table name, in the form of Schema name.Table name. |
begintime |
timestamp with time zone |
Time when a data format error was reported. |
filename |
character varying |
Name of the source data file where a data format error occurs. |
lineno |
bigint |
Number of the row where a data format error occurs in a source data file. |
rawrecord |
text |
Raw record of a data format error in the source data file. |
detail |
text |
Error details. |
pg_stat_get_data_senders()
Description: Provides detailed information about the data-copy sender thread active at the moment.
Return type: record
textlen()
Description: Provides the method of querying the logical length of text.
Return type: int
threadpool_status()
Description: Displays the status of worker threads and sessions in the thread pool.
Return type: record
get_local_active_session()
Description: Provides sampling records of historical active sessions stored in the memory by current node. Users with the SYSADMIN or MONADMIN permission can view all historical active session records of the current node. Common users can view the historical active session records of the current session.
Return type: record
dbe_perf.get_global_active_session()
Description: Provides sampling records of the historical active sessions stored in the memory of all CNs and primary DNs. The event_start_time, current_xid, and top_xid columns are added to GaussDB Kernel 505.0. After GaussDB Kernel is upgraded to GaussDB Kernel 505.0 or later, the columns cannot be queried during the upgrade observation period.
Return type: record
dbe_perf.get_global_gs_asp(timestamp,timestamp)
Description: Provides sampling records of the historical active sessions stored in the gs_asp system catalog of all nodes. The event_start_time, current_xid, and top_xid columns are added to GaussDB Kernel 505.0. After GaussDB Kernel is upgraded to GaussDB Kernel 505.0 or later, the columns cannot be queried during the upgrade observation period.
Return type: record
get_wait_event_info()
Description: Provides detailed information about the wait event.
Return type: record
dbe_perf.get_datanode_active_session(text)
Description: Provides sampling records of historical active sessions stored in the memory of primary DN, which is queried from CN. The event_start_time, current_xid, and top_xid columns are added to GaussDB Kernel 505.0. After GaussDB Kernel is upgraded to GaussDB Kernel 505.0 or later, the columns cannot be queried during the upgrade observation period.
Return type: record
Note: This function queries the records in the LOCAL_ACTIVE_SESSION view on the target DN and matches the records with those in the LOCAL_ACTIVE_SESSION view on all CNs to obtain the query string. Therefore, a large amount of memory is occupied.
dbe_perf.get_datanode_active_session_hist(text,timestamp,timestamp)
Description: Provides sampling records of historical active sessions stored in the gs_asp system catalog of primary DN, which is queried from CN. The event_start_time, current_xid, and top_xid columns are added to GaussDB Kernel 505.0. After GaussDB Kernel is upgraded to GaussDB Kernel 505.0 or later, the columns cannot be queried during the upgrade observation period.
Return type: record
Note: This function queries the gs_asp records of a specified period on the target DN. If the period is specified too long, too many records will be queried, which takes a long time.
generate_wdr_report(begin_snap_id bigint, end_snap_id bigint, report_type cstring, report_scope cstring, node_name cstring)
Description: Generates a system diagnosis report based on two snapshots. By default, the initial user or MONADMIN can access the report. The result can be queried only in the system database but cannot be queried in the user database.
Return type: text
Parameter |
Description |
Value Range |
---|---|---|
begin_snap_id |
Snapshot ID that starts the diagnosis report period. |
N/A |
end_snap_id |
Snapshot ID that ends the diagnosis report period. By default, the value of end_snap_id is greater than that of begin_snap_id. |
N/A |
report_type |
Specifies the type of the generated report. |
|
report_scope |
Specifies the scope of the generated report. |
|
node_name |
|
|
generate_wdr_db_report(db_name cstring, begin_snap_id bigint, end_snap_id bigint, report_type cstring, report_scope cstring, node_name cstring)
Description: Generates database-level system diagnosis reports based on two snapshots. You need to run the command in the system database. By default, the initial user or users with the MONADMIN permission can access the database. The result can be queried only in the system database but cannot be queried in the user database.
Return type: record
Parameter |
Description |
Value Range |
---|---|---|
db_name |
Specifies the name of a database. |
N/A |
begin_snap_id |
Snapshot ID that starts the diagnosis report period. |
N/A |
end_snap_id |
Snapshot ID that ends the diagnosis report period. By default, the value of end_snap_id is greater than that of begin_snap_id. |
N/A |
report_type |
Specifies the type of the generated report. |
|
report_scope |
Specifies the scope of the generated report. |
|
node_name |
|
|
create_wdr_snapshot()
Description: Manually generates system diagnosis snapshots. This function requires the SYSADMIN permission and can be executed only on the CCN.
Return type: text
kill_snapshot()
Description: Kills the WDR snapshot backend thread. Users who call this function must have the SYSADMIN permission or the REPLICATION permission, or inherit permissions of the built-in role gs_role_replication.
Return type: void
dbe_perf.get_active_session_profile(start_ts timestamp with time zone, end_ts timestamp with time zone, need_final boolean,node_name text)
Description: Queries data in the ASP memory and disk based on timestamps. need_final specifies whether to query blocking information. The default value is false. node_name is used to distinguish the CN, active and standby DNs, for example, cn_5001, dn_6001 or dn_6002. This parameter cannot be left empty. The event_start_time, current_xid, and top_xid columns are added to GaussDB Kernel 505.0. After GaussDB Kernel is upgraded to GaussDB Kernel 505.0 or later, the columns cannot be queried during the upgrade observation period.
Return type: record
capture_view_to_json(text,integer)
Description: Saves the view result to the directory specified by GUC: perf_directory. If is_crossdb is set to 1, the view is accessed once for all databases. If the value of is_crossdb is 0, the current database is accessed only once. Only users with the SYSADMIN or MONADMIN permission can execute this function.
Return type: int
reset_unique_sql(text,text,bigint)
Description: Clears the unique SQL statements in the memory of CN/DN. (The SYSADMIN or MONADMIN permission is required.)
Return type: Boolean
Parameter |
Type |
Description |
---|---|---|
scope |
text |
Clearance scope type. The options are as follows: 'GLOBAL': Clears all CNs/DNs. If the value is 'GLOBAL', this function can be executed only on the CN. 'LOCAL': Clears the current node. |
clean_type |
text |
'BY_USERID': Unique SQL statements are cleared based on user IDs. 'BY_CNID': Unique SQL statements are cleared based on CN IDs. 'ALL': All data is cleared. |
clean_value |
int8 |
Clearance value corresponding to the clearance type. If the second parameter is set to ALL, the third parameter does not take effect and can be set to any value. |
wdr_xdb_query(db_name_str text, query text)
Description: Provides the capability of executing local cross-database queries. For example, when logging to the testdb database, access tables in the test database. Only the initial user has the permission to run this command.
SELECT col1 from wdr_xdb_query('dbname=test','select col1 from t1') as dd(col1 int);
Return type: record
pg_wlm_jump_queue(pid int)
Description: Moves a task to the top of the queue of CN.
Return type: Boolean
- true: success
- false: failure
gs_wlm_switch_cgroup(pid int, cgroup text)
Description: Moves a job to another Cgroup to change the job priority.
Return type: Boolean
- true: success
- false: failure
pv_session_memctx_detail(threadid tid, MemoryContextName text)
Description: Records information about the memory context MemoryContextName of the thread tid into the threadid_timestamp.log file in the $GAUSSLOG/gs_log/${node_name}/dumpmem directory. threadid can be obtained from sessid in the PV_SESSION_MEMORY_DETAIL table. In the officially released version, only the MemoryContextName that is an empty string (two single quotation marks indicate that the input is an empty string) is accepted. In this case, all memory context information is recorded. Otherwise, no operation is performed. This function can be executed only by the administrator.
Return type: Boolean
- true: success
- false: failure
pg_shared_memctx_detail(MemoryContextName text)
Description: Records information about the memory context MemoryContextName into the threadid_timestamp.log file in the $GAUSSLOG/gs_log/${node_name}/dumpmem directory. Calling this function in the officially released version does not involve any operation. Only the administrator can execute this function.
Return type: Boolean
- true: success
- false: failure
local_aio_completer_stat()
Description: Displays statistics about the AIO Completer thread in the instance.
Return type: record
Parameter |
Type |
Description |
---|---|---|
node_name |
text |
Name of the current instance. |
tid |
int8 |
ID of the AIO Completer thread. |
thread_type |
text |
AIO Completer thread type (read or write). |
aio_submitted_num |
int8 |
Number of committed asynchronous I/O requests of the AIO Completer thread. |
aio_completed_num |
int8 |
Number of completed asynchronous I/O requests of the AIO Completer thread. |
aio_incompleted_num |
int8 |
Number of asynchronous I/O requests that are not completed of the AIO Completer thread. |
slot_count_left |
int8 |
Indicates the number of idle slots. |
local_aio_slot_usage_status()
Description: Displays statistics about asynchronous I/O commit slots in the instance.
Return type: record
Parameter |
Type |
Description |
---|---|---|
node_name |
text |
Name of the current instance. |
slot_id |
int4 |
Slot ID. |
slot_type |
char |
Slot type. The value can be r (read) or w (write). |
status |
bool |
Slot usage status. |
buffer_id |
int8 |
Buffer ID corresponding to the slot. |
relfilenode_blocknum |
text |
Position of the physical page where the buffer corresponding to the slot is located. |
lsn |
int8 |
LSN corresponding to the page. |
submitted_time |
int8 |
Time when a page is committed asynchronously. |
elapsed_time |
int8 |
Waiting time of the page. |
remote_aio_completer_stat()
Description: Displays statistics about the AIO Completer thread in other instances (used only on CNs).
Return type: record
Parameter |
Type |
Description |
---|---|---|
node_name |
text |
Name of another instance. |
tid |
int8 |
ID of the AIO Completer thread. |
thread_type |
text |
AIO Completer thread type (read or write). |
aio_submitted_num |
int8 |
Number of committed asynchronous I/O requests of the AIO Completer thread. |
aio_completed_num |
int8 |
Number of completed asynchronous I/O requests of the AIO Completer thread. |
aio_incompleted_num |
int8 |
Number of asynchronous I/O requests that are not completed of the AIO Completer thread. |
slot_count_left |
int8 |
Indicates the number of idle slots. |
remote_aio_slot_usage_status()
Description: Displays statistics about asynchronous I/O commit slots in other instances.
Return type: record
Parameter |
Type |
Description |
---|---|---|
node_name |
text |
Name of another instance. |
slot_id |
int4 |
Slot ID. |
slot_type |
char |
Slot type. The value can be r (read) or w (write). |
status |
bool |
Slot usage status. |
buffer_id |
int8 |
Buffer ID corresponding to the slot. |
relfilenode_blocknum |
text |
Position of the physical page where the buffer corresponding to the slot is located. |
lsn |
int8 |
LSN corresponding to the page. |
submitted_time |
int8 |
Time when a page is committed asynchronously. |
elapsed_time |
int8 |
Waiting time of the page. |
gs_get_io_type()
Description: Displays the I/O mode of the instance.
Return type: text
- BIO: The instance is running in BIO mode (ADIO is disabled).
- DIO: The instance is running in DIO mode (ADIO is enabled).
- BIO->DIO (In progress): The current instance is switching from the BIO mode to the DIO mode.
local_bgwriter_stat()
Description: Displays the information about pages flushed by the bgwriter thread of this instance, number of pages in the candidate buffer chain, and buffer elimination information.
Return type: record
local_candidate_stat()
Description: Displays the number of pages in the candidate buffer chain of this instance and buffer elimination information, including the normal buffer pool and segment buffer pool.
Return type: record
local_ckpt_stat()
Description: Displays the information about checkpoints and flushing pages of the current instance.
Return type: record
local_double_write_stat()
Description: Displays the doublewrite file status of the current instance.
Parameter |
Type |
Description |
---|---|---|
node_name |
text |
Instance name |
curr_dwn |
int8 |
Sequence number of the doublewrite file |
curr_start_page |
int8 |
Start page for restoring the doublewrite file |
file_trunc_num |
int8 |
Number of times that the doublewrite file is reused |
file_reset_num |
int8 |
Number of reset times after the doublewrite file is full |
total_writes |
int8 |
Total number of I/Os of the doublewrite file |
low_threshold_writes |
int8 |
Number of I/Os for writing doublewrite files with low efficiency (the number of I/O flushing pages at a time is less than 16) |
high_threshold_writes |
int8 |
Number of I/Os for writing doublewrite files with high efficiency (the number of I/O flushing pages at a time is more than 421) |
total_pages |
int8 |
Total number of pages that are flushed to the doublewrite file area |
low_threshold_pages |
int8 |
Number of pages that are flushed with low efficiency |
high_threshold_pages |
int8 |
Number of pages that are flushed with high efficiency |
file_id |
int8 |
ID of the current doublewrite file. |
local_single_flush_dw_stat()
Description: Displays the elimination of doublewrite files on a single page in the instance.
Return type: record
local_pagewriter_stat()
Description: Displays the page flushing information and checkpoint information of the current instance.
Return type: record
local_redo_stat()
Description: Displays the replay status of the current standby instance.
Return type: record
Note: The returned replay status includes the current replay position and the replay position of the minimum restoration point.
local_recovery_status()
Description: Displays log flow control information about the primary and standby nodes.
Return type: record
local_rto_status()
Description: Displays log flow control information about the primary and standby nodes.
Return type: record
gs_wlm_switch_cgroup(sess_id int8, cgroup name)
Description: Switches the Cgroup of a specified session.
Return type: record
comm_client_info()
Description: Queries active client connections of a single node. For details about the returned result, see COMM_CLIENT_INFO.
Return type: SETOF record
pg_get_flush_lsn()
Description: Returns the position of the Xlog flushed from the current node.
Return type: text
pg_get_sync_flush_lsn()
Description: Returns the position of the Xlog flushed by the majority on the current node.
Return type: text
pgxc_wlm_rebuild_user_resource_pool()
Description: Rebuilds user and resource pool cache information. Only system administrators can execute this function.
Return type: Boolean
locktag_decode(locktag text)
Description: Parses lock details from locktag.
Example:
gaussdb=# select locktag_decode('271b:0:0:0:0:6');
locktag_decode
---------------------------------------------
locktype:transactionid, transactionid:10011
(1 row)
Return type: text
disable_conn(disconn_mode text, host text, port integer)
Description: Specifies that the CM Agent processes commands delivered by the CM Server. When a DN is selected as the primary DN, it is configured to reject connections to all DNs, forcibly connect to a DN, or connect to all DNs in polling mode. Only the initial user and system administrator can call this function.
Return type: void
Parameter |
Type |
Description |
---|---|---|
disconn_mode |
text |
DN connection mode:
|
host |
text |
IP address of the DN |
port |
integer |
Port number of the DN |
dbe_perf.get_global_full_sql_by_timestamp(start_timestamp timestamp with time zone, end_timestamp timestamp with time zone)
Description: Obtains full SQL information about a cluster. The result can be queried only in the system database but cannot be queried in the user database.
Return type: record
Parameter |
Type |
Description |
---|---|---|
start_timestamp |
timestamp with time zone |
Start point of the SQL start time range. |
end_timestamp |
timestamp with time zone |
End point of the SQL start time range. An error is reported during function execution if start_timestamp is greater than or equal to end_timestamp. |
dbe_perf.get_global_slow_sql_by_timestamp(start_timestamp timestamp with time zone, end_timestamp timestamp with time zone)
Description: Obtains cluster-level slow SQL information. The result can be queried only in the system database but cannot be queried in the user database.
Return type: record
Parameter |
Type |
Description |
---|---|---|
start_timestamp |
timestamp with time zone |
Start point of the SQL start time range. |
end_timestamp |
timestamp with time zone |
End point of the SQL start time range. An error is reported during function execution if start_timestamp is greater than or equal to end_timestamp. |
statement_detail_decode(detail text, format text, pretty boolean)
Description: Parses the details column in a full or slow SQL statement. The result can be queried only in the system database but cannot be queried in the user database.
Return type: text
Parameter |
Type |
Description |
---|---|---|
detail |
text |
Set of events generated by the SQL statement (unreadable). |
format |
text |
Parsing output format. The value is plaintext. |
pretty |
Boolean |
Specifies whether to display the text in pretty format when format is set to plaintext. The options are as follows:
|
pgxc_get_csn(tid)
Description: Returns the transaction commit sequence number (CSN) corresponding to a given transaction ID.
Return type: int8
pgxc_get_csn(tid, bucketid)
Description: Returns the transaction commit sequence number (CSN) corresponding to the transaction ID of the specified bucket ID. The input parameter bucketid indicates the physical bucket ID of the hash bucket table. For an ordinary table, the value is –1.
Return type: int8
get_global_user_transaction()
Description: Returns transaction information about each user on all nodes.
Return type: node_name name, usename name, commit_counter bigint, rollback_counter bigint, resp_min bigint, resp_max bigint, resp_avg bigint, resp_total bigint, bg_commit_counter bigint, bg_rollback_counter bigint, bg_resp_min bigint, bg_resp_max bigint, bg_resp_avg bigint, bg_resp_total bigint, and dbid oid
pg_collation_for()
Description: Returns the sorting rule corresponding to the input parameter string.
Parameter: any (Explicit type conversion is required for constants.)
Return type: text
pgxc_unlock_for_sp_database(name Name)
Description: Releases a specified database lock.
Parameter: database name
Return type: Boolean
pgxc_lock_for_sp_database(name Name)
Description: Locks a specified database.
Parameter: database name
Return type: Boolean
pgxc_unlock_for_transfer(name Name)
Description: Releases the lock used for data transmission (data redistribution).
Parameter: database name
Return type: Boolean
pgxc_lock_for_transfer(name Name)
Description: Locks the database for data transmission (data redistribution).
Parameter: database name
Return type: Boolean
gs_comm_proxy_thread_status()
Description: Collects statistics on data packets sent and received by the proxy communications library comm_proxy when a user-mode network is configured for the cluster. This function is not supported in the current version.
Parameter: nan
Return type: record
gs_catalog_attribute_records()
Description: Returns the definition of each column in a system catalog specified by OID. Only ordinary system catalogs whose OIDs are less than 10000 are supported. Indexes and TOAST tables are not supported.
Parameter: OID of the system catalog
Return type: record
dynamic_func_control(scope text, function_name text, action text, "{params}" text[])
Description: Dynamically enables built-in functions. Currently, only full SQL statements can be dynamically enabled.
Return type: record
Parameter |
Type |
Description |
---|---|---|
scope |
text |
Scope where the function is to be dynamically enabled. Currently, only GLOBAL and LOCAL are supported. |
function_name |
text |
Function name. Currently, only STMT is supported. |
action |
text |
When function_name is set to STMT, the value of action can only be TRACK, UNTRACK, LIST, or CLEAN.
|
params |
text[] |
When function_name is set to STMT, the parameters corresponding to different actions are set as follows:
|
gs_parse_page_bypath(path text, blocknum bigint, relation_type text, read_memory boolean)
Description: Parses a specified table page and returns the path for storing the parsed content.
Return type: text
Note: Only SYSADMIN or OPRADMIN can execute this function.
Parameter |
Type |
Description |
---|---|---|
path |
text |
|
blocknum |
bigint |
|
relation_type |
text |
|
read_memory |
Boolean |
|
Example:
# Parse the information of all pages in the B-tree index file. # Before calling the function, ensure that the file path exists based on the parameter description. gaussdb=# SELECT gs_parse_page_bypath('base/16603/16394', -1, 'btree', false); gs_parse_page_bypath -------------------------------------------------------------------- gs_log_dir/dump/1663_16603_16394_-1.page (1 row) # Parse the visibility result of all blocks in the visibility map file. gaussdb=# SELECT gs_parse_page_bypath('base/12828/16771_vm', -1, 'vm', false); gs_parse_page_bypath ----------------------------------------------------------------------- gs_log_dir/dump/1663_12828_16771_-1_vm.page (1 row) # Parse the free space result of all blocks in the FSM file. gaussdb=# SELECT gs_parse_page_bypath('base/12884/16817', -1, 'fsm', false); gs_parse_page_bypath -------------------------------------------------- gs_log/dump/1663_12884_16817_4294967295_fsm.page (1 row) # Parse the commit log of block 0 in the Clog file. gaussdb=# SELECT gs_parse_page_bypath('000000000000', 0, 'clog', false); gs_parse_page_bypath -------------------------------------------------------------------- gs_log_dir/dump/000000000000.clog (1 row)
The following is an example of an exception error:
# An error is reported when the value of the block number exceeds the value range.
gaussdb=# SELECT gs_parse_page_bypath('base/12828/16777', -10, 'heap', false);
ERROR: Blocknum should be between -1 and 4294967294.
CONTEXT: referenced column: gs_parse_page_bypath
gs_xlogdump_lsn(start_lsn text, end_lsn text)
Description: Parses Xlogs within the specified LSN range and returns the path for storing the parsed content. You can use pg_current_xlog_location() to obtain the current Xlog position.
Parameters: LSN start position and LSN end position
Return type: text
Note: Only SYSADMIN or OPRADMIN can execute this function.
gs_xlogdump_xid(c_xid xid)
Description: Parses Xlogs of a specified XID and returns the path for storing the parsed content. You can use txid_current() to obtain the current XID.
Parameter: XID
Return type: text
Note: Only SYSADMIN or OPRADMIN can execute this function.
gs_xlogdump_tablepath(path text, blocknum bigint, relation_type text)
Description: Parses logs corresponding to a specified table page and returns the path for storing the parsed content.
Return type: text
Note: Only SYSADMIN or OPRADMIN can execute this function.
Parameter |
Type |
Description |
---|---|---|
path |
text |
|
blocknum |
bigint |
|
relation_type |
text |
|
gs_xlogdump_parsepage_tablepath(path text, blocknum bigint, relation_type text, read_memory boolean)
Description: Parses the specified table page and logs corresponding to the table page and returns the path for storing the parsed content. It can be regarded as one execution of gs_parse_page_bypath and gs_xlogdump_tablepath. The prerequisite for executing this function is that the table file exists. To view logs of deleted tables, call gs_xlogdump_tablepath.
Return type: text
Note: Only SYSADMIN or OPRADMIN can execute this function.
Parameter |
Type |
Description |
---|---|---|
path |
text |
|
blocknum |
bigint |
|
relation_type |
text |
|
read_memory |
Boolean |
|
gs_shared_storage_xlogdump_lsn(start_lsn text, end_lsn text, xlog_file_path text)
Description: Parses Xlogs within the specified LSN range of a specified shared disk and returns the path for storing the parsed content. You can use pg_current_xlog_location() to obtain the current Xlog position.
Return type: text
Note: Only SYSADMIN or OPRADMIN can execute this function.
Parameter |
Type |
Description |
---|---|---|
start_lsn |
text |
Start LSN of the Xlog to be parsed. |
end_lsn |
text |
End LSN of the Xlog to be parsed. |
xlog_file_path |
text |
(Optional) Path of the shared volume where the Xlog to be parsed is located. If not specified, Xlogs of all shared disks on the current CN/DN are parsed. |
gs_shared_storage_ctlinfo()
Description: Obtains information about the metadata of the shared volume on the current CN/DN.
Return type: record
Category |
Parameter |
Type |
Description |
---|---|---|---|
Output parameter |
xlog_file_path |
text |
Path of the shared volume. |
Output parameter |
system_id |
text |
The system_id value stored on the current shared volume. |
Output parameter |
term |
text |
The term value stored on the current shared volume. |
Output parameter |
xlog_file_size |
text |
Size of the space for storing Xlogs on the shared volume. |
Output parameter |
insert_tail |
text |
Minimum valid LSN on the shared volume. |
Output parameter |
insert_head |
text |
Maximum valid LSN on the shared volume. |
Output parameter |
shared_storage_flush_lsn |
text |
LSN that has been flushed to disk on the shared volume. |
gs_index_recycle_queue(Oid oid, int type, uint32 blkno)
Description: Parses the UB-tree index recycling queue information.
Return type: record
Parameter |
Type |
Description |
---|---|---|
oid |
oid |
|
type |
int |
|
blkno |
uint32 |
ID of the recycling queue page. This parameter is valid only when type is set to 2. The value of blkno ranges from 1 to 4294967294. |

This function is not supported in the distributed version. An error message will be displayed if it is used in the distributed version.
gs_stat_wal_entrytable(int64 idx)
Description: Exports the content of the write-ahead log insertion status table in the Xlog.
Return type: record
Category |
Parameter |
Type |
Description |
---|---|---|---|
Input parameter |
idx |
int64 |
|
Output parameter |
idx |
uint64 |
Records the subscripts in the corresponding array. |
Output parameter |
endlsn |
uint64 |
Records the LSN label. Determines whether the Xlog corresponding to the current entry has been completely copied to the WAL buffer.
|
Output parameter |
lrc |
int32 |
Records the corresponding LRC. |
Output parameter |
status |
uint32 |
This parameter is deprecated in the current version. The query result is 0. |
gs_walwriter_flush_position()
Description: Outputs the refresh position of write-ahead logs.
Return type: record
Category |
Parameter |
Type |
Description |
---|---|---|---|
Output parameter |
last_flush_status_entry |
int32 |
Index obtained after the Xlog flushes the tblEntry of the last flushed disk. |
Output parameter |
last_scanned_lrc |
int32 |
LRC obtained after the Xlog flushes the last tblEntry scanned last time. |
Output parameter |
curr_lrc |
int32 |
Latest LRC usage in the WALInsertStatusEntry status table. The LRC indicates the LRC value corresponding to the WALInsertStatusEntry when the next Xlog record is written. |
Output parameter |
curr_byte_pos |
uint64 |
The latest Xlog position after the Xlog is written to the WAL file, which is also the next Xlog insertion point. |
Output parameter |
prev_byte_size |
uint32 |
Length of the previous Xlog record. |
Output parameter |
flush_result |
uint64 |
Position of the current global Xlog flush. |
Output parameter |
send_result |
uint64 |
Xlog sending position on the current host. |
Output parameter |
shm_rqst_write_pos |
uint64 |
The write position of the LogwrtRqst request in the XLogCtl recorded in the shared memory. |
Output parameter |
shm_rqst_flush_pos |
uint64 |
The flush position of the LogwrtRqst request in the XLogCtl recorded in the shared memory. |
Output parameter |
shm_result_write_pos |
uint64 |
The write position of the LogwrtResult request in the XLogCtl recorded in the shared memory. |
Output parameter |
shm_result_flush_pos |
uint64 |
The flush position of the LogwrtResult request in the XLogCtl recorded in the shared memory. |
Output parameter |
curr_time |
text |
Current time. |
gs_walwriter_flush_stat(int operation)
Description: Collects statistics on the frequency of writing and synchronizing write-ahead logs, data volume, and Xlog file information.
Return type: record
Category |
Parameter |
Type |
Description |
---|---|---|---|
Input parameter |
operation |
int |
|
Output parameter |
write_times |
uint64 |
Number of times that the Xlog calls the write API. |
Output parameter |
sync_times |
uint64 |
Number of times that the Xlog calls the sync API. |
Output parameter |
total_xlog_sync_bytes |
uint64 |
Total number of backend thread requests for writing data to Xlogs. |
Output parameter |
total_actual_xlog_sync_bytes |
uint64 |
Total number of Xlogs that call the sync API for disk flushing. |
Output parameter |
avg_write_bytes |
uint32 |
Number of Xlogs written each time the XLogWrite API is called. |
Output parameter |
avg_actual_write_bytes |
uint32 |
Number of Xlogs written each time the write API is called. |
Output parameter |
avg_sync_bytes |
uint32 |
Average number of Xlogs for each synchronization request. |
Output parameter |
avg_actual_sync_bytes |
uint32 |
Actual Xlog amount of disk flushing by calling sync each time. |
Output parameter |
total_write_time |
uint64 |
Total time of calling the write operation (unit: μs). |
Output parameter |
total_sync_time |
uint64 |
Total time for calling the sync API (unit: μs). |
Output parameter |
avg_write_time |
uint32 |
Average time for calling the write API each time (unit: μs). |
Output parameter |
avg_sync_time |
uint32 |
Average time for calling the sync API each time (unit: μs). |
Output parameter |
curr_init_xlog_segno |
uint64 |
ID of the latest Xlog segment file. |
Output parameter |
curr_open_xlog_segno |
uint64 |
ID of the Xlog segment file that is being written. |
Output parameter |
last_reset_time |
text |
Time when statistics were last collected. |
Output parameter |
curr_time |
text |
Current time. |
pg_ls_tmpdir()
Description: Returns the name, size, and last modification time of each file in the temporary directory (pgsql_tmp) of the default tablespace.
Parameter: nan
Return type: record
Note: Only SYSADMIN or MONADMIN can execute this function.
Category |
Parameter |
Type |
Description |
---|---|---|---|
Output parameter |
name |
text |
File name. |
Output parameter |
size |
int8 |
File size (unit: byte). |
Output parameter |
modification |
timestamptz |
Last file modification time. |
pg_ls_tmpdir(oid)
Description: Returns the name, size, and last modification time of each file in the temporary directory (pgsql_tmp) of the specified tablespace.
Parameter: oid
Return type: record
Note: Only SYSADMIN or MONADMIN can execute this function.
Category |
Parameter |
Type |
Description |
---|---|---|---|
Input parameter |
oid |
oid |
Tablespace ID. |
Output parameter |
name |
text |
File name. |
Output parameter |
size |
int8 |
File size (unit: byte). |
Output parameter |
modification |
timestamptz |
Last file modification time. |
pg_ls_waldir()
Description: Returns the name, size, and last modification time of each file in the WAL directory.
Parameter: nan
Return type: record
Note: Only SYSADMIN or MONADMIN can execute this function.
Category |
Parameter |
Type |
Description |
---|---|---|---|
Output parameter |
name |
text |
File name. |
Output parameter |
size |
int8 |
File size (unit: byte). |
Output parameter |
modification |
timestamptz |
Last file modification time. |
gs_stat_anti_cache()
Description: Returns AntiCache statistics.
Parameter: nan
Return type: record
Category |
Parameter |
Type |
Description |
---|---|---|---|
Output parameter |
table_nums |
int8 |
Number of partitions. |
Output parameter |
table_init_size |
int8 |
Initial size of a partition. |
Output parameter |
table_max_size |
int8 |
Upper limit of the partition size. |
Output parameter |
anti_cache_upper_limit_size |
int8 |
Upper limit of the AntiCache size. |
Output parameter |
anti_cache_size |
int8 |
Real-time AntiCache size. |
Output parameter |
anti_cache_max_table_size |
int8 |
Real-time maximum partition size. |
Output parameter |
anti_cache_min_table_size |
int8 |
Real-time minimum partition size. |
gs_stat_vlog_buffer()
Description: Returns verifyLog buffer statistics.
Parameter: nan
Return type: record
Category |
Parameter |
Type |
Description |
---|---|---|---|
Output parameter |
vbuffer_write_offset |
int8 |
Vlog write location. |
Output parameter |
vbuffer_flushed_offset |
int8 |
Vlog disk flushing location. |
Output parameter |
max_vbuffer_flushed_value |
int8 |
Maximum number of bytes for vlog flushing. |
Output parameter |
min_vbuffer_flushed_vlaue |
int8 |
Minimum number of bytes for vlog flushing. |
Output parameter |
ave_vbuffer_flushed_vlaue |
int8 |
Average number of bytes for vlog flushing. |
Output parameter |
vbuffer_flush_latency |
int8 |
Vlog refresh delay. |
gs_stat_vlog_related_io()
Description: Returns I/O statistics about read and write operations on the verifylog file.
Parameter: nan
Return type: record
Category |
Parameter |
Type |
Description |
---|---|---|---|
Output parameter |
read_data_iops |
float8 |
Number of pages read from files per second. |
Output parameter |
vlog_read_iops |
float8 |
Number of pages read from vlogs per second. |
Output parameter |
vlog_write_iops |
float8 |
Number of pages written to vlogs per second. |
gs_write_term_log(void)
Description: Writes a log to record the current term value of a DN. The standby DN returns false. After the data is successfully written to the primary DN, true is returned.
Return type: Boolean
gs_stat_space(bool init)
Description: Queries the status of extended pages when the INSERT operation is performed on a Ustore table.
Return type: record
Category |
Parameter |
Type |
Description |
---|---|---|---|
Input parameter |
init |
bool |
Specifies whether to reset the statistics. |
Output parameter |
access_func |
int8 |
Total number of access times of the relation_get_buffer_for_utuple API. |
Output parameter |
cache_blk |
int8 |
Number of times that the relation_get_buffer_for_utuple API obtains buffers. |
Output parameter |
cache_succ |
int8 |
Number of times that the relation_get_buffer_for_utuple API successfully obtains buffers. |
Output parameter |
nblk_first |
int8 |
Number of times that relation_get_buffer_for_utuple obtains nblocks-1 for the first time. |
Output parameter |
nblk_first_succ |
int8 |
Number of times that relation_get_buffer_for_utuple obtains nblocks-1 successfully for the first time. |
Output parameter |
nblk_second |
int8 |
Number of times that relation_get_buffer_for_utuple obtains nblocks-1 for the second time. |
Output parameter |
nblk_second_succ |
int8 |
Number of times that relation_get_buffer_for_utuple obtains nblocks-1 successfully for the second time. |
Output parameter |
fsm_first |
int8 |
Number of times that FSM is accessed for the first time. |
Output parameter |
fsm_first_success |
int8 |
Number of times that FSM is accessed successfully for the first time. |
Output parameter |
fsm_rewrite |
int8 |
Number of FSM writeback times. |
Output parameter |
fsm_second |
int8 |
Number of times that FSM is accessed for the second time. |
Output parameter |
fsm_second_sucess |
int8 |
Number of times that FSM is accessed successfully for the second time. |
Output parameter |
prune_count |
int8 |
Number of prune times in relation_get_buffer_for_utuple. |
Output parameter |
prune_space |
int8 |
Total prune space in relation_get_buffer_for_utuple. |
Output parameter |
coprune_count |
int8 |
Number of times that joint prune is performed. |
Output parameter |
coprune_scan_blocks |
int8 |
Total number of pages scanned for joint prune. |
Output parameter |
coprune_prune_count |
int8 |
Number of joint prune times. |
Output parameter |
coprune_prune_space |
int8 |
Total space for joint prune. |
Output parameter |
con_extend_count |
int8 |
Number of concurrent extended pages. |
Output parameter |
con_extend_time |
int8 |
Total time for concurrent page extension. |
Output parameter |
single_extend_time |
int8 |
Number of single-page extension times. |
Example:
gaussdb=# SELECT * FROM gs_stat_space(false);
access_func | cache_blk | cache_succ | nblk_first | nblk_first_succ | nblk_sencond | nblk_sencond_succ | fsm_first | fsm_first_success | fsm_rewrite | fsm_
second | fsm_second_success | prune_count | prune_space | coprune_count | coprune_scan_blocks | coprune_prune_count | coprune_prune_space | con_extend_count
| con_extend_time | single_extend_count
-------------+-----------+------------+------------+-----------------+--------------+-------------------+-----------+-------------------+-------------+-----
-------+--------------------+-------------+-------------+---------------+---------------------+---------------------+---------------------+-----------------
-+-----------------+---------------------
10082397 | 10082397 | 10082235 | 88 | 78 | 47021 | 47021 | 162 | 74 | 360996 |
360996 | 270948 | 6711 | 0 | 45497 | 222619 | 0 | 0 | 3675
| 25542884 | 26791
(1 row)
Note: Pay special attention to the value of cache_succ. If it is small, the system cache is invalid. If the value of prune_space is small, the Ustore data page cleaning mechanism may be faulty. If the value of con_extend_time is too large, the Ustore concurrent page extension takes a long time.
gs_redo_upage(directory_path text, backup_path text, blocknum bigint, relation_type text, xlog_path text, lsn text)
Description: Redoes a specific Ustore data page that is backed up to a specified LSN and verifies the page in this process. If a damaged page is detected, the page is flushed to the disk and the disk flushing path, page LSN, and damage information is returned; otherwise, the page is redone to the specified LSN and flushed to the disk, and the result is returned. Only SYSADMIN or OPRADMIN can execute this function.
Return type: record
Category |
Parameter |
Type |
Description |
---|---|---|---|
Input parameter |
directory_path |
text |
Specifies the directory for storing the backup file. |
Input parameter |
backup_path |
text |
Relative path of the backup table file, which is combined with the directory where the backup file is located to form the complete path of the table file, for example, base/15635/12488. If the backup file does not exist, set this parameter to null. |
Input parameter |
blocknum |
bigint |
0 to MaxBlockNumber: block number of the corresponding page. |
Input parameter |
relation_type |
text |
|
Input parameter |
xlog_path |
text |
Absolute path of the archive log directory. |
Input parameter |
lsn |
text |
The LSN consists of two hexadecimal numbers (32 bits each), which are separated by a slash (/), for example, 2/962D1DF8. If the value is 0, the latest version is used. |
Output parameter |
output_filename |
text |
Path and name of the file to be flushed to the disk. |
Output parameter |
output_lsn |
text |
LSN of the last page redo. |
Output parameter |
corruption_desc |
text |
Page damage description. |
gs_xlogdump_bylastlsn(last_lsn text, blocknum bigint, relation_type text)
Description: Inputs a page LSN and block number, parses the WAL corresponding to the LSN, obtains the last LSN of the corresponding block number, continues parsing until the last LSN is 0 or the WAL of an earlier version has been reused and recycled, and flushes the parsed log to a specified path. Only SYSADMIN or OPRADMIN can execute this function. This system function cannot be called by the standby node.
Return type: text
Category |
Parameter |
Type |
Description |
---|---|---|---|
Input parameter |
last_lsn |
text |
Parses the LSN of a specified page in hexadecimal notation, for example, 12BA/32CDEDDD. The LSN can be obtained using a page parsing tool (such as gs_parse_page_bypath). |
Input parameter |
blocknum |
bigint |
Specifies the logical block number of a page. Value range: –1 to MaxBlockNumber. If the block number is set to –1, the default block number is obtained from the WAL. |
Input parameter |
relation_type |
text |
Specifies the type of the page to be parsed. Valid value: uheap, ubtree, heap, btree, undo_record, and undo_slot. |
Output parameter |
output_filepath |
text |
Specifies the path for flushing WAL parsing results to disks. |
# Obtain the page LSN. # Before calling the function, ensure that the file path exists based on the parameter description. gaussdb=# SELECT * FROM gs_parse_page_bypath('base/15833/16768', 0, 'uheap', false); output_filepath --------------------------------------------------------------- data1/database/cluster/primary/data/1663_15833_16768_0.page (1 row) gaussdb=# SELECT * FROM gs_xlogdump_bylastlsn('0/4593570', -1, 'uheap'); output_filepath ------------------------------------------------------------------- /data1/database/cluster/primary/data/gs_log/dump/4593570_-1.xlog (1 row) gaussdb=# SELECT * FROM gs_xlogdump_bylastlsn('0/4593570', 0, 'ubtree'); ERROR: The input lsn 0/4593570 related xlog is not ubtree.
dbe_perf.get_full_sql_by_parent_id_and_timestamp(parent_id bigint, start_timestamp timestamp with time zone, end_timestamp timestamp with time zone)
Description: Obtains the records of database-level full SQL statements and their substatements that execute a stored procedure in a specified period based on parent_id. The result can be queried only in the system database but cannot be queried in the user database.
Return type: record
Parameter |
Type |
Description |
---|---|---|
parent_id |
bigint |
Specifies the unique_sql_id of the statement calling a stored procedure. |
start_timestamp |
timestamp with time zone |
Start point of the SQL start time range. |
end_timestamp |
timestamp with time zone |
End point of the SQL start time range. |
Example:
gaussdb=# CREATE TABLE test(a int,b int); NOTICE: The 'DISTRIBUTE BY' clause is not specified. Using 'a' as the distribution column by default. HINT: Please use 'DISTRIBUTE BY' clause to specify suitable data distribution column. CREATE TABLE gaussdb=# INSERT INTO test values(1,1); INSERT 0 1 gaussdb=# CREATE PROCEDURE mypro1() as num int; gaussdb$# begin gaussdb$# INSERT INTO test values(2,2); gaussdb$# DELETE FROM test where a = 2; gaussdb$# end; gaussdb$# / CREATE PROCEDURE -- Enable the parameter to trace the substatements of the stored procedure. gaussdb=# SET instr_unique_sql_track_type = 'all'; SET -- Enable the parameter. Full statement records are generated in the dbe_perf.statement_history table. gaussdb=# SET track_stmt_stat_level = 'L0,L0'; SET gaussdb=# CALL mypro1(); mypro1 -------- (1 row) gaussdb=# SET track_stmt_stat_level = 'off,L0'; SET gaussdb=# SET instr_unique_sql_track_type = 'top'; SET -- Query key information, which is used as a function parameter. gaussdb=# SELECT query,unique_query_id,start_time,finish_time FROM dbe_perf.statement_history; query | unique_query_id | start_time | finish_time --------------------------------------+-----------------+-------------------------------+------------------------------- set track_stmt_stat_level = 'L0,L0'; | 636388010 | 2023-06-02 17:40:49.176155+08 | 2023-06-02 17:40:49.176543+08 call mypro1(); | 536458473 | 2023-06-02 17:40:59.028144+08 | 2023-06-02 17:40:59.032027+08 delete from test where a = ? | 583323884 | 2023-06-02 17:40:59.029955+08 | 2023-06-02 17:40:59.031577+08 insert into test values(?,?) | 769279931 | 2023-06-02 17:40:59.029219+08 | 2023-06-02 17:40:59.029947+08 (4 rows) -- Use unique_query_id, start time, and end time of the outer query statement as parameters to query information about the specified stored procedure and its substatements within the period. gaussdb=# SELECT query FROM dbe_perf.get_full_sql_by_parent_id_and_timestamp(536458473,'2023-06-02 17:40:59.028144+08','2023-06-02 17:40:59.032027+08'); query ------------------------------ call mypro1(); delete from test where a = ? insert into test values(?,?) (3 rows) gaussdb=# DROP PROCEDURE mypro1(); DROP PROCEDURE gaussdb=# DROP TABLE test; DROP TABLE
gs_index_dump_read(int8 reset, text out_type)
Description: Queries the buffer read information generated in the cyclic queue when an index is used to obtain a new page. The buffer read information traverses leaf pages from left to right using the same key as the index page.
Return type: record
Category |
Parameter |
Type |
Description |
---|---|---|---|
Input parameter |
reset |
int8 |
|
Input parameter |
out_type |
text |
|
Output parameter |
relfilenode |
oid |
Index relfilenode corresponding to the maximum buffer read value. |
Output parameter |
max_count |
int8 |
Maximum buffer read value. |
Output parameter |
ave_count |
int8 |
Average buffer read value. |

- Currently, this API supports only Ustore index tables.
- When this API is executed, the reset operation is performed to clear all records and set all records to 0. If you query the information again, the query result is always 0 until the information is collected next time. The following are query examples:
gaussdb=# SELECT * FROM gs_index_dump_read(0, 'all'); relfilenode | max_count | ave_count --------------+-------------+------------- | | (1 row) gaussdb=# SELECT * FROM gs_index_dump_read(1, 'all'); relfilenode | max_count | ave_count --------------+-------------+------------- 0 | 0 | 0 0 | 0 | 0 (2 rows)
pg_get_ilmdef(pidx integer)
Description: Specifies a row-store compression system function, which returns the corresponding policy information based on the input ILM policy index.
Return type: text
Category |
Parameter |
Type |
Description |
---|---|---|---|
Input parameter |
pidx |
integer |
Specifies an index of an ILM policy. |
Output parameter |
ilm_policy_info |
text |
Specifies the policy information of an ILM policy. |
gs_shared_storage_flush_stat(int operation)
Description: Collects statistics on the amount of written data, write speed, write time, amount of read data, read speed, and read time of shared disks.
Return type: record
Category |
Parameter |
Type |
Description |
---|---|---|---|
Input parameter |
operation |
int |
After the statistics function is disabled and then enabled again, the previous statistics are cleared. |
Output parameter |
stat_switch |
bool |
Specifies whether the statistics function is enabled. |
Output parameter |
write_times |
uint64 |
Number of times that the shared_storage_xlog_copy thread calls the dorado_write_xlog API. |
Output parameter |
avg_write_bytes |
uint32 |
Amount of Xlogs to be written each time the dorado_write_xlog API is called, in byte. |
Output parameter |
avg_actual_write_bytes |
uint32 |
Actual amount of Xlogs to be written each time the dorado_write_xlog API is called, in byte. |
Output parameter |
total_write_time |
uint64 |
Total time for calling the dorado_write_xlog API, in μs. |
Output parameter |
avg_write_time |
uint32 |
Average time for calling the dorado_write_xlog API each time, in μs. |
Output parameter |
avg_write_speed |
uint32 |
Average speed of calling the dorado_write_xlog API to write Xlogs, in KB/s. |
Output parameter |
avg_actual_write_speed |
uint32 |
Actual average speed of calling the dorado_write_xlog API to write Xlogs, in KB/s. |
Output parameter |
total_write_sleep_time |
uint64 |
Total sleep time of the shared_storage_xlog_copy thread. |
Output parameter |
read_times |
uint64 |
Number of times that the WAL receiver thread calls the dorado_read_xlog API. |
Output parameter |
avg_read_bytes |
uint32 |
Amount of Xlogs to be written each time the dorado_read_xlog API is called, in byte. |
Output parameter |
avg_actual_read_bytes |
uint32 |
Actual amount of Xlogs to be written each time the dorado_read_xlog API is called, in byte. |
Output parameter |
total_read_time |
uint64 |
Total time for calling the dorado_read_xlog API, in μs. |
Output parameter |
avg_read_time |
uint32 |
Average time for calling the dorado_read_xlog API each time, in μs. |
Output parameter |
avg_read_speed |
uint32 |
Average speed of calling the dorado_read_xlog API to write Xlogs, in KB/s. |
Output parameter |
avg_actual_read_speed |
uint32 |
Actual average speed of calling the dorado_read_xlog API to write Xlogs, in KB/s. |
Output parameter |
total_read_sleep_time |
uint64 |
Total sleep time of the WAL receiver thread. |
Output parameter |
stat_start_time |
timestamptz |
Start time of the statistics. If the statistics are not reset, the value is the start time of GaussDB. If the statistics are reset, the value is the last reset time. |
Output parameter |
stat_end_time |
timestamptz |
End time of the current statistics collection. If the statistics collection function is enabled, the value is the current time. If the statistics collection function is disabled, the value is the last time when the statistics collection function is disabled. |
Example:
gaussdb=# SELECT * FROM gs_shared_storage_flush_stat(1);
stat_switch | write_times | avg_write_bytes | avg_actual_write_bytes | total_write_time | avg_write_time | avg_write_speed | avg_actual_write_speed | total_write_sleep_time | read_times | avg
_read_bytes | avg_actual_read_bytes | total_read_time | avg_read_time | avg_read_speed | avg_actual_read_speed | total_read_sleep_time | stat_start_time | stat_end_time
-------------+-------------+-----------------+------------------------+------------------+----------------+-----------------+------------------------+------------------------+------------+----
------------+-----------------------+-----------------+---------------+----------------+-----------------------+-----------------------+-------------------------------+------------------------
-------
t | 43644 | 8624 | 8624 | 263922553 | 6047 | 1392 | 1392 | 26918503404 | 7451 | 140
13 | 14013 | 5321082 | 714 | 19163 | 19163 | 0 | 2023-12-18 07:18:39.766855+08 | 2023-12-18 16:29:22.757
535+08
(1 row)
gs_stat_freespace(Oid relid, Oid partid, char type, int sample_ratio)
Description: Estimates the bloat rate of a table, partitioned table, or index based on statistics or sampling, and outputs space usage statistics and bloat rate information.
Return type: record
Category |
Parameter |
Type |
Description |
---|---|---|---|
Input parameter |
relation_oid |
OID |
OID of a data table, main table of the partitioned table, or index to be queried. |
Input parameter |
partation_oid |
OID |
OID of a partitioned table, level-2 partitioned table, or local partitioned index.
|
Input parameter |
relation_type |
CHAR |
Table type:
|
Input parameter |
sample_ratio |
INT8 |
Sampling ratio. The value ranges from 0 to 100.
|
Input parameter |
read_memory |
BOOL |
Specifies whether to read pages from the memory.
|
Output parameter |
OID |
OID |
OID of a data table, partitioned table, level-2 partitioned table, or index to be queried. |
Output parameter |
INFO |
TEXT |
|

- Currently, this API supports only row-store tables. Column-store tables, time series tables, segment-page tables, hash bucket tables, local temporary tables, and global temporary tables are not supported.
- This API is used to query data on a distributed CN. The query result only indicates the statistics and bloat rate estimation of the node, excluding the information about the corresponding DN. To query the DN statistics and bloat rate estimation result, you need to connect to the DN.
Example:
-- Query ordinary table information. Create a table: drop table if exists t; create table t(a int) with (storage_type=ustore); insert into t values(generate_series(1, 110000)); Update statistics: vacuum analyze t; Estimate bloat rate: gaussdb=# select * from gs_stat_freespace((select oid from pg_class where relname='t'), 0, 'r', 0, false); oid | info -------+----------------------------------------------------------------------------------------------------------------------------------------------- -------------------------------------------------------------------- 16735 | live_tuples: 110000, dead_tuples: 0, avg_tuple_len: 4, tuple_header_size: 11, rowptr_size: 440000, page_header_size: 56, nblocks: 419, approx imate_table_size: 2113464 (Bytes), approximate expansion rate: 1.62 (1 row) Sampling information: gaussdb=# select * from gs_stat_freespace((select oid from pg_class where relname='t'), 0, 'r', 80, false); oid | info -------+----------------------------------------------------------------------------------------------------------------------------------------------- ------------------------------------------------------------------------------------------------------------------------------------------------------- ----------------------------------------- 16732 | Average page stat info: page_header_size: 28, tuple has storage: 222.22, normal tuple: 222.22, dead tuple: 0.00, unused tuple: 0.00, redirecte d tuple: 0.00, td_count: 0.00, potential_freespace: 0.00, actual_freespace: 152.00. Freespace stat info: nblocks: 45, approximate_table_size: 342495 (B ytes), approximate expansion rate: 1.08. (1 row) -- Query information about a single partition in a partitioned table. Create a table: drop table if exists t; create table t(a int) with (storage_type=ustore) partition by range(a) (partition p1 values less than(3000), partition p2 values less than(maxvalue)); insert into t values(generate_series(1, 10000)); Update statistics: vacuum analyze t; Query the OID: select oid from pg_class where relname='t'; gaussdb=# select oid from pg_class where relname='t'; oid ------- 16802 (1 row) select oid, relname, parttype from pg_partition; gaussdb=# select oid, relname, parttype from pg_partition; oid | relname | parttype -------+---------+---------- 16805 | t | r 16806 | p1 | p 16807 | p2 | p (3 rows) Estimate bloat rate: gaussdb=# select * from gs_stat_freespace(16802, 16806, 'r', 0, false); oid | info -------+----------------------------------------------------------------------------------------------------------------------------------------------- --------------------------------------------------------------- 16806 | live_tuples: 5998, dead_tuples: 0, avg_tuple_len: 4, tuple_header_size: 11, rowptr_size: 23992, page_header_size: 56, nblocks: 12, approximat e_table_size: 114634 (Bytes), approximate expansion rate: 0.86 (1 row) Sampling information: gaussdb=# select * from gs_stat_freespace(16802, 16807, 'r', 0, false); oid | info -------+----------------------------------------------------------------------------------------------------------------------------------------------- ---------------------------------------------------------------- 16807 | live_tuples: 14002, dead_tuples: 0, avg_tuple_len: 4, tuple_header_size: 11, rowptr_size: 56008, page_header_size: 56, nblocks: 27, approxima te_table_size: 267550 (Bytes), approximate expansion rate: 0.83 (1 row) -- Query information about all partitions in a partitioned table. Create a table: drop table if exists t; create table t(a int) with (storage_type=ustore) partition by range(a) (partition p1 values less than(3000), partition p2 values less than(maxvalue)); insert into t values(generate_series(1, 10000)); Update statistics: vacuum analyze t; Query the OID: select oid from pg_class where relname='t'; gaussdb=# select oid from pg_class where relname='t'; oid ------- 16802 (1 row) select oid, relname, parttype from pg_partition; gaussdb=# select oid, relname, parttype from pg_partition; oid | relname | parttype -------+---------+---------- 16805 | t | r 16806 | p1 | p 16807 | p2 | p (3 rows) Estimate bloat rate: gaussdb=# select * from gs_stat_freespace(16802, 0, 'r', 0, false); oid | info -------+----------------------------------------------------------------------------------------------------------------------------------------------- ---------------------------------------------------------------- 16806 | live_tuples: 5998, dead_tuples: 0, avg_tuple_len: 4, tuple_header_size: 11, rowptr_size: 23992, page_header_size: 56, nblocks: 12, approximat e_table_size: 114634 (Bytes), approximate expansion rate: 0.86 16807 | live_tuples: 14002, dead_tuples: 0, avg_tuple_len: 4, tuple_header_size: 11, rowptr_size: 56008, page_header_size: 56, nblocks: 27, approxima te_table_size: 267550 (Bytes), approximate expansion rate: 0.83 (2 rows) Sampling information: gaussdb=# select * from gs_stat_freespace(16802, 0, 'r', 60, false); oid | info -------+----------------------------------------------------------------------------------------------------------------------------------------------- ------------------------------------------------------------------------------------------------------------------------------------------------------- -------------------------------------------- 16806 | Average page stat info: page_header_size: 56, tuple has storage: 249.92, normal tuple: 249.92, dead tuple: 0.00, unused tuple: 0.00, redirecte d tuple: 0.00, td_count: 4.00, potential_freespace: 1034.33, actual_freespace: 1034.33. Freespace stat info: nblocks: 12, approximate_table_size: 84636 (Bytes), approximate expansion rate: 1.16. 16807 | Average page stat info: page_header_size: 56, tuple has storage: 259.30, normal tuple: 259.30, dead tuple: 0.00, unused tuple: 0.00, redirecte d tuple: 0.00, td_count: 4.00, potential_freespace: 771.70, actual_freespace: 771.70. Freespace stat info: nblocks: 27, approximate_table_size: 197532 (Bytes), approximate expansion rate: 1.12. (2 rows) -- Query ordinary index information. Create a table: drop table if exists t; create table t(a int, b int, c varchar(1000)) with (storage_type=ustore); create index on t(a); insert into t values(generate_series(1, 100000), generate_series(1, 100000), 'kjgkjature'); Update statistics: vacuum analyze t; Estimate bloat rate: gaussdb=# select * from gs_stat_freespace((select oid from pg_class where relname='t_a_idx'), 0, 'i', 0, false); oid | info -------+----------------------------------------------------------------------------------------------------------------------------------------------- ----------------------------------------------------------------------------------------------------- 16776 | live_tuples: 100000, dead_tuples: 0, origin_avg_tuple_len 4, max_align_avg_tuple_len: 8, tuple_header_size: 16, rowptr_size: 401548, page_head er_size: 24, nblocks: 387, approximate_table_size: 2838700 (Bytes), approximate expansion rate: 1.12 (1 row) Sampling information: gaussdb=# select * from gs_stat_freespace((select oid from pg_class where relname='t_a_idx'), 0, 'i', 60, false); oid | info -------+----------------------------------------------------------------------------------------------------------------------------------------------- ------------------------------------------------------------------------------------------------------------------------------------------------------- ------------------------------------------- 16776 | Average page stat info: page_header_size: 24, tuple has storage: 260.39, normal tuple: 260.39, dead tuple: 0.00, unused tuple: 0.02, redirecte d tuple: 0.00, td_count: 0.00, potential_freespace: 0.00, actual_freespace: 845.05. Freespace stat info: nblocks: 387, approximate_table_size: 3044529 (Bytes), approximate expansion rate: 1.04. (1 row) -- Query information about a single partition in a local partitioned index. Create a table: drop table if exists t; create table t(a int) with (storage_type=ustore) partition by range(a) (partition p1 values less than(3000), partition p2 values less than(maxvalue));; create index on t(a) local; insert into t values(generate_series(1, 10000)); Update statistics: vacuum analyze t; Query the OID: gaussdb=# select oid from pg_class where relname='t_a_idx'; oid ------- 16814 (1 row) gaussdb=# select oid, relname, parttype from pg_partition; oid | relname | parttype -------+----------+---------- 16811 | t | r 16812 | p1 | p 16813 | p2 | p 16815 | p1_a_idx | x 16816 | p2_a_idx | x (5 rows) Estimate bloat rate: gaussdb=# select * from gs_stat_freespace(16814, 16815, 'i', 0, false); oid | info -------+----------------------------------------------------------------------------------------------------------------------------------------------- ------------------------------------------------------------------------------------------------- 16815 | live_tuples: 10000, dead_tuples: 0, origin_avg_tuple_len 4, max_align_avg_tuple_len: 8, tuple_header_size: 16, rowptr_size: 40056, page_header _size: 24, nblocks: 14, approximate_table_size: 281400 (Bytes), approximate expansion rate: 0.41 (1 row) Sampling information: gaussdb=# select * from gs_stat_freespace(16814, 16815, 'i', 80, false); oid | info -------+----------------------------------------------------------------------------------------------------------------------------------------------- ------------------------------------------------------------------------------------------------------------------------------------------------------- ----------------------------------------- 16815 | Average page stat info: page_header_size: 24, tuple has storage: 215.93, normal tuple: 215.93, dead tuple: 0.00, unused tuple: 0.50, redirecte d tuple: 0.00, td_count: 0.00, potential_freespace: 0.00, actual_freespace: 2087.43. Freespace stat info: nblocks: 14, approximate_table_size: 91476 (B ytes), approximate expansion rate: 1.25. (1 row) -- Query information about all partitions in a local partitioned index. Create a table: drop table if exists t; create table t(a int) with (storage_type=ustore) partition by range(a) (partition p1 values less than(3000), partition p2 values less than(maxvalue));; create index on t(a) local; insert into t values(generate_series(1, 10000)); Update statistics: vacuum analyze t; Query the OID: gaussdb=# select oid from pg_class where relname='t_a_idx'; oid ------- 16814 (1 row) Estimate bloat rate: gaussdb=# select * from gs_stat_freespace(16814, 0, 'i', 0, false); oid | info -------+----------------------------------------------------------------------------------------------------------------------------------------------- ------------------------------------------------------------------------------------------------- 16815 | live_tuples: 10000, dead_tuples: 0, origin_avg_tuple_len 4, max_align_avg_tuple_len: 8, tuple_header_size: 16, rowptr_size: 40056, page_header _size: 24, nblocks: 14, approximate_table_size: 281400 (Bytes), approximate expansion rate: 0.41 16816 | live_tuples: 10000, dead_tuples: 0, origin_avg_tuple_len 4, max_align_avg_tuple_len: 8, tuple_header_size: 16, rowptr_size: 40116, page_header _size: 24, nblocks: 29, approximate_table_size: 282900 (Bytes), approximate expansion rate: 0.84 (2 rows) Sampling information: gaussdb=# select * from gs_stat_freespace(16814, 0, 'i', 80, false); oid | info -------+----------------------------------------------------------------------------------------------------------------------------------------------- ------------------------------------------------------------------------------------------------------------------------------------------------------- ------------------------------------------ 16815 | Average page stat info: page_header_size: 24, tuple has storage: 215.93, normal tuple: 215.93, dead tuple: 0.00, unused tuple: 0.50, redirecte d tuple: 0.00, td_count: 0.00, potential_freespace: 0.00, actual_freespace: 2087.43. Freespace stat info: nblocks: 14, approximate_table_size: 91476 (B ytes), approximate expansion rate: 1.25. 16816 | Average page stat info: page_header_size: 24, tuple has storage: 243.28, normal tuple: 243.28, dead tuple: 0.00, unused tuple: 0.24, redirecte d tuple: 0.00, td_count: 0.00, potential_freespace: 0.00, actual_freespace: 1323.03. Freespace stat info: nblocks: 29, approximate_table_size: 213237 ( Bytes), approximate expansion rate: 1.11. (2 rows) Abnormal input: gaussdb=# select * from gs_stat_freespace(16814, 0, 'k', 0, false); ERROR: wrong relation_type input, type should be either 'r' or 'i' gaussdb=# select * from gs_stat_freespace(16814, 0, 'i', 600, false); ERROR: wrong sample_ratio input, sample_ratio should be an integer between 0 and 100 gaussdb=# select * from gs_stat_freespace(16814, 0, 'r', 60, false); ERROR: "t_a_idx" is not a ordinary relation or toast relation.
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