STATEMENT_HISTORY

STATEMENT_HISTORY displays information about execution statements on the current node. To query this system catalog, you must have the sysadmin or monitor admin permission. The result can be queried only in the system database but cannot be queried in the user database

Table 1 STATEMENT_HISTORY columns

Name	Type	Description
dbname	name	Database name.
schemaname	name	Schema name.
origin_node	integer	Node name.
user_name	name	Username.
application_name	text	Name of the application that sends a request.
client_addr	text	IP address of the client that sends a request.
client_port	integer	Port number of the client that sends a request.
unique_query_id	bigint	ID of the unique SQL statement.
debug_query_id	bigint	ID of the debug SQL statement.
query	text	Unique SQL statement.
start_time	timestamp with time zone	Time when a statement starts.
finish_time	timestamp with time zone	Time when a statement ends.
slow_sql_threshold	bigint	Standard for slow SQL statement execution.
transaction_id	bigint	Transaction ID.
thread_id	bigint	ID of an execution thread.
session_id	bigint	Session ID of a user.
n_soft_parse	bigint	Number of soft parsing times. The value of n_soft_parse plus the value of n_hard_parse may be greater than the value of n_calls because the number of subqueries is not counted in the value of n_calls.
n_hard_parse	bigint	Number of hard parsing times. The value of n_soft_parse plus the value of n_hard_parse may be greater than the value of n_calls because the number of subqueries is not counted in the value of n_calls.
query_plan	text	Statement execution plan.
n_returned_rows	bigint	Number of rows in the result set returned by the SELECT statement.
n_tuples_fetched	bigint	Number of rows randomly scanned.
n_tuples_returned	bigint	Number of rows sequentially scanned.
n_tuples_inserted	bigint	Number of rows inserted.
n_tuples_updated	bigint	Number of rows updated.
n_tuples_deleted	bigint	Number of rows deleted.
n_blocks_fetched	bigint	Number of buffer block access times.
n_blocks_hit	bigint	Number of buffer block hits.
db_time	bigint	Valid DB time, which is accumulated if multiple threads are involved (unit: μs).
cpu_time	bigint	CPU time (unit: μs).
execution_time	bigint	Execution time in the executor (unit: μs).
parse_time	bigint	SQL parsing time (unit: μs).
plan_time	bigint	SQL plan generation time (unit: μs).
rewrite_time	bigint	SQL rewriting time (unit: μs).
pl_execution_time	bigint	Execution time of PL/pgSQL (unit: μs).
pl_compilation_time	bigint	Compilation time of PL/pgSQL (unit: μs).
data_io_time	bigint	I/O time (unit: μs).
net_send_info	text	Network status of messages sent through a physical connection, including the time (unit: μs), number of calls, and throughput (unit: byte). This can be used to analyze the network overhead of SQL statements in a distributed system and is not supported in standalone system. Example: {“time”:xxx, “n_calls”:xxx, “size”:xxx}.
net_recv_info	text	Network status of messages received through a physical connection, including the time (unit: μs), number of calls, and throughput (unit: byte). This column can be used to analyze the network overhead of SQL in a distributed system. This column is not supported in a standalone mode. Example: {“time”:xxx, “n_calls”:xxx, “size”:xxx}.
net_stream_send_info	text	Network status of messages sent through a logical connection, including the time (unit: μs), number of calls, and throughput (unit: byte). This column can be used to analyze the network overhead of SQL in a distributed system. This column is not supported in a standalone mode. Example: {“time”:xxx, “n_calls”:xxx, “size”:xxx}.
net_stream_recv_info	text	Network status of messages received through a logical connection, including the time (unit: μs), number of calls, and throughput (unit: byte). This column can be used to analyze the network overhead of SQL in a distributed system. This column is not supported in a standalone mode. Example: {“time”:xxx, “n_calls”:xxx, “size”:xxx}.
lock_count	bigint	Number of locks.
lock_time	bigint	Time required for locking.
lock_wait_count	bigint	Number of lock waits.
lock_wait_time	bigint	Time required for lock waiting.
lock_max_count	bigint	Maximum number of locks.
lwlock_count	bigint	Number of lightweight locks (reserved).
lwlock_wait_count	bigint	Number of lightweight lock waits.
lwlock_time	bigint	Time required for lightweight locking (reserved).
lwlock_wait_time	bigint	Time required for lightweight lock waiting.
details	bytea	List of statement lock events, which are recorded in time sequence. The number of records is affected by the track_stmt_details_size parameter. Events include: - Start locking. - Complete locking. - Start lock waiting. - Complete lock waiting. - Start unlocking. - Complete unlocking. - Start lightweight lock waiting. - Complete lightweight lock waiting.
is_slow_sql	boolean	Whether the SQL statement is a slow SQL statement.
trace_id	text	Trace ID transmitted by a driver which is related to one application request.

This feature corresponding to the system catalog statement_history. Its main purpose is to record SQL statements and running information generated during the database running, to ensure that the SQL information can still be queried even if the database is restarted.

General usage syntax:

MogDB=# select * from DBE_PERF.statement_history;

It is mainly controlled by the following parameters:

log_duration: indicates whether to record slow queries.
log_min_duration_statement: marks the slow query time (unit: millisecond) of a SQL statement. 0 indicates that the slow query time of all SQL statements is recorded. -1 indicates that no information is recorded.
track_stmt_stat_level: The default value is OFF, L0. If the first value is not OFF, all SQL statements are recorded. If the first value is OFF and the second value is not OFF, only slow SQL statements are recorded.
track_stmt_parameter: tracks the statement in detail.

The code logic needs to meet one of the following conditions:

Dynamic statement tracking is enabled: STMT is tracked using dynamic_func_control.
track_stmt_stat_level tracks a SQL statement whose first value is L0 or higher.
track_stmt_stat_level tracks a SQL statement whose second value is L0 or higher. The statement runtime is greater than the value of log_min_duration_statement, the value of log_min_duration_statement is greater than or equal to 0, and track_stmt_statement is not enabled.
track_stmt_parameter is enabled and the first value of track_stmt_stat_level (consumed DBTIME) is greater than 0.

Issue

STATEMENT_HISTORY

Related Feature