Querying Tables Related to Parallel Query Information Monitoring

Table INFORMATION_SCHEMA.KOVAE_THREADS_LIST

The INFORMATION_SCHEMA.KOVAE_THREADS_LIST table is used to query the thread usage of the current parallel query.

**Table 1** Fields in the INFORMATION_SCHEMA.KOVAE_THREADS_LIST table
Field	Field Type	Description
Id	int	Unique ID of a session connection, which corresponds to the ID column in processlist
type	varchar	Thread type. Currently, the main and worker types are supported: main: main thread of a session worker: worker parallel thread of a session
User	varchar	User name of a session connection
Host	varchar	IP address and port number of the client connected to the session
Command	varchar	Command that is being executed by a session connection
ThreadId	int	Thread ID, corresponding to the thread ID on the OS
Time	int	Statistics about the thread running time, in milliseconds In parallel queries, if the record in the current row is the main thread of the session connection, the total running time of all worker threads in the session is displayed. If the record in the current row is the worker thread of the session connection, the running time of that worker thread is displayed.

Table INFORMATION_SCHEMA.KOVAE_MEMORY_ACTIVE

The INFORMATION_SCHEMA.KOVAE_MEMORY_ACTIVE table is used to query the memory usage of the session where parallel queries are being executed.

**Table 2** Fields in the INFORMATION_SCHEMA.KOVAE_MEMORY_ACTIVE table
Column Name	Data Type	Description
SESSION_ID	MYSQL_TYPE_LONG	Session ID
SQL	MYSQL_TYPE_STRING	SQL statement
TIMESTAMP	MYSQL_TYPE_TIME	Timestamp
OPERATOR_ID	MYSQL_TYPE_LONG	Operator ID
OPERATOR	MYSQL_TYPE_STRING	Execution operator
USED_MEMORY	MYSQL_TYPE_LONGLONG	Size of the used memory
PEAK_MEMORY	MYSQL_TYPE_LONGLONG	Peak memory size

Table INFORMATION_SCHEMA.KOVAE_MEMORY_HISTORY

The INFORMATION_SCHEMA.KOVAE_MEMORY_HISTORY table records the memory usage information that is queried recently. The value of kovae_memory_save_num is the number of queried records.

**Table 3** Fields in the INFORMATION_SCHEMA.KOVAE_MEMORY_HISTORY table
Column Name	Data Type	Description
SESSION_ID	MYSQL_TYPE_LONG	Session ID
SQL	MYSQL_TYPE_STRING	SQL statement
TIMESTAMP	MYSQL_TYPE_TIME	Timestamp
OPERATOR_ID	MYSQL_TYPE_LONG	Operator ID
OPERATOR	MYSQL_TYPE_STRING	Execution operator
USED_MEMORY	MYSQL_TYPE_LONGLONG	Memory size when the execution ends
PEAK_MEMORY	MYSQL_TYPE_LONGLONG	Peak memory size

Table INFORMATION_SCHEMA.KOVAE_STATEMENT_HISTORY

The INFORMATION_SCHEMA.KOVAE_STATEMENT_HISTORY table displays the SQL statements that have been executed in KOVAE. The maximum number of rows that can be displayed is specified by kovae_statement_history_schema_size.

**Table 4** Fields in the INFORMATION_SCHEMA.KOVAE_STATEMENT_HISTORY table
Column Name	Data Type	Description
SESSION_ID	MYSQL_TYPE_LONGLONG	Session ID of the current query (ID of the session thread)
QUERY_ID	MYSQL_TYPE_LONGLONG	SQL statement ID of the current query
USER	MYSQL_TYPE_STRING	User name of the current query
HOST	MYSQL_TYPE_STRING	IP address and port number of the current query
QUERY_STATEMENT	MYSQL_TYPE_STRING	SQL information of the current query
TIMER_START	MYSQL_TYPE_LONGLONG	Start timestamp of the current query (from 1970-01-01 00:00:00 to the query start time, in nanoseconds)
TIMER_END	MYSQL_TYPE_LONGLONG	End timestamp of the current query (from 1970-01-01 00:00:00 to the query end time, in nanoseconds)

Table INFORMATION_SCHEMA.KOVAE_THREADS_HISTORY

The INFORMATION_SCHEMA.KOVAE_THREADS_HISTORY table displays the used worker threads (WORKER_THREAD_ID) during the parallel execution of the SQL statement (QUERY_ID) in KOVAE. The maximum number of rows that can be displayed is the value of kovae_threads_history_schema_size.

The KOVAE_STATEMENT_HISTORY table is associated with the KOVAE_THREADS_HISTORY table through QUERY_ID to obtain the start time and end time of each worker thread during the SQL statement execution.

**Table 5** Fields in the INFORMATION_SCHEMA.KOVAE_THREADS_HISTORY table
Column Name	Data Type	Description
QUERY_ID	MYSQL_TYPE_LONGLONG	SQL statement ID of the current query
WORKER_THREAD_ID	MYSQL_TYPE_LONGLONG	Worker thread ID of the current query
TIMER_START	MYSQL_TYPE_LONGLONG	Start timestamp of the worker thread execution in the current query (from 1970-01-01 00:00:00 to the query start time, in nanoseconds)
TIMER_END	MYSQL_TYPE_LONGLONG	End timestamp of the worker thread execution in the current query (from 1970-01-01 00:00:00 to the query end time, in nanoseconds)

Table INFORMATION_SCHEMA.KOVAE_MEMORY_DETAIL_HISTORY

The INFORMATION_SCHEMA.KOVAE_MEMORY_DETAIL_HISTORY table displays to answer the three questions: During the parallel execution of the SQL statement (QUERY_ID) in KOVAE, which worker threads (WORKER_THREAD_ID) request or release what amount of memory in which modules? The maximum number of rows that can be displayed is the value of kovae_memory_detail_history_schema_size. Based on the time value and number of bytes of the operation, the memory usage trend curve of the SQL statement execution in KOVAE can be obtained.

**Table 6** Fields in the INFORMATION_SCHEMA.KOVAE_MEMORY_DETAIL_HISTORY table
Column Name	Data Type	Description
QUERY_ID	MYSQL_TYPE_LONGLONG	SQL statement ID of the current operation
WORKER_THREAD_ID	MYSQL_TYPE_LONGLONG	Worker thread ID of the current operation
SOURCE	MYSQL_TYPE_STRING	Module for the current operation, the phase name or operator name of the SQL statement execution in KOVAE
OPERATE	MYSQL_TYPE_STRING	Operation type (malloc: request for memory; free: release memory)
POINTER	MYSQL_TYPE_LONGLONG	Identifier value of the memory handle in the current operation
NUMBER_OF_BYTES	MYSQL_TYPE_LONGLONG	Number of bytes in the memory of the current operation
TIMER_STAMP	MYSQL_TYPE_LONGLONG	Timestamp of the current operation (from 1970-01-01 00:00:00 to the operation time, in nanoseconds)

Table INFORMATION_SCHEMA.KOVAE_BUFFER_DETAIL_HISTORY

The INFORMATION_SCHEMA.KOVAE_BUFFER_DETAIL_HISTORY table displays to answer the three questions: During the parallel execution of the SQL statement (QUERY_ID) in KOVAE, which worker threads (WORKER_THREAD_ID) in which modules occupy what amount of cache (key cache concerned by the service, such as the sorting cache of the Sort operator and the hash cache of HashAgg, HashJoin, and Material)? The maximum number of rows that can be displayed is the value of kovae_buffer_detail_history_schema_size.

**Table 7** Fields in the INFORMATION_SCHEMA.KOVAE_BUFFER_DETAIL_HISTORY table
Column Name	Data Type	Description
QUERY_ID	MYSQL_TYPE_LONGLONG	SQL statement ID of the current operation
WORKER_THREAD_ID	MYSQL_TYPE_LONGLONG	Worker thread ID of the current operation
SOURCE	MYSQL_TYPE_STRING	Module for the current operation, the phase name or operator name of the SQL statement execution in KOVAE
OPERATE	MYSQL_TYPE_STRING	Operation type
POINTER	MYSQL_TYPE_LONGLONG	Identifier value of the cache handle in the current operation
NUMBER_OF_BYTES	MYSQL_TYPE_LONGLONG	Number of bytes in the cache of the current operation
TIMER_STAMP	MYSQL_TYPE_LONGLONG	Timestamp of the current operation (from 1970-01-01 00:00:00 to the operation time, in nanoseconds)

Procedure

Log in to the MySQL service through the MySQL client.
Check the INFORMATION_SCHEMA table. Use the INFORMATION_SCHEMA.KOVAE_THREADS_LIST table as an example:
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select * from information_schema.KOVAE_THREADS_LIST;

Parent topic: Feature Usage