MySQL 8.3 Release Notes
The MySQL Performance Schema provides instrumentation for performance monitoring of Group Replication memory usage. To view the available Group Replication instrumentation, issue the following query:
mysql> SELECT NAME,ENABLED FROM performance_schema.setup_instruments
WHERE NAME LIKE 'memory/group_rpl/%';
+-------------------------------------------------------------------+---------+
| NAME | ENABLED |
+-------------------------------------------------------------------+---------+
| memory/group_rpl/write_set_encoded | YES |
| memory/group_rpl/certification_data | YES |
| memory/group_rpl/certification_data_gc | YES |
| memory/group_rpl/certification_info | YES |
| memory/group_rpl/transaction_data | YES |
| memory/group_rpl/sql_service_command_data | YES |
| memory/group_rpl/mysql_thread_queued_task | YES |
| memory/group_rpl/message_service_queue | YES |
| memory/group_rpl/message_service_received_message | YES |
| memory/group_rpl/group_member_info | YES |
| memory/group_rpl/consistent_members_that_must_prepare_transaction | YES |
| memory/group_rpl/consistent_transactions | YES |
| memory/group_rpl/consistent_transactions_prepared | YES |
| memory/group_rpl/consistent_transactions_waiting | YES |
| memory/group_rpl/consistent_transactions_delayed_view_change | YES |
| memory/group_rpl/GCS_XCom::xcom_cache | YES |
| memory/group_rpl/Gcs_message_data::m_buffer | YES |
+-------------------------------------------------------------------+---------+For more information on Performance Schema's memory instrumentation and events, see Section 29.12.20.10, “Memory Summary Tables”.
Performance Schema Group Replication instruments memory allocation for Group Replication. The memory/group_rpl/ Performance Schema instrumentation contains the following instruments:
-
write_set_encoded: Memory allocated to encode the write set before it is broadcast to the group members. -
Gcs_message_data::m_buffer: Memory allocated for the transaction data payload sent to the network. -
certification_data: Memory allocated for certification of incoming transactions. -
certification_data_gc: Memory allocated for the GTID_EXECUTED sent by each member for garbage collection. -
certification_info: Memory allocated for storage of certification information allocated to resolve conflicts between concurrent transactions. -
transaction_data: Memory allocated for incoming transactions queued for the plugin pipeline. -
message_service_received_message: Memory allocated to receiving messages from Group Replication delivery message service. -
sql_service_command_data: Memory allocated for processing the queue of internal SQL service commands. -
mysql_thread_queued_task: Memory allocated when a MySQL-thread dependent task is added to the processing queue. -
message_service_queue: Memory allocated for queued messages of the Group Replication delivery message service. -
GCS_XCom::xcom_cache: Memory allocated to XCOM ache for messaging and metadata exchanged between group members as part of the consensus protocol. -
consistent_members_that_must_prepare_transaction: Memory allocated to hold list of members preparing transaction for Group Replication transaction consistency guarantees. -
consistent_transactions: Memory allocated to hold transaction and list of members that must prepare that transaction for Group Replication transaction consistency guarantees. -
consistent_transactions_prepared: Memory allocated to hold list of transaction's info prepared for the Group Replication Transaction Consistency Guarantees. -
consistent_transactions_waiting: Memory allocated to hold information on a list of transactions while preceding prepared transactions with consistency ofAFTERandBEFORE_AND_AFTERare processed. -
consistent_transactions_delayed_view_change: Memory allocated to hold list of view change events (view_change_log_event) delayed by prepared consistent transactions waiting for prepare acknowledgement. -
group_member_info: Memory allocated to hold the group member properties. Properties such as hostname, port, member weight and role, and so on.
The following instruments in the memory/sql/ grouping are also used to monitor Group Replication memory:
-
Log_event: Memory allocated for encoding transaction data into the binary log format; this is the same format in which Group Replication transmits data. -
write_set_extraction: Memory allocated to the transaction's generated write set before it is committed. -
Gtid_set::to_string: Memory allocated to stored the string representation of a GTID set. -
Gtid_set::Interval_chunk: Memory allocated to store the GTID object.