Performance Schema Connection Tables | events_stages_summary_by_account_by_event_name | | events_stages_summary_by_host_by_event_name | | events_stages_summary_by_user_by_event_name | | events_statements_summary_by_account_by_event_name | | events_statements_summary_by_host_by_event_name | | events_statements_summary_by_user_by_event_name | | events_transactions_summary_by_account_by_event_name | | events_transactions_summary_by_host_by_event_name | | events_transactions_summary_by_user_by_event_name | | events_waits_summary_by_account_by_event_name | | events_waits_summary_by_host_by_event_name | | events_waits_summary_by_user_by_event_name | | memory_summary_by_account_by_event_name | | memory_summary_by_host_by_event_name | | memory_summary_by_user_by_event_name | +------------------------------------------------------+ Truncated Connection Table Implicitly Truncated Summary Tables accounts Tables with names containing _summary_by_account ,  _summary_by_thread hosts Tables with names containing _summary_by_account ,  _summary_by_host , _summary_by_thread users Tables with names containing _summary_by_account ,  _summary_by_user , _summary_by_thread Table 27.2 Implicit Effects of Connection Table Truncation 27.12.8.1 The accounts Table 4990 Truncating a  _summary_global  summary table also implicitly truncates its corresponding connection and thread summary tables. For example, truncating  events_waits_summary_global_by_event_name implicitly truncates the wait event summary tables that are aggregated by account, host, user, or thread. The  accounts  table contains a row for each account that has connected to the MySQL server. For each account, the table counts the current and total number of connections. The table size is autosized at server TRUNCATE TABLE  is permitted for connection summary tables. It removes rows for accounts, hosts, or users with no connections, and resets the summary columns to zero for the remaining rows. In addition, each summary table that is aggregated by account, host, user, or thread is implicitly truncated by truncation of the connection table on which it depends. The following table describes the relationship between connection table truncation and implicitly truncated tables. For details about individual connection summary tables, consult the section that describes tables for the summarized event type: •Error event summaries: Section 27.12.20.11, “Error Summary Tables” •Memory event summaries: Section 27.12.20.10, “Memory Summary Tables” •Transaction event summaries: Section 27.12.20.5, “Transaction Summary Tables” •Statement event summaries: Section 27.12.20.3, “Statement Summary Tables” •Stage event summaries: Section 27.12.20.2, “Stage Summary Tables” •Wait event summaries: Section 27.12.20.1, “Wait Event Summary Tables”