next_idx(time_next , epoch) ) comment 'vitess_message ,vt_ack_wait=30,vt_purge_after=86400,vt_batch_size=10,vt_cache_size=10000,vt_poller_interval=30' The application-related columns are as follows: • id: can be any (1 day). • vt_batch_size=10: Send up to 10 messages per RPC packet. • vt_cache_size=10000: Store up to 10000 messages in the cache. If the demand is higher, the rest of the items will have to wait for the example: create table user_seq(id int, next_id bigint, cache bigint, primary key(id)) comment 'vitess_sequence'; insert into user_seq(id, next_id , cache) values(0, 1, 100); Then, the Sequence has to be

handled. System variable Handled autocommit VitessAware client_found_rows VitessAware skip_query_plan_cache VitessAware tx_read_only VitessAware transaction_read_only VitessAware sql_select_limit VitessAware max_insert_delayed_threads NoOp multi_range_count NoOp net_buffer_length NoOp new NoOp query_cache_type NoOp query_cache_wlock_invalidate NoOp query_prealloc_size NoOp sql_buffer_result NoOp transaction_alloc_block_size historian runs on both master and replica and handles DDL events. For a given GTID it looks up its cache to check if it has a schema valid for that GTID. If not, on the replica, it looks up the schema_version

handled. System variable Handled autocommit VitessAware client_found_rows VitessAware skip_query_plan_cache VitessAware tx_read_only VitessAware transaction_read_only VitessAware sql_select_limit VitessAware max_insert_delayed_threads NoOp multi_range_count NoOp net_buffer_length NoOp new NoOp query_cache_type NoOp query_cache_wlock_invalidate NoOp query_prealloc_size NoOp sql_buffer_result NoOp transaction_alloc_block_size historian runs on both master and replica and handles DDL events. For a given GTID it looks up its cache to check if it has a schema valid for that GTID. If not, on the replica, it looks up the schema_version

handled. System variable Handled autocommit VitessAware client_found_rows VitessAware skip_query_plan_cache VitessAware tx_read_only VitessAware transaction_read_only VitessAware sql_select_limit VitessAware max_insert_delayed_threads NoOp multi_range_count NoOp net_buffer_length NoOp new NoOp query_cache_type NoOp query_cache_wlock_invalidate NoOp query_prealloc_size NoOp sql_buffer_result NoOp transaction_alloc_block_size historian runs on both master and replica and handles DDL events. For a given GTID it looks up its cache to check if it has a schema valid for that GTID. If not, on the replica, it looks up the schema_version

handled. System variable Handled autocommit VitessAware client_found_rows VitessAware skip_query_plan_cache VitessAware tx_read_only VitessAware transaction_read_only VitessAware sql_select_limit VitessAware max_insert_delayed_threads NoOp multi_range_count NoOp net_buffer_length NoOp new NoOp query_cache_type NoOp query_cache_wlock_invalidate NoOp query_prealloc_size NoOp sql_buffer_result NoOp transaction_alloc_block_size next_idx(time_next , epoch) ) comment 'vitess_message ,vt_ack_wait=30,vt_purge_after=86400,vt_batch_size=10,vt_cache_size=10000,vt_poller_interval=30' The application-related columns are as follows: • id: can be any

handled. System variable Handled autocommit VitessAware client_found_rows VitessAware skip_query_plan_cache VitessAware tx_read_only VitessAware transaction_read_only VitessAware sql_select_limit VitessAware max_insert_delayed_threads NoOp multi_range_count NoOp net_buffer_length NoOp new NoOp query_cache_type NoOp query_cache_wlock_invalidate NoOp query_prealloc_size NoOp sql_buffer_result NoOp transaction_alloc_block_size historian runs on both primary and replica and handles DDL events. For a given GTID it looks up its cache to check if it has a schema valid for that GTID. If not, on the replica, it looks up the schema_version

next_idx(time_next , epoch) ) comment 'vitess_message ,vt_ack_wait=30,vt_purge_after=86400,vt_batch_size=10,vt_cache_size=10000,vt_poller_interval=30' The application-related columns are as follows: • id: can be any (1 day). • vt_batch_size=10: Send up to 10 messages per RPC packet. • vt_cache_size=10000: Store up to 10000 messages in the cache. If the demand is higher, the rest of the items will have to wait for the example: create table user_seq(id int, next_id bigint, cache bigint, primary key(id)) comment 'vitess_sequence'; insert into user_seq(id, next_id , cache) values(0, 1, 100); Then, the Sequence has to be

of serving a very large number of such ids because values are cached and served out of memory. The cache value is configurable. The VSchema allows you to associate a column of a table with the sequence next_id bigint, cache bigint, primary key(id)) comment 'vitess_sequence'; insert into customer_seq(id, next_id , cache) values(0, 1000, 100); create table order_seq(id int, next_id bigint, cache bigint, primary primary key(id)) comment 'vitess_sequence'; insert into order_seq(id, next_id , cache) values(0, 1000, 100); Note the vitess_sequence comment in the create table statement. VTTablet will use this metadata

performace • java < go < c/c++ Vitess Features • dynamic resharding • auto-failover • row-cache • limit inefficiency SQL • more client connection • replication lag optimization • multi data Filter • Backup • Restore • Diffs • Row Limit • Kill Timeout SQL • Query blacklisting • row cache • more stats & monitor Vttablet Structure Vitess Resharding • read scaling up ? —> replica

https://github.com/vitessio/vitess/blob/a49702d9f9782c14d96030c8d2771c8decb39948/g o/vt/discovery/tablets_cache_status.go#L57 func (tcs *TabletsCacheStatus) StatusAsHTML() template.HTML { tLinks := make([]string