. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84 Transaction Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . snapshot, queries must be sent to the master within a transaction. For read-after-write consistency, reading from the master without a transaction is sufficient. To summarize, these are the various levels in-flight query for any identical requests received while the in-flight query was still executing. – Transaction manager – Limit number of concurrent transactions and manage deadlines to optimize overall throughput

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99 Transaction Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . VitessAware skip_query_plan_cache VitessAware tx_read_only VitessAware transaction_read_only VitessAware sql_select_limit VitessAware transaction_mode VitessAware workload VitessAware charset VitessAware names query_cache_type NoOp query_cache_wlock_invalidate NoOp query_prealloc_size NoOp sql_buffer_result NoOp transaction_alloc_block_size NoOp wait_timeout NoOp audit_log_read_buffer_size NotSupported auto_increment_increment

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86 Transaction Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . VitessAware skip_query_plan_cache VitessAware tx_read_only VitessAware transaction_read_only VitessAware sql_select_limit VitessAware transaction_mode VitessAware workload VitessAware charset VitessAware names query_cache_type NoOp query_cache_wlock_invalidate NoOp query_prealloc_size NoOp sql_buffer_result NoOp transaction_alloc_block_size NoOp wait_timeout NoOp audit_log_read_buffer_size NotSupported auto_increment_increment

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119 Transaction Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . VitessAware skip_query_plan_cache VitessAware tx_read_only VitessAware transaction_read_only VitessAware sql_select_limit VitessAware transaction_mode VitessAware workload VitessAware 25 System variable Handled query_cache_type NoOp query_cache_wlock_invalidate NoOp query_prealloc_size NoOp sql_buffer_result NoOp transaction_alloc_block_size NoOp wait_timeout NoOp audit_log_read_buffer_size NotSupported auto_increment_increment

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95 Transaction Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . VitessAware skip_query_plan_cache VitessAware tx_read_only VitessAware transaction_read_only VitessAware sql_select_limit VitessAware transaction_mode VitessAware workload VitessAware charset VitessAware names query_cache_type NoOp query_cache_wlock_invalidate NoOp query_prealloc_size NoOp sql_buffer_result NoOp transaction_alloc_block_size NoOp wait_timeout NoOp audit_log_read_buffer_size NotSupported auto_increment_increment

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104 Transaction Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . VitessAware skip_query_plan_cache VitessAware tx_read_only VitessAware transaction_read_only VitessAware sql_select_limit VitessAware transaction_mode VitessAware workload VitessAware charset VitessAware names query_cache_type NoOp query_cache_wlock_invalidate NoOp query_prealloc_size NoOp sql_buffer_result NoOp transaction_alloc_block_size NoOp wait_timeout NoOp 22 System variable Handled audit_log_read_buffer_size

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 Transaction Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . snapshot, queries must be sent to the master within a transaction. For read-after-write consistency, reading from the master without a transaction is sufficient. To summarize, these are the various levels in-flight query for any identical requests received while the in-flight query was still executing. – Transaction manager – Limit number of concurrent transactions and manage deadlines to optimize overall throughput

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 Transaction Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . to live together to support in-shard joins? • Do we want certain rows that will be in the same transaction to live together? Using the above considerations, in our use case, we can determine that: • For snapshot, queries must be sent to the master within a transaction. For read-after-write consistency, reading from the master without a transaction is sufficient. To summarize, these are the various levels

distinct, orderBy, insert, delete, update. • cross-shard index • cross-shard joins • distribute transaction • sync replication • part of second index Vitess 参考资料 • https://code.google.com/p/vitess/