MySQL Protocol TiK V TiK V TiFlas h TiK V TiK V ... DistSQL API KV API ... Worker Worke r Worke r Spark Driver ... Spark SQL Spark Cluster DistSQL API P D P D P D PD Cluster Pum p Pum p Pum p Draine

Region 2” TiDB TiDB TiDB Application via MySQL Protocol TiKV TiKV TiKV TiKV TiKV TiKV ... ... DistSQL API KV API PD PD PD Metadata/ Data location TSO/ Metadata TiDB architecture Pros: ● Scale-out global tidb_hashagg_partial_concurrency=16; set global tidb_projection_concurrency=4; set global tidb_distsql_scan_concurrency=20; set global tidb_index_lookup_concurrency=20; set global tidb_index_join_batch_size=25000;

response time of the corresponding TiKV address and the Region logs in PD and KV at that time. • 7.1.5 distsql.go reports inconsistent index. The data index seems to be inconsistent. Run the admin check table memory problems caused by high concurrency. The corresponding system variables include: • tidb_distsql_scan_concurrency • tidb_index_serial_scan_concurrency • tidb_executor_concurrency • The concurrency pd_client_cmd_handle_cmds_duration_seconds{type="wait"} + req_per_copr * ( tidb_distsql_handle_query_duration_seconds{sql_type="general"} ) tidb_distsql_handle_query_duration_seconds{sql_type="general"} <= send �→ request

@dveeden 2.2.2.3 System variables 43 Variable name Change type Description tidb_ �→ analyze �→ _ �→ distsql �→ _ �→ scan �→ _ �→ concurrency �→ Modified Changes the mini- mum value from 1 to 0. When you set response time of the corresponding TiKV address and the Region logs in PD and KV at that time. • 7.1.5 distsql.go reports inconsistent index. The data index seems to be inconsistent. Run the admin check table memory problems caused by high concurrency. The corresponding system variables include: • tidb_distsql_scan_concurrency • tidb_index_serial_scan_concurrency • tidb_executor_concurrency • The concurrency

response time of the corresponding TiKV address and the Region logs in PD and KV at that time. • 7.1.5 distsql.go reports inconsistent index. The data index seems to be inconsistent. Run the admin check table memory problems caused by high concurrency. The corresponding system variables include: • tidb_distsql_scan_concurrency • tidb_index_serial_scan_concurrency • tidb_executor_concurrency • The concurrency pd_client_cmd_handle_cmds_duration_seconds{type="wait"} + req_per_copr * ( tidb_distsql_handle_query_duration_seconds{sql_type="general"} ) tidb_distsql_handle_query_duration_seconds{sql_type="general"} <= send �→ request

response time of the corresponding TiKV address and the Region logs in PD and KV at that time. • 7.1.5 distsql.go reports inconsistent index. The data index seems to be inconsistent. Run the admin check table memory problems caused by high concurrency. The corresponding system variables include: • tidb_distsql_scan_concurrency • tidb_index_serial_scan_concurrency • tidb_executor_concurrency • The concurrency pd_client_cmd_handle_cmds_duration_seconds{type="wait"} + req_per_copr * ( tidb_distsql_handle_query_duration_seconds{sql_type="general"} ) tidb_distsql_handle_query_duration_seconds{sql_type="general"} <= send �→ request

response time of the corresponding TiKV address and the Region logs in PD and KV at that time. • 7.1.5 distsql.go reports inconsistent index. The data index seems to be inconsistent. Run the admin check table memory problems caused by high concurrency. The corresponding system variables include: • tidb_distsql_scan_concurrency • tidb_index_serial_scan_concurrency • tidb_executor_concurrency • The concurrency pd_client_cmd_handle_cmds_duration_seconds{type="wait"} + req_per_copr * ( tidb_distsql_handle_query_duration_seconds{sql_type="general"} ) tidb_distsql_handle_query_duration_seconds{sql_type="general"} <= send �→ request

支持解析并忽略该选项，以便与 MySQL 兼容 #53305 @dveeden 2.2.2.3 系统变量 39 变量名 修改类型 描述 tidb_ �→ analyze �→ _ �→ distsql �→ _scan_ �→ concurrency �→ 修改 最小值 从 1 改 为 0。当 设置为 0 时，TiDB 会根据 集群规 模自适 应调整 执行 ANALYZE 时 scan 操作的 cancelled。请求发送到 TiKV 后超时未收到 TiKV 响应。需要排查对应地址 TiKV 的 响应时间和对应 Region 在当时的 PD 和 KV 日志，确定为什么 KV 未及时响应。 • 7.1.5 distsql.go 报 inconsistent index。数据索引疑似发生不一致，首先对报错的信息中 index 所在表执 行 admin check table 命令，如果检查失败，则先通过以下命令禁用 较多内存。可 以尝试使用 STREAM_AGG() 替代。 • 调小同时读取的 Region 的数量，或降低算子并发度，以避免因高并发导致的内存问题。对应的系统变 量包括： – tidb_distsql_scan_concurrency – tidb_index_serial_scan_concurrency – tidb_executor_concurrency • 问题发生时间附近，session

cancelled。请求发送到 TiKV 后超时未收到 TiKV 响应。需要排查对应地址 TiKV 的 响应时间和对应 Region 在当时的 PD 和 KV 日志，确定为什么 KV 未及时响应。 • 7.1.5 distsql.go 报 inconsistent index。数据索引疑似发生不一致，首先对报错的信息中 index 所在表执 行 admin check table 命令，如果检查失败，则先通过以下命令禁用 较多内存。可 以尝试使用 STREAM_AGG() 替代。 • 调小同时读取的 Region 的数量，或降低算子并发度，以避免因高并发导致的内存问题。对应的系统变 量包括： – tidb_distsql_scan_concurrency – tidb_index_serial_scan_concurrency – tidb_executor_concurrency • 问题发生时间附近，session pd_client_cmd_handle_cmds_duration_seconds{type="wait"} + req_per_copr * ( tidb_distsql_handle_query_duration_seconds{sql_type="general"} ) tidb_distsql_handle_query_duration_seconds{sql_type="general"} <= send request

cancelled。请求发送到 TiKV 后超时未收到 TiKV 响应。需要排查对应地址 TiKV 的 响应时间和对应 Region 在当时的 PD 和 KV 日志，确定为什么 KV 未及时响应。 • 7.1.5 distsql.go 报 inconsistent index。数据索引疑似发生不一致，首先对报错的信息中 index 所在表执 行 admin check table 命令，如果检查失败，则先通过以下命令禁用 较多内存。可 以尝试使用 STREAM_AGG() 替代。 • 调小同时读取的 Region 的数量，或降低算子并发度，以避免因高并发导致的内存问题。对应的系统变 量包括： – tidb_distsql_scan_concurrency – tidb_index_serial_scan_concurrency – tidb_executor_concurrency • 问题发生时间附近，session pd_client_cmd_handle_cmds_duration_seconds{type="wait"} + req_per_copr * ( tidb_distsql_handle_query_duration_seconds{sql_type="general"} ) tidb_distsql_handle_query_duration_seconds{sql_type="general"} <= send request