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ADD COLUMNADD INDEXADMINADMIN CANCEL DDLADMIN CHECKSUM TABLEADMIN CHECK [TABLE|INDEX]ADMIN SHOW DDL [JOBS|QUERIES]ALTER DATABASEALTER INDEXALTER TABLEALTER TABLE COMPACTALTER USERANALYZE TABLEBATCHBEGINCHANGE COLUMNCOMMITCHANGE DRAINERCHANGE PUMPCREATE [GLOBAL|SESSION] BINDINGCREATE DATABASECREATE INDEXCREATE ROLECREATE SEQUENCECREATE TABLE LIKECREATE TABLECREATE USERCREATE VIEWDEALLOCATEDELETEDESCDESCRIBEDODROP [GLOBAL|SESSION] BINDINGDROP COLUMNDROP DATABASEDROP INDEXDROP ROLEDROP SEQUENCEDROP STATSDROP TABLEDROP USERDROP VIEWEXECUTEEXPLAIN ANALYZEEXPLAINFLASHBACK TABLEFLUSH PRIVILEGESFLUSH STATUSFLUSH TABLESGRANT <privileges>GRANT <role>INSERTKILL [TIDB]MODIFY COLUMNPREPARERECOVER TABLERENAME INDEXRENAME TABLEREPLACEREVOKE <privileges>REVOKE <role>ROLLBACKSELECTSET DEFAULT ROLESET [NAMES|CHARACTER SET]SET PASSWORDSET ROLESET TRANSACTIONSET [GLOBAL|SESSION] <variable>SHOW ANALYZE STATUSSHOW [GLOBAL|SESSION] BINDINGSSHOW BUILTINSSHOW CHARACTER SETSHOW COLLATIONSHOW [FULL] COLUMNS FROMSHOW CREATE SEQUENCESHOW CREATE TABLESHOW CREATE USERSHOW DATABASESSHOW DRAINER STATUSSHOW ENGINESSHOW ERRORSSHOW [FULL] FIELDS FROMSHOW GRANTSSHOW INDEX [FROM|IN]SHOW INDEXES [FROM|IN]SHOW KEYS [FROM|IN]SHOW MASTER STATUSSHOW PLUGINSSHOW PRIVILEGESSHOW [FULL] PROCESSSLISTSHOW PROFILESSHOW PUMP STATUSSHOW SCHEMASSHOW STATS_HEALTHYSHOW STATS_HISTOGRAMSSHOW STATS_METASHOW STATUSSHOW TABLE NEXT_ROW_IDSHOW TABLE REGIONSSHOW TABLE STATUSSHOW [FULL] TABLESSHOW [GLOBAL|SESSION] VARIABLESSHOW WARNINGSSHUTDOWNSPLIT REGIONSTART TRANSACTIONTABLETRACETRUNCATEUPDATEUSEWITH
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ANALYZE_STATUSCLIENT_ERRORS_SUMMARY_BY_HOSTCLIENT_ERRORS_SUMMARY_BY_USERCLIENT_ERRORS_SUMMARY_GLOBALCHARACTER_SETSCLUSTER_INFOCOLLATIONSCOLLATION_CHARACTER_SET_APPLICABILITYCOLUMNSDATA_LOCK_WAITSDDL_JOBSDEADLOCKSENGINESKEY_COLUMN_USAGEPARTITIONSPROCESSLISTREFERENTIAL_CONSTRAINTSSCHEMATASEQUENCESSESSION_VARIABLESSLOW_QUERYSTATISTICSTABLESTABLE_CONSTRAINTSTABLE_STORAGE_STATSTIDB_HOT_REGIONS_HISTORYTIDB_INDEXESTIDB_SERVERS_INFOTIDB_TRXTIFLASH_REPLICATIKV_REGION_PEERSTIKV_REGION_STATUSTIKV_STORE_STATUSUSER_PRIVILEGESVIEWS
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High Availability with Multi-AZ Deployments
TiDB uses the Raft consensus algorithm to ensure that data is highly available and safely replicated throughout storage in Raft Groups. Data is redundantly copied between storage nodes and placed in different availability zones to protect against machine or data center failures. With automatic failover, TiDB ensures that your service is always on.
TiDB Cloud clusters consist of three major components: TiDB node, TiKV node, and TiFlash node. The highly availability implementation of each component for Dedicated Tier is as follows:
TiDB node
TiDB is for computing only and does not store data. It is horizontally scalable. TiDB Cloud deploys TiDB nodes evenly to different availability zones in a region. When a user executes a SQL request, the request first passes through a load balancer deployed across availability zones, and then the load balancer distributes the request to different TiDB nodes for execution. It is recommended that each TiDB Cloud cluster has at least two TiDB nodes for high availability.
TiKV node
TiKV (https://docs.pingcap.com/tidb/stable/tikv-overview) is the row-based storage layer of TiDB Cloud cluster with horizontal scalability. On TiDB Cloud, the minimum number of TiKV nodes for a cluster is 3. TiDB Cloud deploys TiKV nodes evenly to all availability zones (at least 3) in the region you select to achieve durability and high availability. In a typical 3-replica setup, your data is distributed evenly among the TiKV nodes across all availability zones and is persisted to the disk of each TiKV node.
TiFlash node
TiFlash(https://docs.pingcap.com/tidb/stable/tiflash-overview), as a columnar storage extension of TiKV, is the key component that makes TiDB essentially a Hybrid Transactional/Analytical Processing (HTAP) database. In TiFlash, the columnar replicas are asynchronously replicated according to the Raft Learner consensus algorithm. TiDB Cloud deploys TiFlash nodes evenly to different availability zones in a region. It is recommended that you configure at least two TiFlash nodes in each TiDB Cloud cluster and create at least two replicas of the data for high availability in your production environment.