author_bio, CA.id as co_author_id, CA.username as co_author_username, CA.password as co_author_password, CA.email as co_author_email, CA.bio as from Blog B left outer join Author A on B.author_id = A.id left outer join Author CA on B.co_author_id = CA.id where B.id = #{id} Recall that the resultMap for Author is defined as

j0302p0000702a83116fcee83f70419ca5e2993791 | sharding_db | t_order | 1 | true | 2023-10-27 22:01:27 | (1 row) 2. View the details of the CDC task SHOW STREAMING STATUS j0302p0000702a83116fcee83f70419ca5e2993791; Running Running result sharding_db=> SHOW STREAMING STATUS j0302p0000702a83116fcee83f70419ca5e2993791; item | data_source | status | active | processed_records_count | inventory_finished_percentage | incremental_idle_seconds 5/597E4450 | 5/ 597E4810 | (2 rows) 3. Drop CDC task DROP STREAMING j0302p0000702a83116fcee83f70419ca5e2993791; The CDC task can only be deleted when there are no subscriptions. At this time, the replication

and is also one of the databases’core technologies. ShardingSphere provides distributed transaction ca‐ pability on top of a single database, which can achieve data security across underlying data sources port • SELECT/UPDATE/DELETE 3.9. Shadow 49 Apache ShardingSphere document, v5.2.0 • condition ca tegories* SQL • support or not* = SELECT/UPDATE/DELETE ⋯ WHERE column = value support LIKE/NOT oth‐ erwise, each read traffic is routed to a different replica using random strategy FIXED_REPLI CA_ROUND_ROBIN Open transaction displayed, and the read query is routed to a fixed replica using round‐robin

j0302p0000702a83116fcee83f70419ca5e2993791 | sharding_db | t_order | 1 | true | 2023-10-27 22:01:27 | (1 row) 2. 查看 CDC 任务详情 SHOW STREAMING STATUS j0302p0000702a83116fcee83f70419ca5e2993791; 运行结果 sharding_db=> sharding_db=> SHOW STREAMING STATUS j0302p0000702a83116fcee83f70419ca5e2993791; item | data_source | status | active | processed_records_count | inventory_finished_percentage | incremental_idle_seconds | confirmed_position j0302p0000702a83116fcee83f70419ca5e2993791; 只有当 CDC 任务没有订阅的时候才可以删除，此时也会删除 openGauss 物理库上的 replication slots sharding_db=> DROP STREAMING j0302p0000702a83116fcee83f70419ca5e2993791; SUCCESS 注意事项 增量数据推送的说明

column1 from table1 where column1 = value1 do not sup‐ port • SELECT/UPDATE/DELETE • condition ca tegories* SQL • support or not* = SELECT/UPDATE/DELETE ⋯ WHERE column = value support LIKE/NOT rith m.lo adba lanc e.Tr ansa ctio nWei ghtR eadQ uery Load Bala nceA lgor ithm FI XED _RE PLI CA_ RAN DOM Open transaction, and the read request is routed to a fixed replica using a random strategy; loa dbal ance .Fix edRe plic aRou ndRo binR eadQ uery Load Bala nceA lgor ithm FI XED _RE PLI CA_ WEI GHT Open transaction, and the read request is routed to a fixed replica using a weight strategy;

“jbosst s”,“host”=“127.0.0.1”))) ALTER SQL_PARSER RULE SQL_ COMMENT_PARSE_ENABLE=xx, PARSE_TREE_CA CHE(INITIAL_CAPACITY=xx, MAXIMUM_SIZE=xx, CON‐ CURRENCY_LEVEL=xx), SQL_STATEMENT_CAC HE(INITIAL_CAPACITY=xxx SQL_PARSER RULE SQL_COM MENT_PARSE_ENABLE=false, PARSE_TREE_CA CHE(INITIAL_CAPACITY=10, MAXIMUM_SIZE=11, CON‐ CURRENCY_LEVEL=1), SQL_STATEMENT_CA CHE(INITIAL_CAPACITY=11, MAXIMUM_SIZE=11, CONCUR‐ RENCY_LEVEL=100)

REPLICA_RANDOM 显示开启事务，读请求采用随机 策略路由到一个固定 repl ica；不 开事务，每次读流量使用随机策 略路由到不同的 replica FIXED_REPLI CA_ROUND_ROBIN 显示开启事务，读请求采用轮询 策略路由到一个固定 repl ica；不 开事务，每次读流量使用轮询策 略路由到不同的 replica FIXED_ REPLICA_WEIGHT dwritesplitting.algor ithm.loadbalance.Tran sac‐ tionWeightReadQuer yLoad‐ BalanceAlgorithm FI XED_REPLI CA_RANDOM 显示开启事务，读请求采用随机 策略路由到一个固定读库；不开 事务，每次读流量使用指定算法 路由到不同的读库 org.apach e.shardingsphere.read ting.algorithm. load‐ balance.FixedRepl icaRoundRobinReadQuer yLoadBalanceAlgorithm FI XED_REPLI CA_WEIGHT 显示开启事务，读请求采用权重 策略路由到多个读库；不开事务， 每次读流量使用指定算法路由 到不同的读库 org.apach e.shardingsphere.read writesplitting

“jbosst s”,“host”=“127.0.0.1”))) ALTER SQL_PARSER RULE SQL_ COMMENT_PARSE_ENABLE=xx, PARSE_TREE_CA CHE(INITIAL_CAPACITY=xx, MAXIMUM_SIZE=xx, CON‐ CURRENCY_LEVEL=xx), SQL_STATEMENT_CAC HE(INITIAL_CAPACITY=xxx SQL_PARSER RULE SQL_COM MENT_PARSE_ENABLE=false, PARSE_TREE_CA CHE(INITIAL_CAPACITY=10, MAXIMUM_SIZE=11, CON‐ CURRENCY_LEVEL=1), SQL_STATEMENT_CA CHE(INITIAL_CAPACITY=11, MAXIMUM_SIZE=11, CONCUR‐ RENCY_LEVEL=100)

“jbosst s”,“host”=“127.0.0.1”))) ALTER SQL_PARSER RULE SQL_ COMMENT_PARSE_ENABLE=xx, PARSE_TREE_CA CHE(INITIAL_CAPACITY=xx, MAXIMUM_SIZE=xx, CON‐ CURRENCY_LEVEL=xx), SQL_STATEMENT_CAC HE(INITIAL_CAPACITY=xxx SQL_PARSER RULE SQL_COM MENT_PARSE_ENABLE=false, PARSE_TREE_CA CHE(INITIAL_CAPACITY=10, MAXIMUM_SIZE=11, CON‐ CURRENCY_LEVEL=1), SQL_STATEMENT_CA CHE(INITIAL_CAPACITY=11, MAXIMUM_SIZE=11, CONCUR‐ RENCY_LEVEL=100)

effective. • Dynamic configuration: distribution after configuration modification is another important ca‐ pability of configuration center. It can support dynamic switch between data sources and rule configurations