为了避免执行同一条SQL每次都要解析、校验、优化器等操作,PolarDB-X内置了PlanCache,会在PlanCache中获取该SQL的执行计划,当然,并不是根据纯字符串SQL来进行缓存,而是生成SqlParameterized,如下图所示(Planner#plan),真正缓存的是sql模板,该类中的sql变量:INSERT INTO sbtest (id)\nVALUES (?),可适用于类似的语...
为了避免执行同一条SQL每次都要解析、校验、优化器等操作,PolarDB-X内置了PlanCache,会在PlanCache中获取该SQL的执行计划,当然,并不是根据纯字符串SQL来进行缓存,而是生成SqlParameterized,如下图所示(Planner#plan),真正缓存的是sql模板,该类中的sql变量:INSERT INTO sbtest (id)\nVALUES (?),可适用于类似的语...
所以在优化器阶段,我们会根据 Unique Key 是在主表还是 GSI 上定义的来确定相应的 SELECT 需要发送到主表还是 GSI,具体代码位置: com.alibaba.polardbx.optimizer.core.planner.rule.OptimizeLogicalInsertRule#groupUkByTable protected Map<String, List<List<String>>> groupUkByTable(LogicalInsertIgnore insertIgnor...
为了避免执行同一条SQL每次都要解析、校验、优化器等操作,PolarDB-X内置了PlanCache,会在PlanCache中获取该SQL的执行计划,当然,并不是根据纯字符串SQL来进行缓存,而是生成SqlParameterized,如下图所示(Planner#plan),真正缓存的是sql模板,该类中的sql变量:INSERT INTO sbtest (id)\nVALUES (?),可适用于类似的语...
sabot/kernel/src/main/java/com/dremio/exec/planner/sql/handlers/commands/CommandCreator.java https://docs.dremio.com/current/sonar/data-sources/object/s3/#advanced-options https://docs.dremio.com/current/reference/sql/commands/tables https://docs.dremio.com/current/reference/sql/commands/apache-ice...
LIKELY(X) Provides a hint to the query planner that argument X is a Boolean value that is usually true. The planner can prioritize filters on the value X earlier in the execution cycle and return results more efficiently. UNLIKELY(X) Provides a hint to the query planner that argument X is...
sabot/kernel/src/main/java/com/dremio/exec/planner/sql/handlers/commands/CommandCreator.java https://docs.dremio.com/current/sonar/data-sources/object/s3/#advanced-options https://docs.dremio.com/current/reference/sql/commands/tables https://docs.dremio.com/current/reference/sql/commands/apache-ice...
所以在优化器阶段,我们会根据 Unique Key 是在主表还是 GSI 上定义的来确定相应的 SELECT 需要发送到主表还是 GSI,具体代码位置:com.alibaba.polardbx.optimizer.core.planner.rule.OptimizeLogicalInsertRule#groupUkByTableprotected Map<String, List<List<String>>> groupUkByTable(LogicalInsertIgnore insertIgnore,...
Subsequently, the query planner uses these statistics to help determine the most efficient execution plans for queries. For more information, see ANALYZE in the PostgreSQL documentation.In Aurora PostgreSQL Limitless Database, the ANALYZE command collects table statistics across all routers and shards ...
com.alibaba.polardbx.optimizer.core.planner.rule.OptimizeLogicalInsertRule#groupUkByTable protectedMap<String,List<List<String>>>groupUkByTable(LogicalInsertIgnore insertIgnore, ExecutionContext executionContext) {// 找到每个 Unique Key 在主表和哪些 GSI 中存在Map<Integer,List<String>> ukAllTableMap =...