查看sql执行计划explainplan for需要调试sql例如:Select* from abc; select* from table(dbms_xplan.display...把多段UNION ALL 拆分开来分开执行,找到变慢的一段sql. 2.把查询字段减少为一个,排除字段多导致缓慢. 3.对比执行计划,发现问题,2018年的执行了笛卡尔连接MERGE JOIN ...
This is how many blocks you processed in "consistent read" mode. This will include counts of blocks read from the rollback segment in order to roll back a block. This is the mode you read blocks in with a SELECT, for example. Also, when you do a searched UPDATE/DELETE, you read the...
This is how many blocks you processed in "consistent read" mode. This will include counts of blocks read from the rollback segment in order to roll back a block. This is the mode you read blocks in with a SELECT, for example. Also, when you do a searched UPDATE/DELETE, you read the...
This is how many blocks you processed in "consistent read" mode. This will include counts of blocks read from the rollback segment in order to roll back a block. This is the mode you read blocks in with a SELECT, for example. Also, when you do a searched UPDATE/DELETE, you read the...
SQL>SELECT plan_table_output FROM TABLE(DBMS_XPLAN.DISPLAY('PLAN_TABLE')); 示例: SQL>EXPLAIN PLAN FOR SELECT * FROM DAVE; 已解释。 SQL>SELECT plan_table_output FROM TABLE(DBMS_XPLAN.DISPLAY('PLAN_TABLE')); 或者: SQL>select * from table(dbms_xplan.display); ...
up to deal with.For example: Ok, got it OceanBase Data V4.2.1 What is OceanBase Database Get Started Develop Deploy Migrate Manage OBKV Reference System principles System management Database object management Database design
SQL>SELECT plan_table_output FROM TABLE(DBMS_XPLAN.DISPLAY('PLAN_TABLE')); 或者: SQL>select * from table(dbms_xplan.display); PLAN_TABLE_OUTPUT --- Plan hash value: 3458767806 --- | Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | ...
The example in Figure 5 displays the basic execution plan and includes information on any predicates as well as the Optimizer Cost column. SELECT plan_table_output FROM TABLE(DBMS_XPLAN.DISPLAY('plan_table',null,'basic +predicate +cost')); Figure 5: Customized BASIC plan output with selected...
Given below are the examples to see the implementation of the EXPLAIN command with SQL queries: Example #1 We will firstly consider the query statement in SQL which will retrieve the values of the columns named Article_id and Article_name from Educba_articles table and the information of writer...
ClickHouse是一个用于"联机分析"(OLAP)的列式数据库管理系统(DBMS:Database Managerment System),简称CH ,主要用于 “在线分析处理查询”(OLAP:Online Analytical Processing),能够使用SQL查询"实时生成分析"数据报告 . ClickHouse clickhouse数据库 aes加密 大数据 数据库 数据 服务器 clickhouse属于nosql clickhouse支持...