ClickHouse是俄罗斯的Yandex于2016年开源的列式存储数据库(DBMS),使用C++语言编写,主要用于在线分析处理查询(OLAP),能够使用SQL查询实时生成分析数据报告。 OLAP(On-Line Analytical Processing)翻译为联机分析处理,专注于分析处理,从对数据库操作来看,OLAP是对数据的查询; OLTP(on-line transaction processing)翻译为联机...
Oracle Database maintains tables used for internal processing. When it needs to change these tables, Oracle Database generates an internal SQL statement, which in turn generates a recursive call. In short, recursive calls are basically SQL performed on behalf of your SQL. So, if you had to p...
Oracle Database generates an internal SQL statement, which in turn generates a recursive call. In short, recursive calls are basically SQL performed on behalf of your SQL. So, if you had to parse the query, for example, you might have had to run some other queries to get ...
CJQ0 typically handles job queues for the older DBMS_JOB framework but also plays a part in the execution of DBMS_SCHEDULER jobs by managing the job queue and distributing jobs to job slaves (Jnnn processes) for execution. CQJ0 is related to job scheduling, specifically for Oracle's Scheduler...
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 | ...
projection VARCHAR(4000), special_predicates VARCHAR(4000), time INT, qblock_name VARCHAR(128), other_xml VARCHAR(4000)); Query OK, 0 rows affected obclient> CREATE TABLE t1(c1 INT); Query OK, 0 rows affected /* Explain an SQL query and store the obtained execution plan in the test ...
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); ...
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 | ...
suppressed options COST and BYTES The Note Section In addition to the plan and the predicate information, the DBMS_XPLAN package displays additional information in the NOTE section, such as when dynamic sampling was used during query optimization or that star transformation was applied to the query...
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| ---...