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 数据库schema clickhouse...
DBMS_XPLAN.DISPLAY table function This function accepts options for displaying the plan table output. You can specify: A plan table name if you are using a table different than PLAN_TABLE A statement ID if you have set a statement ID with the EXPLAIN PLAN A format option that determines...
獲得SQL的執行計劃是對SQL進行最佳化的第一步,然而使用“explain plan for”方法又是一個最基本的獲得執行計劃的手段,當然,您也可以選擇使用autotrace和sql_trace等工具獲得SQL的執行計劃。 在使用explain plan for方法得到SQL執行計劃的過程中,要頻繁的使用“select * from table(dbms_xplan.display());”語句檢視...
BASELINE_PLAN_NAME1 VARCHAR2IN BASELINE_PLAN_NAME2 VARCHAR2IN FUNCTIONDISPLAYRETURNSDBMS_XPLAN_TYPE_TABLE 引數名稱 型別 輸入/輸出預設值? --- TABLE_NAMEVARCHAR2INDEFAULT STATEMENT_ID VARCHAR2INDEFAULT FORMAT VARCHAR2INDEFAULT FILTER_PREDS VARCHAR2INDEFAULT FUNCTIONDISPLAY_AWRRETURNSDBMS_XPLAN_TYPE_TA...
statement and then look for this hash value in the library cache. This access path will be used until the query is re-parsed. Terminology ~~~ Row Source - A row source is a software function that implements specific operations (such as a table scan or a hash join) and returns ...
which is a hash join rowsource, and so on. Note that os_explain prefixes some lines with an asterisk (*), this indicates that the output of given function is in turn filtered by a filter operation (the same filter ops what you normally see in the bottom of DBMS...