What are the performance differences between PostgreSQL and SQL server? Compare the performance of PostgreSQL vs. MSSQL 中文:两种数据库在性能上的差异 PostgreSQL提供在各种数据集大小上的速度和性能,并且通常在在线事务处理(OLTP)和在线分析处理(OLAP)速度方面胜过其他数据库。它提供了多版本并发控制(MVCC),允许...
以下是整理出的一些数据库规划、SQL performance tuning 简单心得,让长年钻研 .NET、AJAX、一堆高深 ooxx framework,却无暇研究 SQL statement 的程序员,透过最短时间对本文的阅读,能避免踩到一些 SQL 的性能地雷。 1、数据库设计与规划 ? Primary Key 字段的长度尽量小,能用 small integer 就不要用 integer。例...
语句级事件(sql_statement_completed、sql_statement_starting、sp_statement_starting、sp_statement_completed) 登录和注销事件(login、process_login_finish、login_event、logout) 锁定事件(lock_acquired、lock_cancel、lock_released) 等待事件(wait_info、wait_info_external) ...
顶层节点Executor,BaseExecutor中使用了一级缓存PerpetualCache,一共有四个子类,类图中还没标全,分别是SimpleExecutor简单执行器、ReuseExecutor可重用执行器(重用同一个Statement对象)、BatchExecutor批处理执行器、ClosedExecutor关闭的执行器(ResultLoaderMap的内部类,用于标记序列化反序列化后执行器处于关闭状态)。CachingExe...
Full Optimize还分 Search 0, Search 1, Search 2. Simplification 简单来讲概念就是去重,比如有where条件了,就不用Foreign Key约束,或者join的时候,提前将where条件放到join里面去做限制以减少数据集;Trivial Plan就是不经历full optimize 直接产生执行计划,这里要注意的执行计划属性StatementOptmLevel, 走Trivial Plan...
ADD EVENT sqlserver.module_end(SET collect_statement=(1) ACTION(package0.event_sequence,sqlserver.client_app_name,sqlserver.database_id,sqlserver.plan_handle,sqlserver.query_hash,sqlserver.query_plan_hash,sqlserver.session_id,sqlserver.sql_text,sqlserver.tsql_frame,sqlserver.tsql_stack) WHERE ([packag...
We regularly insert data into SQL Server tables either from an application or directly in SSMS. We can insert data using the INSERT INTO statement. To do this, we should have a table already in place to insert data into it as we cannot create a table using Insert into the statement. ...
The Oracle optimizer determines the most efficient execution plan and is the most important step in the processing of any SQL statement. The optimizer: • Evaluates expressions and conditions • Uses object and system statistics • Decides how to access the data ...
sql_statement_recompile扩展事件 (XEvent) 报告语句级重新编译。 当任何类型的批处理需要语句级重新编译时,会发生此 XEvent。 这包括存储过程、触发器、即席批处理和查询。 可通过几个接口来提交批处理,这类接口包括 sp_executesql、动态 SQL、“准备”方法或“执行”方法。
There are many ways to improve SQL performance, including: Multiple joins in a single query should be avoided. A set-based query should be used instead of a cursor-based query. Non-correlated scalar sub-queries should be avoided in standard queries. Multi-statement Table Valued Functions (TV...