mevo plan

6 ways to get the execution plan (detailed steps have been explained in the comments section at the beginning of each example):1. Explain plan for acquisition;2. Set autotrace on;3. Statistics_level=all;4. Direct access via Dbms_xplan.display_cursor input sql_id parameters5.10046 Trace Trace6. Awrsqrpt.sqlTwo. Applicable occasions analysis1. If a SQL executes for a very long time to produce results, even if

Tags: interpreting mode reference log Mys join useful SQL wwwLeft Join Left join in no brain use, will be large table drive small table, trigger Cartesian set, slow efficiency Join will auto small table drive Large table Reference: Deepen your understanding of query plans from an example of MySQL left join optimizationhttp://luxuryzh.iteye.com/blog/1976004 Related explain query plan explanation Type is divided into several categories, such as system/

Text: Third--Part II--the second article plan to build SQL Server mirroringThis article follows the previous chapter: Introduction to SQL Server mirroringThe source of this article: http://blog.csdn.net/dba_huangzj/article/details/27203053As the saying goes: 工欲善其事 its prerequisite. Planning how to deploy and use mirroring can reduce a lot of unnecessary risk. This article will be presented in the form of three steps, but be aware that this is not the

Database environment: SQL SERVER 2005Today I see a SQL, not very complicated to write, returned more than 7,000 data, but executed 15s. The amount of data in SQL text and tables is as follows:SELECTAcinv_07.id_item,SUM(acinv_07.dec_endqty) Dec_endqty fromacinv_07WHEREAcinv_07.fiscal_year* - +Acinv_07.fiscal_period=(SELECT DISTINCTCtlm1101.fiscal_year * - +Ctlm1101.fiscal_period fromctlm1101 WHEREFlag_curr= 'Y'

When SQL server receives any command, including query, batch processing, stored procedures, triggers, pre-compiled commands, and dynamic SQL Server statements, it must complete Syntax Parsing and semantic analysis, then, compile the program to generate an executable plan ". During compilation, SQL Server estimates possible execution plans and their costs based on the architecture, statistics, and specific instructions of the objects involved, finally,

As the saying goes: Everything pre-standing, not pre-waste! Software Testing in the same way, at the beginning of the test project to develop a corresponding test plan . Next talk about how to write a test plan.A Here are a few things to know first:1. Why write a test plan?1) The leader can do macro-adjustment according to the test plan, and allocate the correspo

my opinion of preparing lesson and teaching plan 1. The relationship between preparing lessons and writing lesson plans The concept of "lesson preparation" and "lesson plan" have long existed the different connotation and extension of the broad and narrow sense in teaching practice: 1, broadly speaking, teachers ' learning and life should be part of the process of preparing lessons, because teachers are als

The first part: Concept ******************************************** SQL Plan management is a new feature introduced with Oracle Database 11g that enables the system to automate the evolution of SQL plans by maintaining so-called "SQL Plan Baseline (11g)". When this feature is enabled, this integration can be done as long as it proves that the newly generated SQL plan