by index

Before describing their differences, let's take a look at the memory model of the Data zone during JVM runtime.In the deep Java Virtual Machine (VM) book, The Memory Model of the JVM runtime data zone is composed of five parts: [1] Method Area[2]

  RTCPRRPacket ----------------------------------------------------------------------- Header file: rtcprrpacket. h ---------------------------------------------------------------------- Inherited from: RTCPPacket Class describes an RTCP receiver

Select case when status = 'unusable' then 'alter Index' | Owner | '. '| index_name | 'rebuild online compute statistics; 'When to_number (degree)> 1 then 'alter index/* '| degree |' */'| Owner | '. '| index_name | 'noparallel;' End casefrom (select *

Select Case when status= ' unusable ' then ' alter index ' | | owner| | '. ' | | index_name| | ' Rebuild online compute statistics; ' When To_number (degree) >1 then ' ALTER INDEX/* ' | | degree | | | owner| | '. ' | |

[Date: 2011-08-05]Source: Linux Community wangshengfeng1986211[Font: Big Small]2010-07-01 15:031. SET AUTOTRACE on EXPLAIN(Set AUTOT on exp)The Sqlplus command, which displays the execution plan while executing the SQL statement, sets exp (lain) to

Switching-Different SQL Plan with SQL profiles in Oracle ... When SQL is generated dynamically by a business system, or is generated by a third-party system, it may be difficult to modify the business program to improve execution plan and

A friend asked me an UPDATE statement, the following two kinds of writing which performance is higher, one is not hint, one is hint UPDATE cs_performance_current C SET c.performance_score = ' 0.00 ', C.assess_desc = ' discipline assessment ' WHERE

When a WHERE clause uses a function for a column, the Oracle optimizer cannot use the index in the query unless this simple technology is used to force the index. Generally, if you do not use functions such as UPPER, REPLACE, or substrd in the where

Oracle official documentation: OracleDatabaseSQLLanguageReference1, orderedhint2, leadinghint3, use_nl1, orderedhint * + ORDERED * handle. Oraclerec Oracle official documentation: oracle Database SQL Language Reference 1, ordered hint 2, leading

The previous examples demonstrate the performance improvement caused by the standard writing of paging query statements. Here, we will briefly describe when paging query statements cannot improve performance. The paging query statement can

Oracle fails to return an index due to an error. There is an Oracle script that has been running for a long time without any results. After optimization, the results are instantly displayed. The original statement is as follows:SQL> explain plan2

The developer sends an SQL statement and generates 236 rows of data at 7 minutes 32 seconds select OT. guest_id, OT. order_id, OT. guest_name, Oct. guest_name, OT. ticket_price, Oct. ticket_price from t_to_order_tickets ot left join (select Oct. *, (

When the system load is high, capture an SQL statement and output 152 rows of select a around 1 minute 23 seconds. case_id,. case_type_id,. case_subject,. case_content,. create_employee_id,. case_create_time,. customer_id,. dept_id,.

In the execution plan development process, the transformation and the choice has this different task; in fact, after a query finishes syntax and permission checks, the first step that is called "query transformation" occurs, where a series of query

Indexing is the most effective way to improve data query and the most difficult technology to master, because correct indexing may increase the efficiency by 10000 times, and invalid indexing may waste database space, the query performance is even

Document directory Application Analysis of indexes in Oracle Application Analysis of indexes in Oracle Indexing is the most effective way to improve data query and the most difficult technology to master, because correct indexing may increase the

Application Analysis of indexes in Databases Index is the most effective way to improve data query and the most difficult technology to master, because correct index may increase the efficiency by 10000 times, but it is invalid This may result in a

Application Analysis of indexes in Databases Indexing is the most effective way to improve data query and the most difficult technology to master, because correct indexing may increase the efficiency by 10000 times, and invalid indexing may

This article mainly introduces the definition and use of Python list and tuple, and analyzes the function, difference, definition and use of the list and tuple in Python in the form of instance, which can be referenced by friends. The examples in

Today, I called an SQL statement, and BITMAPCONVERSION appeared in the execution plan. I checked the index and there was no bitmap index. Today, I called an SQL statement, and bitmap conversion appeared in the execution plan. I checked the index and