oracle sql performance analyzer

optimizes full table scan by reading multiple data blocks at a time.B. Access the table through rowidYou can use rowid-based access to improve table access efficiency ,,Rowid contains the physical location information recorded in the Table. Oracle uses indexes to establish a connection between the physical location (rowid) of the data and the physical location (rowid) of the data.Generally, indexes provide a quick way to access rowid, so those querie

Absrtact: The development of dynamic SQL program is summarized, and some development techniques are given according to the author's actual development experience. Key words: Dynamic Sql,pl/sql, high performance 1. static sqlsql and dynamic SQL

The ORACLE tutorial is: Oracle SQL Performance Optimization Series 2. 4. Select the most efficient table name sequence (only valid in the rule-based Optimizer) The ORACLE parser processes the table names in the FROM clause in the order FROM right to left. Therefore, the tab

a simple lexical analyzer to break SQL statements into multiple tokens. For the syntax analysis from token and SQL AST construction, I have no experience at the moment (the compilation principle is too bad), and I am in urgent need of help. So here is a brief introduction to the lexical analysis of mixer. Tokenize In many places, we need to perform lexical analy

itself, or view the actual plan after the query is executed. Obviously, the real plan is more accurate because it is physically running the query on the database. However, this approach may not be the best choice for a large and/or long-term system load query. In a typical case, I run this tool when I think a particular query is having a problem, or if I expect a query to be called frequently enough in the application so that it can cause performance

1. The question The system has a module that needs to query the data in the Oracle database. It is now implemented by establishing a linked server. SQL Server access Oracle implementation can refer to this article http://www.cnblogs.com/gnielee/archive/2010/09/07/access-oracle-from-sqlserver.html The current query s

The ORACLE tutorial is: Oracle SQL Performance Optimization Series 2.4. Select the most efficient table name sequence (only valid in the rule-based Optimizer)The ORACLE parser processes the table names in the FROM clause in the order FROM right to left. Therefore, the table

oracle| Performance | optimization 36. Replace or with union (applicable to indexed columns) In general, replacing or in a WHERE clause with union would have a better effect. Using or for an indexed column causes a full table scan. Note that the above rules are valid only for multiple indexed columns. If a column is not indexed, query efficiency may be reduced because you have not selected an OR. In the f

Tags: sum statement oracle nbsp SQL statement monitor best dia user--oracle Common Performance Monitoring SQL statements--1SELECT * from SYS. V_$sqlarea WHERE disk_reads > 100; --2 waiting for the monitoring caseSELECT EVENT,SUM (DECODE (wait_time, 0, 0, 1)) "Prev",SUM (DECO

oracle| Performance | optimization 43. Where to replace the order by The ORDER BY clause uses the index only under two strict conditions. All columns in the order by must be contained in the same index and remain in the index. All columns in the order by must be defined as non-null. The index used in the WHERE clause and the index used in the ORDER BY clause cannot be tied. For example: The tabl

In the absence of visual tools to monitor database performance, common scripts come in handy. Below are a few scripts related to Oracle performance for your reference. The following scripts are successfully tested in Oracle 10 Gb, and Oracle 11 GB may be adjusted accordingly

The following articles mainly talk about Oracle Performance Check SQL statements. On a website with good reputation, I found a reference to Oracle Performance Check SQL statements and related code examples, to share with you. The

the query executes. It is clear that the real plan will be more accurate because it is physically running queries against the database. However, this approach may not be the best option for systems with large load and/or long-term queries. In a typical case, I run this tool when I think there is a problem with a particular query, or if I expect a query to be called frequently enough in the application to cause performance problems. You can view the e

))/1000000,2) as Cpu_time,round ((N.CPU_TIME-NVL (o.cpu_time,0))/(( N.EXECUTIONS-NVL (o.executions,0)) *1000000), 2) as Cpu_time_per_exe,round ((N.ELAPSED_TIME-NVL (o.elapsed_time,0))/( (N.EXECUTIONS-NVL (o.executions,0)) *1000000), 2) as Elapsed_time_per_exe "+"From" +newtable+ "n" +"Left JOIN" +oldtable+ "o o.hash_value = n.hash_value and o.address = n.address" +"WHERE n.last_active_time > To_date ('" + sysdate + "', ' yyyy/mm/dd hh24:mi:ss ')" +"and (N.EXECUTIONS-NVL (o.executions,0)) > 0" +"