DBA Tools

How oramon track Oracle performance? -- V$SESSION

    When hit database load problems, I always want to know what the active sessions are doing and waiting. On 10g we can get these information from V$SESSION view, on 8i and 9i, we can join V$SESSION and V$SESSION_WAIT....

Posted on December 3, 2007 4:45 PM

Fast Oracle text unload speed with ociuldr by Alibaba

    Free Oracle text unload utility (ociuldr) was used to extract Oracle data from OLTP system and then load them into their OLAP system by alibaba company (Taobao). They get a really fast unload speed these days. 0         rows...

Posted on November 29, 2007 8:00 PM

How to improve the performance of Oracle exp/imp?

    A lot of people complain the speed of Oracle exp/imp utility, seems the only thing we can do is to specify large buffer size. Actually there are some other methods to improve the performance a little. For export...

Posted on November 28, 2007 9:32 PM

How oramon track Oracle performance? -- V$SYSSTAT

    Oracle's system level statistics is very useful for performance track. Oracle keep on add new statistics from Oracle 8, 8i, 9i, 10g to 11g. The key is how to display the statistics value. SQL> SELECT name, value FROM...

Posted on November 27, 2007 8:23 PM

Windows explorer runs slowly due to network drives mapping

    My notebook (Dell D630, 2GB memory) runs very well in company, but when I bring it to home, the windows explore runs slowly, and always hang for about one to three seconds. While the other application did not...

Posted on October 16, 2007 8:05 PM

Track Oracle database performance with oramon utility

    I am writing an Oracle performance tracking utility -- oramon. And I have finished the first version of it, to make it more powerful, I compiled a windows version binary for free download. What this utility do is...

Posted on October 15, 2007 10:50 PM

Tuning Oracle SQL performance by rewriting it.

    I got a task to run the following two SQLs in 20 site databases, the table is very big, about 100GB size in every database. So it not a easy task. SELECT /*+ FULL(T) PARALLEL(T,4) */  COUNT(*) FROM BIGTABLE...

Posted on October 11, 2007 10:16 AM

Performance issue by OR operation because filter at table level.

    I create a composite index (DEPTNO and ENAME columns) on table SCOTT.EMP. Then I run the following SQL. SQL> SELECT /*+ first_rows no_expand */ * FROM EMP    2 WHERE deptNO=10 AND (ENAME IS NULL OR ENAME >...

Posted on October 11, 2007 10:00 AM

How to perform bulk delete in PL/SQL for better performance?

    In Pro*C or OCI, we can use an host array as a bind value to submit array operations, it will reduce the network round trips, user calls and execute count, it can greatly improve the performance. In Java...

Posted on October 10, 2007 5:34 PM

How to choose the SIZE and HASHKEYS of hash cluster table?

    Hash cluster table can get much performance improve for equal access, however proper SIZE and HASHKEYS option is required. In OLTP, we always have some tables, the query use equal condition and with unique or very effective index...

Posted on October 10, 2007 5:19 PM

Analyze or DBMS_STATS, choose one but don't mix them

    I am not so familiar with the DBMS_STATS procedure, so I always use the "ANALYZE" command. One day I got the following problem. Let's start a demo, first step is creating demo partitioned table. SQL> CREATE TABLE T_PARTDEMO(...

Posted on September 29, 2007 12:37 PM

High performance tuning for Oracle SQL Loader

    To get the maximum performance of Oracle SQL Loader (sqlldr), take the following into account.     Use fixed width column text file such as following. 10 ACCOUNTING   NEW YORK 20 RESEARCH     DALLAS 30 SALES        CHICAGO 40 OPERATIONS   BOSTON      ...

Posted on September 15, 2007 5:19 PM

High performance for Oracle text unload or export with ociuldr

    ociuldr (Source) is a free utility used to unload Oracle rows to text file, which can be used to prepare data for data warehouse, or do the data migration from Oracle to other databases, or moving data between...

Posted on September 11, 2007 7:32 PM

Tuning the performance of data replication with asyncdata

    Performance is critical for OLTP system, asyncdata should have good performance for the data replication, else it may not be able to catch up with the source table. Following is the key points to get the best performance....

Posted on September 10, 2007 10:53 PM