Original Post can be viewed at portmap: unrecognized service on RHEL6
Quick note for people using NFS for shared storage on RAC database. Till RHEL5 we had to ensure nfs,nfslock and portmap service has to be running. These services are required otherwise you will get following errors while mounting database (more...)
A new major release (version 3.0) of my XPLAN_ASH tool is available for download.You can download the latest version here.
In addition to many changes to the way the information is presented and many other smaller changes to functionality there is one major new feature: XPLAN_ASH now also supports S-ASH
, the free ASH implementation.
If you run XPLAN_ASH in a S-ASH repository owner schema, it will automatically detect that and adjust accordingly. (more...)
Original Post can be viewed at cursor: pin S wait on X
Few weeks back thread came up on oracle-l freelist regarding ”cursor: pin S wait on X” event . Tanel Poder replied to this thread with excellent explanation. You can read full thread here
This wait happens when your (more...)
Install the Oracle Database Gateways 11g R2 (11.2). See the screen snapshots of the installation here.
- During the installation, the following default initialization parameter file is created:
dg4msql = Database gateway for Microsoft SQL Server.
If you choose a different database option, (more...)
Attention all data modellers - we are pleased to announce the release of SQL Developer Data Modeler 3.3. This release includes a new search, reports can be generated from search results, extended Excel import and export capabilities and more control and flexibility in generating your (more...)
In the previous post
I've demonstrated an unexpected Nested Loop Join caused by an extreme data distribution. Although unexpected at first sight, the performance of the execution plan selected by the optimizer is decent - provided the estimates are in the right ballpark.Here is another case of an unexpected execution plan, this time about Merge Joins
In order to appreciate why the execution plan encountered is unexpected, first a quick summary about (more...)
Recently I came across some interesting edge cases regarding the costing of joins. They all have in common that they result in (at first sight) unexpected execution plans, but only some of them are actual threats to performance.
The first one is about outer joins
with an extreme data distribution. Consider the following data setup:
create table t1
rownum as id
, rpad('x', 100) as filler
, case when rownum > (more...)
Oracle 10g introduced the QB_NAME
hint that can come handy in case hints need to be applied to more complex statements, in particular when possibly multiple layers of views / subqueries are involved.Jonathan Lewis has a older blog post
that describes more details.Just in case you wonder why sometimes apparently the QB_NAME
hint - along with all other hints that refer to the assigned query block name - seems to be ignored: One (more...)
See the blog post over at Oracle for details, and be sure to send Christopher Jones an email (via the address in his post) stating you're an active user of the client. As Christopher mentions in his post,
You can really help us justify resources for the OS X bundle if you email me letting me know you are a fan. Since Instant Client is a free download, it is tricky for us to know how widely it gets used.
Jump to OTN to download, but please remember to email Christopher as well, if you're interested in seeing the client (more...)
Original Post can be viewed at 11.2 AQ – Messages stuck in PROCESESED,WAIT State
I had been working today on AQ issue where messages were not moving from WAIT to READY State.This was on 18.104.22.168 database running on RHEL5u6(64 bit). I thought of quickly documenting it for easy reference When you enqueue record, you can specify delay after which record should be ready for dequeue. During this time, MSG_STATE [...]
Original Post can be viewed at Using SQL commands on ADRCI
While working with ADRCI , I came to know that we can run normal SQL commands for some of the operation.e.g To display current purge policy , you can run select * from adr_control instead of show control. adrci> desc ADR_CONTROL Name Type NULL? ----------------------------- --------------- ----------- ADRID number SHORTP_POLICY number LONGP_POLICY number LAST_MOD_TIME timestamp [...]
[I originally posted this over at the Pythian blog. If you're not following it, you should! Way more content, by far smarter people than lil ol' me.]
After reviewing my blog post about running EBS OVM templates in VirtualBox, two of my teammates suggested that I work on something with potentially broader appeal. Their basic message was, "This is really cool for us EBS nerds, but what about the Core DBAs?"
So how does "11gR2 RAC in an hour" sound? In this post, I'll demonstrate how to deploy the pre-built Oracle VM templates to create a two-node (more...)
Original Post can be viewed at Limiting I/O and CPU resources using 11g Oracle Resource Manager
Recently I was working on using Oracle DBMS_RESOURCE_MANAGER to limit resources usage by read-only queries. This was required to prevent long running ad-hoc and poorly written queries.Instead of writing custom sql /script to kill long running session, we decided to utilize Oracle Database Resource Manager. We decided using elapsed_time as criteria for cancelling sql.But during [...]
Original Post can be viewed at ORA-12514 due to DNS issue
A User reported ORA-12514 error from JDBC application connecting to RAC database ORA-12514: TNS:listener does not currently know of service requested in connect descriptor To troubleshoot it, a)I checked following things to ensure specified service is running srvctl status service -d dbname -s serv_name b) Ensured service is registered with listener lsnrctl status Note that [...]
Original Post can be viewed at Sqlplus HTML reports
I was working on setting up monitoring for application team to monitor AQ and wanted html formatting of table data. On searching I found this link from Ittichai Chammavanijakul which makes use of css formatting to generate good visual reports. EMPNO ENAME JOB MGR HIREDATE SAL COMM DEPTNO 7369 SMITH CLERK 7902 17-DEC-1980 00:00:00 800 [...]
Gone are the day when cleartext passwords had to be stored in scripts for Oracle database access. The solution to this requirement is “Oracle Secure External Password Store (SEPS)”. This article will give a short introduction and a practical example of the solution.
no Advanced Security Option (License) necessary
every unix-account, who has access to the wallet can use it to log on to the contained databases without a password! Therefore prevent other unix-accounts from accessing your wallet! (chmod, chown)
: Unix-Account, who wishes to connect to the database without providing a password needs to (more...)