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Datamarts/Datawarehouse performance issues can be scaring events, taking into account the massive amount of data they handle; the tuning task is even more daunting if they're used for operational day-to-day decision making.
During the last week and days, I've been involved on a 15 Tb datamart with performance issues on dataloading, not querying. Tablespaces for indexes and data share filesystems, nowadays this is not a concern anymore, however I prefer to encourage customers to allocate independent storage for each type, that way they are able to discriminate the source of IO.
They have concurrent schedules (more...)
So you're working with Discoverer 10g integrated with the Oracle eBusiness Suite on Release 12. You've installed and set everything up per Metalink/MOS Note 373634.1 "Using Discoverer 10.1.2 with Oracle E-Business Suite Release 12" plus created a custom application and responsibility to have it's own menu items corresponding to your Discoverer Workbooks/Worksheets.
You login to your new responsibility and click on your new menu entry that you created per Metalink/MOS Note "How to Create a Link to a Discoverer Workbook in Apps R12" and what do you get when you query subledger data such as Payables Invoices, (more...)
Recently, my client deployed a new application and had this intermittent “Deadlock Storm” …
A trace file was sent and I was able to pinpoint the cause of the deadlock and the session that caused it.
The deadlock was a TX enqueue with mode of 4 (S – share) which could be verified by looking at the following lines of the Process State dump:
last wait for 'enq: TX - row lock contention' blocking sess=0x 7000000cb239d60 seq=7849 wait_time=2929705 seconds since wait started=3
name|mode=54580004, usn<<16 | slot=a0028, sequence=283f2
the “enqueue and lock mode” is explained as:
mode=54580004 (see above)
5458 (hex) (more...)
Last week, one of our clients had a sudden slow down on all of their applications which is running on two node RAC environment
Below is the summary of the setup:
- Server and Storage: SunFire X4200 with LUNs on EMC CX300
- OS: RHEL 4.3 ES
- Oracle 10.2.0.3 (database and clusterware)
- Database Files, Flash Recovery Area, OCR, and Voting disk are located on OCFS2 filesystems
- Application: Forms and Reports (6i and also lower)
As per the DBA, the workload on the database was normal and there were no changes on the RAC (more...)
Recently I encountered a performance problem scenario where a simple sqlplus “/ as sysdba” took about 2minutes to finish, this is critical to the client’s business because they have a local C program that loads Call Detail Reports on the database making use of local authentication for most of its operations and Sql*Loader to load the data, so this “2minutes of waiting” when accumulated greatly consumes significant time on their operations and greatly impacts the business.
When I arrived on the client I first checked the alert logs of both ASM (they have a separate home for ASM) and RDBMS, (more...)
- Networking and evaluations
Today was the first day of the second Miracle Masterclass this year: Tanel Põder has come to The Netherlands, saw a room filled with a lot of people (he called it the best seminar even before he started, just because of the amount of attendants) and made me feel I have an awful lot to explore yet. However, that is in fact a good thing and it made me get through the “trains nightmare” today with a smile: I had trouble in the morning since I left home far too late, had to cycle as fast as I (more...)