At my current client site, I use AIX on IBM PowerPC kit. There is a neat little systems monitoring tool called “nmon” on AIX, which I quite like. I noticed recently that it’s available on Linux now, so I installed it on my machine, which runs Fedora 12. There are a number of binaries prebuilt, [...]
Archive of posts tagged tuning
No pruning for MIN/MAX of partition key column
Recently, I wanted to work out the maximum value of a column on a partitioned table. The column I wanted the maximum value for, happened to be the (single and only) partition key column. The table in question was range partitioned on this single key column, into monthly partitions for 2009, with data in all [...]
TPC-H Query 20 and optimizer_dynamic_sampling
I was working with Jason Garforth today on creating a TPC-H benchmark script which we can run on our warehouse to initially get a baseline of performance, and then, from time to time, rerun it to ensure things are still running with a comparable performance level. This activity was on our new warehouse platform of [...]
Scripts for loading up DBGEN TPC-H data
If you’re interested in creating a TPC-H schema for testing purposes, then the following scripts may be of use to you: Unix Scripts:Multi Load TPCHLoad TPCH Stream SQL*Loader Control files:REGION TableNATION TableSUPPLIER TableCUSTOMER TablePART TablePARTSUPP TableORDERS TableLINEITEM Table You may wish to read and check them before you use them – they’re not exactly rocket [...]
Creating a TPC-H schema with DBGEN on HP-UX
I wanted to try out this HammerOra product from Steve Shaw, both at work and on my box at home…but after playing with it at home, I realised that it takes quite some time to build even a small (scale factor 1) TPC-H schema…I know it runs serially, but I’m still not quite sure why [...]
Problem with _gby_hash_aggregation_enabled parameter
Here’s a tale about an Oracle initialisation parameter…and a lesson we should all take note of… For three days, my colleagues in the support team on one of the warehouses I’m involved in, were struggling with a piece of code which was exhausting the available temp space and after trying everything they could think of, [...]
CALIBRATE_IO Poll
After Doug’s comment on my earlier blog on CALIBRATE_IO, and after seeing Kevin using Mr Poll to do a RAC poll, I’ve now created a poll for the results people are getting from this CALIBRATE_IO routine in 11g. If you’d like to contribute please visit using the following link: Oracle 11g CALIBRATE_IO Results No prizes [...]
11g IO Calibration tool
After reading how inadequate Doug was feeling over his IO subsystem, I decided to see how quick mine was…not that we’re getting into a “mine is better than yours” game, but rather to see how mine stacks up against Doug’s, bearing in mind his is a 5 disk stripe natively attached to his machine (I’m [...]
11g PX tracefiles now have the tracefile identifier on them
Now that I’ve got 11g up and running on OpenSuse 10.2 on a VMWare 6 VM, I’ve had time to do some playing with the latest and greatest release and the first thing I’ve noticed, when running some of Doug’s PX test scripts, is that the trace files generated for PX slaves now have the [...]
ORA-07455 and EXPLAIN PLAN…and statements which, perhaps, shouldn’t run
I encountered a scenario today which I thought was strange in a number of ways…hence, irresistible to a quick blog post. The scenario started with an end user of my warehouse emailing me a query that was returning an error message dialog box, warning the user before they ran the query, that they had insufficient [...]