It’s sad that it takes a Bank Holiday weekend for me to get round to doing some more research on parallel execution. Anyway, I was on the verge of modifying the following line from the PX paper …
The trace files for the slave processes may be created in background_dump_dest, rather than the standard user_dump_dest. This is version dependant and the trace file for the query coordinator will be in user_dump_dest in any case
… because I’d yet to see the trace files appear in user_dump_dest and a comment on asktom had got me thinking – ‘Yes, px slaves are background processes so why would the trace files ever appear in user_dump_dest?’Then while I was playing around looking at how many slaves Oracle might assign to various statements using some scripts and suggestions from J Lewis, I noticed that the slave trace files are appearing in user_dump_dest. This is with 9.2.0.1.0 on Windows XP Home. I’m using 9.2 because I want to see the discrete SQL statements that the slaves are processing.So, just an interesting anomaly from what I’ve seen previously. I’ll check it out on other versions / OS in future.