CONNECT BY oddity

This week I’ve seen an issue with a CONNECT BY query: for some reason Oracle 10.2.0.4 decided to build a weird plan (the query is weird too, but that’s not my point here ). An explanation of why that happened looks interesting, so here it is.

Control file sequential read

There was a thread recently on the OTN forum (it’s currently down, that’s why I’m writing in the blog; here is a stale version of the page from Google cache; at the time of writing this version had 1 comment) about reasons for control file sequential read accounted to particular query.