Joshua Reich <josh@root.net> writes:
> Is it safe to use the output of EXPLAIN in regression tests?
No, not unless you want the test to break every other week.
> I want to
> make sure that certain GiST indexes are being used by sample queries,
About the best bet is to make sure that's the *only* available index,
and set enable_seqscan = off to be sure.
In some cases, you can use the ordering of the returned rows as a proxy
--- if they're returned in something other than heap order then it must
have used an index. I'm not sure if this will be a stable answer for
GIST indexes though.
regards, tom lane