Evaluating query performance with caching in PostgreSQL 9.1.6

<span style="font-family:Verdana; color:#000000; font-size:10pt;"><div>Two questions Please</div><div><br
/></div><div>1.)Is there any way to clear the <b>cache</b> so that we can ensure that when we run "<b>explain
analyze</b>"on a query and make some minor adjustments to that query and re-execute, the plan is not cached. Since the
cachedplan returns runtimes that are much lower than the initial execution, so we don't know for certain the tweaks we
madeimproved the performance of the query, without having to bounce the database?<br /></div><div><br /></div><div>2.)
Iam noticing that when I look at pg_stat_activities: autovacuum is re-processing some old Partition tables way back in
2007,which are static and are essentially read-only partitions. the line item in pg_stat reads as follows:
autovacuum:VACUUMpublic.digi_sas_y2007m07 (to prevent wraparound). Is there a way to have autovacuum skip these static
typepartition tables, and only process partitions that have had; Inserts, updates, or deletes attributed to them?
</div><div><br/></div><div>thanks.<br /></div><div> </div></span>