Re: Autovacuum daemon internal handling

> in 8.2 "naptime" means "time to sleep after we finish a job". So even
> if the previous task takes an hour, it will still sleep a minute before
> doing another round. (Note that this setting has a different meaning in
> later releases).

I couldn’t understand the difference in meaning of "autovacuum_naptime" between 8.2 and later releases from the documentation. May be I'm not understanding/seeing the subtle difference in the documentation lines mentioned. I referred these 3 doc links:
http://www.postgresql.org/docs/8.2/interactive/runtime-config-autovacuum.html
http://www.postgresql.org/docs/8.3/interactive/runtime-config-autovacuum.html
http://www.postgresql.org/docs/8.4/interactive/runtime-config-autovacuum.html

8.2 doc says "Specifies the delay between activity rounds for the autovacuum daemon...."
8.3 & 8.4 doc says "Specifies the minimum delay between autovacuum runs on any given database....."

Can you please make me clear on this?

> If autovacuum cannot keep up with all the vacuumable tables, you're in
> trouble and should probably schedule vacuum externally. (This also
> changed in later releases).

Can you please point me to relevant documentation links on this change?

>> 2. The columns "last_autovaccum" and 'last_autoanalyze" in
>> pg_stat_user_tables shows the start time or end time of the operation?

> End time.
Is there any way to find out the start time of "last_autovaccum" and/or 'last_autoanalyze" for a given table in 8.2.3? So that I can isolate the tables that are taking too long time to complete vacuum and/or analyze and I can perform them externally if need.