Ravi Krishna <srkrish...@aol.com> writes:
> I loaded 133 million rows to a wide table (more than 100 cols) via COPY. The
> table has
> no index at this time. Since I am the only user I don't see any other
> activity.
> Now when I run select count(*) on the table where I just loaded data, it runs
> for ever,
> more than 10min and still running. Intrigued, I checked locks and saw
> nothing. Then I noticed something
> strange. When select count(*) runs, PG is writing to wal_logs, and that too
> a large amount. Why?
That represents setting the yes-this-row-is-committed hint bits on the
newly loaded rows. The first access to any such row will set that bit,
whether it's a select or a VACUUM or whatever.
regards, tom lane
