vacuum and postgresql.conf settings

Started by Walter Vaughanalmost 19 years ago5 messagesgeneral
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#1Walter Vaughan
wvaughan@steelerubber.com

I am not even sure this is a problem.

INFO: "data_import_customer2": scanned 3000 of 5033 pages, containing 84905
live rows and 0 dead rows; 3000 rows in sample, 142442 estimated total rows

Do I have some setting wrong?

#2Francisco Reyes
lists@stringsutils.com
In reply to: Walter Vaughan (#1)
Re: vacuum and postgresql.conf settings

Walter Vaughan writes:

I am not even sure this is a problem.
INFO: "data_import_customer2": scanned 3000 of 5033 pages, containing 84905
live rows and 0 dead rows; 3000 rows in sample, 142442 estimated total rows

I don't believe it is a problem.
I think it is just normal output of the vacuum.
What made you think there could be a problem?

#3Walter Vaughan
wvaughan@steelerubber.com
In reply to: Francisco Reyes (#2)
Re: vacuum and postgresql.conf settings

Francisco Reyes wrote:

Walter Vaughan writes:

I am not even sure this is a problem.
INFO: "data_import_customer2": scanned 3000 of 5033 pages, containing
84905 live rows and 0 dead rows; 3000 rows in sample, 142442 estimated
total rows

I don't believe it is a problem.
I think it is just normal output of the vacuum.
What made you think there could be a problem?

Well, why did it only scan 3000 pages out of 5033? It decided it didn't need to?
It took a sample and decided it was gonna be okay?

#4Francisco Reyes
lists@stringsutils.com
In reply to: Walter Vaughan (#1)
Re: vacuum and postgresql.conf settings

Walter Vaughan writes:

Well, why did it only scan 3000 pages out of 5033? It decided it didn't need to?
It took a sample and decided it was gonna be okay?

I don't know. Hopefully others with more knowledge can answer.

I think it could be because the pages did not need to be looked at.
Perhaps the database tracks whether a page has deleted information and those
are the ones that vacuum looks into.

#5Alvaro Herrera
alvherre@2ndquadrant.com
In reply to: Walter Vaughan (#3)
Re: vacuum and postgresql.conf settings

Walter Vaughan wrote:

Francisco Reyes wrote:

Walter Vaughan writes:

I am not even sure this is a problem.
INFO: "data_import_customer2": scanned 3000 of 5033 pages, containing
84905 live rows and 0 dead rows; 3000 rows in sample, 142442 estimated
total rows

I don't believe it is a problem.
I think it is just normal output of the vacuum.
What made you think there could be a problem?

Well, why did it only scan 3000 pages out of 5033? It decided it didn't
need to? It took a sample and decided it was gonna be okay?

These lines are for the ANALYZE step. It doesn't need to scan all the
pages. It picks 3000 at random for computing stats. The VACUUM step
(which happens before ANALYZE) does walk all pages.

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