Re: Vacuum full: alternatives? - Mailing list pgsql-general

From David G. Johnston
Subject Re: Vacuum full: alternatives?
Date
Msg-id CAKFQuwavBni1b3TYkpNR71QkmCifpaOEAguihked62MwbwrT4g@mail.gmail.com
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In response to Re: R: Vacuum full: alternatives?  (John R Pierce <pierce@hogranch.com>)
Responses Re: Vacuum full: alternatives?
List pgsql-general
On Monday, June 20, 2016, John R Pierce <pierce@hogranch.com> wrote:
On 6/20/2016 8:03 AM, Scott Mead wrote:

I believe that free space is only available to UPDATE, not INSERT.

incorrect.   in fact, an update is performed identically to an INSERT + DELETE(old)


Except for heap-only-tuple optimization, right?  We cannot build a HOT chain if the user requests a delete separately since their is no longer an association to trace from the old record.

I suspect this affects free space usage to some degree as well but I agree and believe that the reclaimed space is not forbidden to be used (I wouldn't rely on my word though and haven't tried to find relevant documentation).

David J.

 

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