Andrew Dunstan wrote:
>
>
> Simon Riggs wrote:
> >
> > - Heap-Only Tuples (HOT) accelerate space reuse for UPDATEs
> > change to
> > "Heap-Only Tuples (HOT) improve performance of frequent UPDATEs"
> >
> >
> >
>
> I think we need to qualify this, or it could be quite misleading.
> perhaps add "that don't affect indexed columns" or something like that.
This is covered in the detailed text below the item:
<para> Heap-Only Tuples (<acronym>HOT</>) accelerate space reuse for <command>UPDATE</>s (Pavan
Deolasee,with ideas from many others) </para>
<para> <command>UPDATE</>s and <command>DELETE</>s leave dead tuples behind, as do failed
<command>INSERT</>s. Previously only <command>VACUUM</> could reclaim space taken by dead tuples. With
<acronym>HOT</>dead tuple space can be reclaimed at the time of <command>UPDATE</> or <command>INSERT</> if no
changesare made to indexed columns. This allows for more consistent performance. Also, <acronym>HOT</>
avoidsadding duplicate index entries.
I just updated the wording so the index issue is clearer.
-- Bruce Momjian <bruce@momjian.us> http://momjian.us EnterpriseDB
http://postgres.enterprisedb.com
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