<itemizedlist>

<listitem>

<para>

The update does not modify any columns referenced by the table's

indexes, including expression and partial indexes.

The update does not modify any columns referenced by the table's indexes,

not including summarizing indexes. The only summarizing index method in

the core <productname>PostgreSQL</productname> distribution is <link

linkend="brin">BRIN</link>.

</para>

</listitem>

<listitem>

<itemizedlist>

<listitem>

<para>

New index entries are not needed to represent updated rows.

New index entries are not needed to represent updated rows, however,

summary indexes may still need to be updated.

</para>

</listitem>

<listitem>

</para>

<para>

In summary, heap-only tuple updates can only be created

if columns used by indexes are not updated. You can

increase the likelihood of sufficient page space for

You can increase the likelihood of sufficient page space for

<acronym>HOT</acronym> updates by decreasing a table's <link

linkend="reloption-fillfactor"><literal>fillfactor</literal></link>.

If youdon't, <acronym>HOT</acronym> updates will still happen because

new rowswill naturally migrate to new pages and existing pages with

sufficient freespace for new row versions. The system view <link

linkend="reloption-fillfactor"><literal>fillfactor</literal></link>. If you

don't, <acronym>HOT</acronym> updates will still happen because new rows

will naturally migrate to new pages and existing pages with sufficient free

space for new row versions. The system view <link

linkend="monitoring-pg-stat-all-tables-view">pg_stat_all_tables</link>

allows monitoring of the occurrence of HOT and non-HOT updates.

</para>