-->

<para>

Allow inserts, not only updates and deletes, to

trigger<link linkend="autovacuum">autovacuum</link> activity

Allow inserts, not only updates and deletes, to trigger vacuuming

activity in<link linkend="autovacuum">autovacuum</link>

(Laurenz Albe, Darafei Praliaskouski)

</para>

<para>

This new behavior reduces the work that will be necessary later

when the table needs to be frozen, and it allows pages to be

marked as all-visible sooner. All-visible pages allow index-only

scans to access fewer heap rows.

Previously, insert-only activity would trigger auto-analyze but

not auto-vacuum, on the grounds that there could not be any dead

tuples to remove. However, a vacuum scan has other useful

side-effects such as setting page-all-visible bits, which improves

the efficiency of index-only scans. Also, allowing an insert-only

table to receive periodic vacuuming helps to spread out the work

of <quote>freezing</quote> old tuples, so that there is not

suddenly a large amount of freezing work to do when the entire

table reaches the anti-wraparound threshold all at once.

</para>

<para>

If necessary, this behavior can be adjusted with the new

parameters <xref linkend="guc-autovacuum-vacuum-insert-threshold"/>

and <xref linkend="guc-autovacuum-vacuum-insert-scale-factor"/>, or

the equivalent table storage options.

</para>

</listitem>

-->

<para>

Add <xref linkend="guc-maintenance-io-concurrency"/>to control I/O

concurrency for maintenance operations (Thomas Munro)

Add <xref linkend="guc-maintenance-io-concurrency"/>parameter to

control I/Oconcurrency for maintenance operations (Thomas Munro)

</para>

</listitem>