<para>
This is often called "index-only scans" or "covering indexes".
This is possible for heap pages with exclusively all-visible
- tuples, as reported by the visibility map.
+ tuples, as reported by the visibility map. The visibility map was
+ made crash-safe as a necessary part of implementing this feature.
</para>
</listitem>
-
+
<listitem>
<para>
Allow frequently uncontended locks to be recorded using a new
</para>
</listitem>
- <listitem>
- <para>
- Make the visibility map crash-safe (Robert Haas, Noah Misch)
- </para>
-
- <para>
- This helps vacuum be more efficient, and is necessary for
- index-only scans.
- </para>
- </listitem>
-
<listitem>
<para>
Improve PowerPC and Itanium spinlock performance (Manabu Ori,