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The I/O needed for a checkpoint is now spread over a fairly long

period of time, rather than being spat out in a burst. This happens

only for background checkpoints carried out by the bgwriter; other

cases, such as a shutdown checkpoint, are still

done at full speed.

cases, such as a shutdown checkpoint, are still done at full speed.

</para>

</listitem>

</para>

<para>

Thischange allows a significant percentage reduction inthe on-disk

size of shortcharacter-string fields.

Thissignificantly reducesthe on-disk size of short

character-string fields.

</para>

</listitem>

We keep a heap of the current best N tuples and sift-up new tuples

into it as we scan the input. For M input tuples this means only

about M*log(N) comparisons instead of M*log(M), not to mention a lot

less workspace when N is small--- avoiding spill-to-disk for large

less workspace when N is small&mdash; avoiding spill-to-disk for large

M is actually the most attractive thing about it.

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<para>

This provides full gettimeofday() resolution for the timestamps,

which might be useful when attempting to do point-in-time recovery

--- previously it was not possible to specify the stop point with

&mdash; previously it was not possible to specify the stop point with

sub-second resolution.

</para>

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This is a list to allow spreading the load across multiple

tablespaces; a random list element is chosen each time a temp object

is to be created. Temp files are not stored in per-database

pgsql_tmp/ directories anymore, but per-tablespace directories.

pgsql_tmp/ directories anymore, butinper-tablespace directories.

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<para>

While it's (still) possible to perform these operations using ALTER

While it has long been possible to perform these operations using ALTER

TABLE, users were often surprised that they couldn't say ALTER VIEW

or ALTER SEQUENCE as appropriate.

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<para>

Make NOTIFY/LISTEN/UNLISTEN only accept simple relation names

Make NOTIFY/LISTEN/UNLISTEN only accept identifiers without a schema

qualifier

(Bruce)

</para>

</para>

<para>

These commands simplify resetting a database session to initial

These commands simplify resetting a database session toitsinitial

state, and are particularly handy for connection-pooling software.

</para>

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<listitem>

<para>

Add a "uuid" data type similar to that defined in RFC 4122 (Gevik

Babakhani)

Babakhani, Neil)

</para>

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</para>

<para>

Thisenables use ofhash indexes and hash-based plans with

Thisallowshash indexes and hash-based plans to be used with

the numeric datatype.

</para>

</listitem>

<listitem>

<para>

Allow leading and trailing

whitespace in the input to the booleantype (Neil)

Allow leading and trailing whitespace in the input to the boolean

type (Neil)

</para>

</listitem>

<listitem>

<para>

Implement RETURN QUERY for PL/PgSQL (Pavel Stehule,Tom)

Implement RETURN QUERY for PL/PgSQL (Pavel Stehule,Neil)

</para>

<para>

</para>

<para>

Use configure option --with-ossp-uuid to activate.

Use configure option --with-ossp-uuid to activate. This takes

advantage of the new UUID builtin type.

</para>

</listitem>