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<sect1 id="release-9-3-21">

<title>Release 9.3.21</title>

<formalpara>

<title>Release date:</title>

<para>2018-02-08</para>

</formalpara>

<para>

This release contains a variety of fixes from 9.3.20.

For information about new features in the 9.3 major release, see

<xref linkend="release-9-3">.

</para>

<sect2>

<title>Migration to Version 9.3.21</title>

<para>

A dump/restore is not required for those running 9.3.X.

</para>

<para>

However, if you are upgrading from a version earlier than 9.3.18,

see <xref linkend="release-9-3-18">.

</para>

</sect2>

<sect2>

<title>Changes</title>

<itemizedlist>

<listitem>

<para>

Fix vacuuming of tuples that were updated while key-share locked

(Andres Freund, &Aacute;lvaro Herrera)

</para>

<para>

In some cases <command>VACUUM</command> would fail to remove such

tuples even though they are now dead, leading to assorted data

corruption scenarios.

</para>

</listitem>

<listitem>

<para>

Fix inadequate buffer locking in some LSN fetches (Jacob Champion,

Asim Praveen, Ashwin Agrawal)

</para>

<para>

These errors could result in misbehavior under concurrent load.

The potential consequences have not been characterized fully.

</para>

</listitem>

<listitem>

<para>

Avoid unnecessary failure in a query on an inheritance tree that

occurs concurrently with some child table being removed from the tree

by <command>ALTER TABLE NO INHERIT</command> (Tom Lane)

</para>

</listitem>

<listitem>

<para>

Repair failure with correlated sub-<literal>SELECT</literal>

inside <literal>VALUES</literal> inside a <literal>LATERAL</literal>

subquery (Tom Lane)

</para>

</listitem>

<listitem>

<para>

Fix <quote>could not devise a query plan for the given query</quote>

planner failure for some cases involving nested <literal>UNION

ALL</literal> inside a lateral subquery (Tom Lane)

</para>

</listitem>

<listitem>

<para>

Fix <function>has_sequence_privilege()</function> to

support <literal>WITH GRANT OPTION</literal> tests,

as other privilege-testing functions do (Joe Conway)

</para>

</listitem>

<listitem>

<para>

In databases using UTF8 encoding, ignore any XML declaration that

asserts a different encoding (Pavel Stehule, Noah Misch)

</para>

<para>

We always store XML strings in the database encoding, so allowing

libxml to act on a declaration of another encoding gave wrong results.

In encodings other than UTF8, we don't promise to support non-ASCII

XML data anyway, so retain the previous behavior for bug compatibility.

This change affects only <function>xpath()</function> and related

functions; other XML code paths already acted this way.

</para>

</listitem>

<listitem>

<para>

Provide for forward compatibility with future minor protocol versions

(Robert Haas, Badrul Chowdhury)

</para>

<para>

Up to now, <productname>PostgreSQL</productname> servers simply

rejected requests to use protocol versions newer than 3.0, so that

there was no functional difference between the major and minor parts

of the protocol version number. Allow clients to request versions 3.x

without failing, sending back a message showing that the server only

understands 3.0. This makes no difference at the moment, but

back-patching this change should allow speedier introduction of future

minor protocol upgrades.

</para>

</listitem>

<listitem>

<para>

Prevent stack-overflow crashes when planning extremely deeply

nested set operations

(<literal>UNION</literal>/<literal>INTERSECT</literal>/<literal>EXCEPT</literal>)

(Tom Lane)

</para>

</listitem>

<listitem>

<para>

Fix null-pointer crashes for some types of LDAP URLs appearing

in <filename>pg_hba.conf</filename> (Thomas Munro)

</para>

</listitem>

<listitem>

<para>

Fix sample <function>INSTR()</function> functions in the PL/pgSQL

documentation (Yugo Nagata, Tom Lane)

</para>

<para>

These functions are stated to

be <trademark class="registered">Oracle</trademark> compatible, but

they weren't exactly. In particular, there was a discrepancy in the

interpretation of a negative third parameter: Oracle thinks that a

negative value indicates the last place where the target substring can

begin, whereas our functions took it as the last place where the

target can end. Also, Oracle throws an error for a zero or negative

fourth parameter, whereas our functions returned zero.

</para>

<para>

The sample code has been adjusted to match Oracle's behavior more

precisely. Users who have copied this code into their applications

may wish to update their copies.

</para>

</listitem>

<listitem>

<para>

Fix <application>pg_dump</application> to make ACL (permissions),

comment, and security label entries reliably identifiable in archive

output formats (Tom Lane)

</para>

<para>

The <quote>tag</quote> portion of an ACL archive entry was usually

just the name of the associated object. Make it start with the object

type instead, bringing ACLs into line with the convention already used

for comment and security label archive entries. Also, fix the

comment and security label entries for the whole database, if present,

to make their tags start with <literal>DATABASE</literal> so that they

also follow this convention. This prevents false matches in code that

tries to identify large-object-related entries by seeing if the tag

starts with <literal>LARGE OBJECT</literal>. That could have resulted

in misclassifying entries as data rather than schema, with undesirable

results in a schema-only or data-only dump.

</para>

<para>

Note that this change has user-visible results in the output

of <command>pg_restore --list</command>.

</para>

</listitem>

<listitem>

<para>

In <application>ecpg</application>, detect indicator arrays that do

not have the correct length and report an error (David Rader)

</para>

</listitem>

<listitem>

<para>

Avoid triggering a libc assertion

in <filename>contrib/hstore</filename>, due to use

of <function>memcpy()</function> with equal source and destination

pointers (Tomas Vondra)

</para>

</listitem>

<listitem>

<para>

Provide modern examples of how to auto-start Postgres on macOS

(Tom Lane)

</para>

<para>

The scripts in <filename>contrib/start-scripts/osx</filename> use

infrastructure that's been deprecated for over a decade, and which no

longer works at all in macOS releases of the last couple of years.

Add a new subdirectory <filename>contrib/start-scripts/macos</filename>

containing scripts that use the newer <application>launchd</application>

infrastructure.

</para>

</listitem>

<listitem>

<para>

Fix incorrect selection of configuration-specific libraries for

OpenSSL on Windows (Andrew Dunstan)

</para>

</listitem>

<listitem>

<para>

Support linking to MinGW-built versions of libperl (Noah Misch)

</para>

<para>

This allows building PL/Perl with some common Perl distributions for

Windows.

</para>

</listitem>

<listitem>

<para>

Fix MSVC build to test whether 32-bit libperl

needs <literal>-D_USE_32BIT_TIME_T</literal> (Noah Misch)

</para>

<para>

Available Perl distributions are inconsistent about what they expect,

and lack any reliable means of reporting it, so resort to a build-time

test on what the library being used actually does.

</para>

</listitem>

<listitem>

<para>

On Windows, install the crash dump handler earlier in postmaster

startup (Takayuki Tsunakawa)

</para>

<para>

This may allow collection of a core dump for some early-startup

failures that did not produce a dump before.

</para>

</listitem>

<listitem>

<para>

On Windows, avoid encoding-conversion-related crashes when emitting

messages very early in postmaster startup (Takayuki Tsunakawa)

</para>

</listitem>

<listitem>

<para>

Use our existing Motorola 68K spinlock code on OpenBSD as

well as NetBSD (David Carlier)

</para>

</listitem>

<listitem>

<para>

Add support for spinlocks on Motorola 88K (David Carlier)

</para>

</listitem>

<listitem>

<para>

Update time zone data files to <application>tzdata</application>

release 2018c for DST law changes in Brazil, Sao Tome and Principe,

plus historical corrections for Bolivia, Japan, and South Sudan.

The <literal>US/Pacific-New</literal> zone has been removed (it was

only an alias for <literal>America/Los_Angeles</literal> anyway).

</para>

</listitem>

</itemizedlist>

</sect2>

</sect1>

<sect1 id="release-9-3-20">

<title>Release 9.3.20</title>