query. We could reduce that by specifying a larger signature length.

In this example, creating the index with <literal>length=200</>

reduced the number of false positives to 55; but it doubled the index size

</para>

<para>

</programlisting>

Although this query runs much faster than with either of the single

indexes, we pay a large penalty in index size. Each of the single-column

more than 8 times the space used by the bloom index.

</para>

</sect2>

segments or <quote>pages</> small enough to be conveniently stored as rows

in <structname>pg_largeobject</structname>.

The amount of data per page is defined to be <symbol>LOBLKSIZE</> (which is currently

</para>

<para>

cache, where performance might degrade. This setting may have no

effect on some platforms. The valid range is between

<literal>0</literal>, which disables controlled writeback, and

<literal>0</> elsewhere. (Non-default values of

<symbol>BLCKSZ</symbol> change the default and maximum.)

This parameter can only be set in the <filename>postgresql.conf</>

than the OS's page cache, where performance might degrade. This

setting may have no effect on some platforms. The valid range is

between <literal>0</literal>, which disables controlled writeback,

Linux, <literal>0</> elsewhere. (Non-default values of

<symbol>BLCKSZ</symbol> change the default and maximum.)

This parameter can only be set in the <filename>postgresql.conf</>

checkpoints. This is a soft limit; WAL size can exceed

<varname>max_wal_size</> under special circumstances, like

under heavy load, a failing <varname>archive_command</>, or a high

Increasing this parameter can increase the amount of time needed for

crash recovery.

This parameter can only be set in the <filename>postgresql.conf</>

always recycled for future use at a checkpoint, rather than removed.

This can be used to ensure that enough WAL space is reserved to

handle spikes in WAL usage, for example when running large batch

This parameter can only be set in the <filename>postgresql.conf</>

file or on the server command line.

</para>

the physical requirement on disk might be less. Very long values are also

stored in background tables so that they do not interfere with rapid

access to shorter column values. In any case, the longest

maximum value that will be allowed for <replaceable>n</> in the data

type declaration is less than that. It wouldn't be useful to

change this because with multibyte character encodings the number of

<term><literal>sqlilongdata</></term>

<listitem>

<para>

</para>

</listitem>

</varlistentry>

<para>

Also check that you have sufficient disk space. You will need about

the installation directory. An empty database cluster takes about

flat text file with the same data would take. If you are going to

run the regression tests you will temporarily need up to an extra

space.

</para>

</sect1>

createlang: language installation failed: ERROR: could not load library "/opt/dbs/pgsql748/lib/plperl.so": Bad address

</screen>

Another example is out of memory errors in the PostgreSQL server

failing.

</para>

and memory model used by the server process. By default, all

binaries built on AIX are 32-bit. This does not depend upon

hardware type or kernel in use. These 32-bit processes are

heap as it shares a single segment with the stack.

</para>

settings to find a configuration that works satisfactorily. This

use of <symbol>LDR_CNTRL</symbol> tells AIX that you want the

server to have <symbol>MAXDATA</symbol> bytes set aside for the

configuration,

<command>ldedit</command> can be used to modify the binaries so

that they default to using the desired heap size. PostgreSQL can

larger than a single database page into a secondary storage area per table.

This makes the large object facility partially obsolete. One

remaining advantage of the large object facility is that it allows values

done efficiently, while most operations on a <acronym>TOAST</acronym>ed

field will read or write the whole value as a unit.

</para>

A <firstterm>label path</firstterm> is a sequence of zero or more

labels separated by dots, for example <literal>L1.L2.L3</>, representing

a path from the root of a hierarchical tree to a particular node. The

preferable. In practice this is not a major limitation; for example,

the longest label path in the DMOZ catalog (<ulink

url="http://www.dmoz.org"></ulink>) is about 240 bytes.

Limit (throttle) the maximum amount of data transferred from server

to client per unit of time. The expected unit is kilobytes per second.

If this option is specified, the value must either be equal to zero

If zero is passed or the option is not specified, no restriction is

imposed on the transfer.

</para>

</term>

<listitem>

<para>

default maximum total size is 2097152

pages. A page is almost always 4096 bytes except in unusual

kernel configurations with <quote>huge pages</quote>

<para>

The shared memory size settings can be changed via the

<screen>

<prompt>$</prompt> <userinput>sysctl -w kernel.shmmax=17179869184</userinput>

<prompt>$</prompt> <userinput>sysctl -w kernel.shmall=4194304</userinput>

</para>

<para>

</para>

<para>

</term>

<listitem>

<para>

segment is allowed. To increase the setting, first change to the

directory <filename>/etc/conf/cf.d</>. To display the current value of

<varname>SHMMAX</>, run:

<listitem>

<para>

On <productname>UnixWare</> 7, the maximum size for shared

To display the current value of <varname>SHMMAX</>, run:

<programlisting>

/etc/conf/bin/idtune -g SHMMAX