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>Chapter 23. Routine Database Maintenance Tasks</H1
><DIV
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><DL
><DT
><B
>Table of Contents</B
></DT
><DT
>23.1. <A
HREF="routine-vacuuming.html"
>Routine Vacuuming</A
></DT
><DD
><DL
><DT
>23.1.1. <A
HREF="routine-vacuuming.html#VACUUM-BASICS"
>Vacuuming Basics</A
></DT
><DT
>23.1.2. <A
HREF="routine-vacuuming.html#VACUUM-FOR-SPACE-RECOVERY"
>Recovering Disk Space</A
></DT
><DT
>23.1.3. <A
HREF="routine-vacuuming.html#VACUUM-FOR-STATISTICS"
>Updating Planner Statistics</A
></DT
><DT
>23.1.4. <A
HREF="routine-vacuuming.html#VACUUM-FOR-VISIBILITY-MAP"
>Updating The Visibility Map</A
></DT
><DT
>23.1.5. <A
HREF="routine-vacuuming.html#VACUUM-FOR-WRAPAROUND"
>Preventing Transaction ID Wraparound Failures</A
></DT
><DT
>23.1.6. <A
HREF="routine-vacuuming.html#AUTOVACUUM"
>The Autovacuum Daemon</A
></DT
></DL
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><DT
>23.2. <A
HREF="routine-reindex.html"
>Routine Reindexing</A
></DT
><DT
>23.3. <A
HREF="logfile-maintenance.html"
>Log File Maintenance</A
></DT
></DL
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><P
> <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
>, like any database software, requires that certain tasks
be performed regularly to achieve optimum performance. The tasks
discussed here are <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>required</I
></SPAN
>, but they
are repetitive in nature and can easily be automated using standard
tools such as <SPAN
CLASS="APPLICATION"
>cron</SPAN
> scripts or
Windows' <SPAN
CLASS="APPLICATION"
>Task Scheduler</SPAN
>. It is the database
administrator's responsibility to set up appropriate scripts, and to
check that they execute successfully.
</P
><P
> One obvious maintenance task is the creation of backup copies of the data on a
regular schedule. Without a recent backup, you have no chance of recovery
after a catastrophe (disk failure, fire, mistakenly dropping a critical
table, etc.). The backup and recovery mechanisms available in
<SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> are discussed at length in
<A
HREF="backup.html"
>Chapter 24</A
>.
</P
><P
> The other main category of maintenance task is periodic <SPAN
CLASS="QUOTE"
>"vacuuming"</SPAN
>
of the database. This activity is discussed in
<A
HREF="routine-vacuuming.html"
>Section 23.1</A
>. Closely related to this is updating
the statistics that will be used by the query planner, as discussed in
<A
HREF="routine-vacuuming.html#VACUUM-FOR-STATISTICS"
>Section 23.1.3</A
>.
</P
><P
> Another task that might need periodic attention is log file management.
This is discussed in <A
HREF="logfile-maintenance.html"
>Section 23.3</A
>.
</P
><P
> <A
HREF="https://bucardo.org/check_postgres/"
TARGET="_top"
><SPAN
CLASS="APPLICATION"
>check_postgres</SPAN
></A
>
is available for monitoring database health and reporting unusual
conditions. <SPAN
CLASS="APPLICATION"
>check_postgres</SPAN
> integrates with
Nagios and MRTG, but can be run standalone too.
</P
><P
> <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> is low-maintenance compared
to some other database management systems. Nonetheless,
appropriate attention to these tasks will go far towards ensuring a
pleasant and productive experience with the system.
</P
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