Remove pgsql_tmp directory FAQ item.
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Bruce Momjian
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doc/FAQ
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doc/FAQ
@ -1,7 +1,7 @@
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Frequently Asked Questions (FAQ) for PostgreSQL
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Last updated: Tue Feb 1 16:10:47 EST 2005
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Last updated: Wed Feb 2 08:40:42 EST 2005
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Current maintainer: Bruce Momjian (pgman@candle.pha.pa.us)
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@ -41,10 +41,9 @@
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3.3) How do I tune the database engine for better performance?
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3.4) What debugging features are available?
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3.5) Why do I get "Sorry, too many clients" when trying to connect?
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3.6) What is in the pgsql_tmp directory?
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3.7) Why do I need to do a dump and restore to upgrade PostgreSQL
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3.6) Why do I need to do a dump and restore to upgrade PostgreSQL
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releases?
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3.8) What computer hardware should I use?
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3.7) What computer hardware should I use?
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Operational Questions
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@ -430,18 +429,7 @@
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processes it can start by changing the max_connections value in
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postgresql.conf and restarting the postmaster.
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3.6) What is in the pgsql_tmp directory?
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This directory contains temporary files generated by the query
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executor. For example, if a sort needs to be done to satisfy an ORDER
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BY and the sort requires more space than the backend's -S parameter
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allows, then temporary files are created here to hold the extra data.
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The temporary files are usually deleted automatically, but might
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remain if a backend crashes during a sort. A stop and restart of the
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postmaster will remove files from those directories.
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3.7) Why do I need to do a dump and restore to upgrade between major
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3.6) Why do I need to do a dump and restore to upgrade between major
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PostgreSQL releases?
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The PostgreSQL team makes only small changes between minor releases,
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@ -452,7 +440,7 @@
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files. A dump outputs data in a generic format that can then be loaded
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in using the new internal format.
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3.8) What computer hardware should I use?
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3.7) What computer hardware should I use?
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Because PC hardware is mostly compatible, people tend to believe that
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all PC hardware is of equal quality. It is not. ECC RAM, SCSI, and
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@ -651,12 +639,12 @@
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4.10) What is the difference between the various character types?
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Type Internal Name Notes
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VARCHAR(n) varchar size specifies maximum length, no padding
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CHAR(n) bpchar blank padded to the specified fixed length
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TEXT text no specific upper limit on length
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BYTEA bytea variable-length byte array (null-byte safe)
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"char" char one character
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Type Internal Name Notes
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VARCHAR(n) varchar size specifies maximum length, no padding
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CHAR(n) bpchar blank padded to the specified fixed length
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TEXT text no specific upper limit on length
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BYTEA bytea variable-length byte array (null-byte safe)
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"char" char one character
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You will see the internal name when examining system catalogs and in
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some error messages.
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@ -10,7 +10,7 @@
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alink="#0000ff">
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<H1>Frequently Asked Questions (FAQ) for PostgreSQL</H1>
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<P>Last updated: Tue Feb 1 16:10:47 EST 2005</P>
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<P>Last updated: Wed Feb 2 08:40:42 EST 2005</P>
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<P>Current maintainer: Bruce Momjian (<A href=
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"mailto:pgman@candle.pha.pa.us">pgman@candle.pha.pa.us</A>)
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@ -61,11 +61,9 @@
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<A href="#3.4">3.4</A>) What debugging features are available?<BR>
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<A href="#3.5">3.5</A>) Why do I get <I>"Sorry, too many
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clients"</I> when trying to connect?<BR>
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<A href="#3.6">3.6</A>) What is in the <I>pgsql_tmp</I>
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directory?<BR>
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<A href="#3.7">3.7</A>) Why do I need to do a dump and restore
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<A href="#3.6">3.6</A>) Why do I need to do a dump and restore
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to upgrade PostgreSQL releases?<BR>
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<A href="#3.8">3.8</A>) What computer hardware should I use?<BR>
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<A href="#3.7">3.7</A>) What computer hardware should I use?<BR>
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<H2 align="center">Operational Questions</H2>
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@ -573,19 +571,7 @@
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<I>max_connections</I> value in <I>postgresql.conf</I> and
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restarting the <I>postmaster</I>.</P>
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<H4><A name="3.6">3.6</A>) What is in the <I>pgsql_tmp</I> directory?</H4>
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<P>This directory contains temporary files generated by the query
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executor. For example, if a sort needs to be done to satisfy an
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<SMALL>ORDER BY</SMALL> and the sort requires more space than the
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backend's <I>-S</I> parameter allows, then temporary files are created
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here to hold the extra data.</P>
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<P>The temporary files are usually deleted automatically, but might
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remain if a backend crashes during a sort. A stop and restart of the
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<I>postmaster</I> will remove files from those directories.</P>
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<H4><A name="3.7">3.7</A>) Why do I need to do a dump and restore
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<H4><A name="3.6">3.6</A>) Why do I need to do a dump and restore
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to upgrade between major PostgreSQL releases?</H4>
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<P>The PostgreSQL team makes only small changes between minor releases,
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@ -596,7 +582,7 @@
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data in a generic format that can then be loaded in using the new internal
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format.</P>
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<H4><A name="3.8">3.8</A>) What computer hardware should I use?</H4>
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<H4><A name="3.7">3.7</A>) What computer hardware should I use?</H4>
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<P>Because PC hardware is mostly compatible, people tend to believe that
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all PC hardware is of equal quality. It is not. ECC RAM, SCSI, and
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@ -672,7 +658,7 @@
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table, and a database?</H4>
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<P>These are the limits:</P>
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<CENTER>
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<BLOCKQUOTE>
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<TABLE BORDER=1>
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<TR><TD>Maximum size for a database?</TD><TD>unlimited (32 TB databases
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exist)</TD></TR>
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@ -685,8 +671,7 @@ on column types</TD></TR>
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<TR><TD>Maximum number of indexes on a
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table?</TD><TD>unlimited</TD></TR>
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</TABLE>
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</CENTER>
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<BR>
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</BLOCKQUOTE>
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<P>Of course, these are not actually unlimited, but limited to
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available disk space and memory/swap space. Performance may suffer
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@ -837,7 +822,7 @@ table?</TD><TD>unlimited</TD></TR>
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<H4><A name="4.10">4.10</A>) What is the difference between the
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various character types?</H4>
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<CENTER>
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<BLOCKQUOTE>
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<TABLE BORDER=1>
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<TR><TH>Type</TH><TH>Internal Name</TH><TH>Notes</TH></TR>
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<TR><TD>VARCHAR(n)</TD><TD>varchar</TD><TD>size specifies maximum
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@ -850,7 +835,8 @@ length</TD></TR>
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(null-byte safe)</TD></TR>
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<TR><TD>"char"</TD><TD>char</TD><TD>one character</TD></TR>
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</TABLE>
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</CENTER>
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</BLOCKQUOTE>
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<P>You will see the internal name when examining system catalogs
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and in some error messages.</P>
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