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| -rw-r--r-- | doc/FAQ | 72 | ||||
| -rw-r--r-- | doc/src/FAQ/FAQ.html | 76 |
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@@ -1,7 +1,7 @@ Frequently Asked Questions (FAQ) for PostgreSQL - Last updated: Sat Jan 29 22:51:43 EST 2005 + Last updated: Sat Jan 29 22:59:12 EST 2005 Current maintainer: Bruce Momjian (pgman@candle.pha.pa.us) @@ -38,20 +38,14 @@ 3.1) How do I install PostgreSQL somewhere other than /usr/local/pgsql? - 3.2) When I start postmaster, I get a Bad System Call or core dumped - message. Why? - 3.3) When I try to start postmaster, I get IpcMemoryCreate errors. - Why? - 3.4) When I try to start postmaster, I get IpcSemaphoreCreate errors. - Why? - 3.5) How do I control connections from other hosts? - 3.6) How do I tune the database engine for better performance? - 3.7) What debugging features are available? - 3.8) Why do I get "Sorry, too many clients" when trying to connect? - 3.9) What is in the pgsql_tmp directory? - 3.10) Why do I need to do a dump and restore to upgrade PostgreSQL + 3.2) How do I control connections from other hosts? + 3.3) How do I tune the database engine for better performance? + 3.4) What debugging features are available? + 3.5) Why do I get "Sorry, too many clients" when trying to connect? + 3.6) What is in the pgsql_tmp directory? + 3.7) Why do I need to do a dump and restore to upgrade PostgreSQL releases? - 3.11) What computer hardware should I use? + 3.8) What computer hardware should I use? Operational Questions @@ -419,43 +413,7 @@ Specify the --prefix option when running configure. - 3.2) When I start postmaster, I get a Bad System Call or core dumped - message. Why? - - It could be a variety of problems, but first check to see that you - have System V extensions installed in your kernel. PostgreSQL requires - kernel support for shared memory and semaphores. - - 3.3) When I try to start postmaster, I get IpcMemoryCreate errors. Why? - - You either do not have shared memory configured properly in your - kernel or you need to enlarge the shared memory available in the - kernel. The exact amount you need depends on your architecture and how - many buffers and backend processes you configure for postmaster. For - most systems, with default numbers of buffers and processes, you need - a minimum of ~1 MB. See the PostgreSQL Administrator's Guide/Server - Run-time Environment/Managing Kernel Resources section for more - detailed information about shared memory and semaphores. - - 3.4) When I try to start postmaster, I get IpcSemaphoreCreate errors. Why? - - If the error message is IpcSemaphoreCreate: semget failed (No space - left on device) then your kernel is not configured with enough - semaphores. Postgres needs one semaphore per potential backend - process. A temporary solution is to start postmaster with a smaller - limit on the number of backend processes. Use -N with a parameter less - than the default of 32. A more permanent solution is to increase your - kernel's SEMMNS and SEMMNI parameters. - - Inoperative semaphores can also cause crashes during heavy database - access. - - If the error message is something else, you might not have semaphore - support configured in your kernel at all. See the PostgreSQL - Administrator's Guide for more detailed information about shared - memory and semaphores. - - 3.5) How do I control connections from other hosts? + 3.2) How do I control connections from other hosts? By default, PostgreSQL only allows connections from the local machine using Unix domain sockets or TCP/IP connections. Other machines will @@ -463,7 +421,7 @@ postgresql.conf and enable host-based authentication by modifying the file $PGDATA/pg_hba.conf accordingly. - 3.6) How do I tune the database engine for better performance? + 3.3) How do I tune the database engine for better performance? Certainly, indexes can speed up queries. The EXPLAIN ANALYZE command allows you to see how PostgreSQL is interpreting your query, and which @@ -495,7 +453,7 @@ You can also use the CLUSTER command to group data in tables to match an index. See the CLUSTER manual page for more details. - 3.7) What debugging features are available? + 3.4) What debugging features are available? PostgreSQL has several features that report status information that can be valuable for debugging purposes. @@ -550,7 +508,7 @@ log_* in the client's current directory. Linux requires a compile with -DLINUX_PROFILE for proper profiling. - 3.8) Why do I get "Sorry, too many clients" when trying to connect? + 3.5) Why do I get "Sorry, too many clients" when trying to connect? You need to increase postmaster's limit on how many concurrent backend processes it can start. @@ -570,7 +528,7 @@ log_* that PostgreSQL has a limit on the number of allowed backend processes is so your system won't run out of resources. - 3.9) What is in the pgsql_tmp directory? + 3.6) What is in the pgsql_tmp directory? This directory contains temporary files generated by the query executor. For example, if a sort needs to be done to satisfy an ORDER @@ -581,7 +539,7 @@ log_* remain if a backend crashes during a sort. A stop and restart of the postmaster will remove files from those directories. - 3.10) Why do I need to do a dump and restore to upgrade between major + 3.7) Why do I need to do a dump and restore to upgrade between major PostgreSQL releases? The PostgreSQL team makes only small changes between minor releases, @@ -596,7 +554,7 @@ log_* script can be used to upgrade without a dump/restore. The release notes mention whether pg_upgrade is available for the release. - 3.11) What computer hardware should I use? + 3.8) What computer hardware should I use? Because PC hardware is mostly compatible, people tend to believe that all PC hardware is of equal quality. It is not. ECC RAM, SCSI, and diff --git a/doc/src/FAQ/FAQ.html b/doc/src/FAQ/FAQ.html index 797b708f8f8..b7e62d9f1fe 100644 --- a/doc/src/FAQ/FAQ.html +++ b/doc/src/FAQ/FAQ.html @@ -10,7 +10,7 @@ alink="#0000ff"> <H1>Frequently Asked Questions (FAQ) for PostgreSQL</H1> - <P>Last updated: Sat Jan 29 22:51:43 EST 2005</P> + <P>Last updated: Sat Jan 29 22:59:12 EST 2005</P> <P>Current maintainer: Bruce Momjian (<A href= "mailto:pgman@candle.pha.pa.us">pgman@candle.pha.pa.us</A>)<BR> @@ -56,24 +56,18 @@ <H2 align="center">Administrative Questions</H2> <A href="#3.1">3.1</A>) How do I install PostgreSQL somewhere other than <I>/usr/local/pgsql</I>?<BR> - <A href="#3.2">3.2</A>) When I start <I>postmaster</I>, I get a - <I>Bad System Call</I> or core dumped message. Why?<BR> - <A href="#3.3">3.3</A>) When I try to start <I>postmaster</I>, I - get <I>IpcMemoryCreate</I> errors. Why?<BR> - <A href="#3.4">3.4</A>) When I try to start <I>postmaster</I>, I - get <I>IpcSemaphoreCreate</I> errors. Why?<BR> - <A href="#3.5">3.5</A>) How do I control connections from other + <A href="#3.2">3.2</A>) How do I control connections from other hosts?<BR> - <A href="#3.6">3.6</A>) How do I tune the database engine for + <A href="#3.3">3.3</A>) How do I tune the database engine for better performance?<BR> - <A href="#3.7">3.7</A>) What debugging features are available?<BR> - <A href="#3.8">3.8</A>) Why do I get <I>"Sorry, too many + <A href="#3.4">3.4</A>) What debugging features are available?<BR> + <A href="#3.5">3.5</A>) Why do I get <I>"Sorry, too many clients"</I> when trying to connect?<BR> - <A href="#3.9">3.9</A>) What is in the <I>pgsql_tmp</I> + <A href="#3.6">3.6</A>) What is in the <I>pgsql_tmp</I> directory?<BR> - <A href="#3.10">3.10</A>) Why do I need to do a dump and restore + <A href="#3.7">3.7</A>) Why do I need to do a dump and restore to upgrade PostgreSQL releases?<BR> - <A href="#3.11">3.11</A>) What computer hardware should I use?<BR> + <A href="#3.8">3.8</A>) What computer hardware should I use?<BR> <H2 align="center">Operational Questions</H2> @@ -544,47 +538,7 @@ <P>Specify the <I>--prefix</I> option when running <I>configure</I>.</P> - <H4><A name="3.2">3.2</A>) When I start <I>postmaster</I>, I get a - <I>Bad System Call</I> or core dumped message. Why?</H4> - - <P>It could be a variety of problems, but first check to see that - you have System V extensions installed in your kernel. PostgreSQL - requires kernel support for shared memory and semaphores.</P> - - <H4><A name="3.3">3.3</A>) When I try to start <I>postmaster</I>, I - get <I>IpcMemoryCreate</I> errors. Why?</H4> - - <P>You either do not have shared memory configured properly in your - kernel or you need to enlarge the shared memory available in the - kernel. The exact amount you need depends on your architecture and - how many buffers and backend processes you configure for - <I>postmaster</I>. For most systems, with default numbers of - buffers and processes, you need a minimum of ~1 MB. See the <A - href="http://www.postgresql.org/docs/current/static/kernel-resources.html">PostgreSQL - Administrator's Guide/Server Run-time Environment/Managing Kernel Resources</A> - section for more detailed information about shared memory and semaphores.</P> - - <H4><A name="3.4">3.4</A>) When I try to start <I>postmaster</I>, I - get <I>IpcSemaphoreCreate</I> errors. Why?</H4> - - <P>If the error message is <I>IpcSemaphoreCreate: semget failed (No - space left on device)</I> then your kernel is not configured with - enough semaphores. Postgres needs one semaphore per potential - backend process. A temporary solution is to start <I>postmaster</I> - with a smaller limit on the number of backend processes. Use - <I>-N</I> with a parameter less than the default of 32. A more - permanent solution is to increase your kernel's - <SMALL>SEMMNS</SMALL> and <SMALL>SEMMNI</SMALL> parameters.</P> - - <P>Inoperative semaphores can also cause crashes during heavy - database access.</P> - - <P>If the error message is something else, you might not have - semaphore support configured in your kernel at all. See the - PostgreSQL Administrator's Guide for more detailed information - about shared memory and semaphores.</P> - - <H4><A name="3.5">3.5</A>) How do I control connections from other + <H4><A name="3.2">3.2</A>) How do I control connections from other hosts?</H4> <P>By default, PostgreSQL only allows connections from the local @@ -594,7 +548,7 @@ host-based authentication by modifying the file <I>$PGDATA/pg_hba.conf</I> accordingly.</P> - <H4><A name="3.6">3.6</A>) How do I tune the database engine for + <H4><A name="3.3">3.3</A>) How do I tune the database engine for better performance?</H4> <P>Certainly, indexes can speed up queries. The @@ -633,7 +587,7 @@ data in tables to match an index. See the <SMALL>CLUSTER</SMALL> manual page for more details.</P> - <H4><A name="3.7">3.7</A>) What debugging features are + <H4><A name="3.4">3.4</A>) What debugging features are available?</H4> <P>PostgreSQL has several features that report status information @@ -691,7 +645,7 @@ file will be put in the client's current directory. Linux requires a compile with <I>-DLINUX_PROFILE</I> for proper profiling.</P> - <H4><A name="3.8">3.8</A>) Why do I get <I>"Sorry, too many + <H4><A name="3.5">3.5</A>) Why do I get <I>"Sorry, too many clients"</I> when trying to connect?</H4> <P>You need to increase <I>postmaster</I>'s limit on how many @@ -716,7 +670,7 @@ the number of allowed backend processes is so your system won't run out of resources.</P> - <H4><A name="3.9">3.9</A>) What is in the <I>pgsql_tmp</I> directory?</H4> + <H4><A name="3.6">3.6</A>) What is in the <I>pgsql_tmp</I> directory?</H4> <P>This directory contains temporary files generated by the query executor. For example, if a sort needs to be done to satisfy an @@ -728,7 +682,7 @@ remain if a backend crashes during a sort. A stop and restart of the <I>postmaster</I> will remove files from those directories.</P> - <H4><A name="3.10">3.10</A>) Why do I need to do a dump and restore + <H4><A name="3.7">3.7</A>) Why do I need to do a dump and restore to upgrade between major PostgreSQL releases?</H4> <P>The PostgreSQL team makes only small changes between minor releases, @@ -744,7 +698,7 @@ The release notes mention whether <I>pg_upgrade</I> is available for the release.</P> - <H4><A name="3.11">3.11</A>) What computer hardware should I use?</H4> + <H4><A name="3.8">3.8</A>) What computer hardware should I use?</H4> <P>Because PC hardware is mostly compatible, people tend to believe that all PC hardware is of equal quality. It is not. ECC RAM, SCSI, and |