From 9f1e864d02ed4ec57105e531815ac7c113963559 Mon Sep 17 00:00:00 2001
From: Bruce Momjian <bruce@momjian.us>
Date: Sat, 23 Apr 2005 18:57:46 +0000
Subject: Add item about server-side debugging.

---
 doc/src/FAQ/FAQ_DEV.html | 43 ++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 42 insertions(+), 1 deletion(-)

(limited to 'doc/src')

diff --git a/doc/src/FAQ/FAQ_DEV.html b/doc/src/FAQ/FAQ_DEV.html
index 111fb12a0c8..a9ef832f29a 100644
--- a/doc/src/FAQ/FAQ_DEV.html
+++ b/doc/src/FAQ/FAQ_DEV.html
@@ -13,7 +13,7 @@
     <H1>Developer's Frequently Asked Questions (FAQ) for
     PostgreSQL</H1>
 
-    <P>Last updated: Sun Mar 13 22:07:18 EST 2005</P>
+    <P>Last updated: Sat Apr 23 14:57:40 EDT 2005</P>
 
     <P>Current maintainer: Bruce Momjian (<A href=
     "mailto:pgman@candle.pha.pa.us">pgman@candle.pha.pa.us</A>)<BR>
@@ -71,6 +71,8 @@
     <I>pfree</I>() to allocate memory?<BR>
      <A href="#2.6">2.6</A>) What is ereport()?<BR>
      <A href="#2.7">2.7</A>) What is CommandCounterIncrement()?<BR>
+     <A href="#2.8">2.8</A>) What debugging features are available?<BR>
+
      <BR>
      
     <HR>
@@ -941,6 +943,45 @@
     modified by previous pieces. <I>CommandCounterIncrement()</I>
     increments the Command Counter, creating a new part of the
     transaction.</P>
+
+    <H3><A name="2.8">2.8</A>) What debugging features are
+    available?</H3>
+
+    <P>First, try running <I>configure</I> with the --enable-cassert
+    option, many <I>assert()</I>s monitor the progress of the backend
+    and halt the program when something unexpected occurs.</P>
+
+    <P>The <I>postmaster</I> has a <I>-d</I> option that allows even more
+    detailed information to be reported. The <I>-d</I> option takes a
+    number that specifies the debug level. Be warned that high debug
+    level values generate large log files.</P>
+
+    <P>If the <I>postmaster</I> is not running, you can actually run the
+    <I>postgres</I> backend from the command line, and type your
+    <SMALL>SQL</SMALL> statement directly. This is recommended
+    <B>only</B> for debugging purposes. If you have compiled with debugging
+    symbols, you can use a debugger to see what is happening. Because
+    the backend was not started from <I>postmaster</I>, it is not
+    running in an identical environment and locking/backend interaction
+    problems may not be duplicated.</P>
+
+    <P>If the <I>postmaster</I> is running, start <I>psql</I> in one
+    window, then find the <SMALL>PID</SMALL> of the <I>postgres</I>
+    process used by <I>psql</I> using <CODE>SELECT pg_backend_pid()</CODE>.
+    Use a debugger to attach to the <I>postgres</I> <SMALL>PID</SMALL>.
+    You can set breakpoints in the debugger and issue queries from
+
+    <I>psql</I>. If you are debugging <I>postgres</I> startup, you can
+    set PGOPTIONS="-W n", then start <I>psql</I>. This will cause startup
+    to delay for <I>n</I> seconds so you can attach to the process with
+    the debugger, set any breakpoints, and continue through the startup
+    sequence.</P>
+
+    <P>You can also compile with profiling to see what functions are
+    taking execution time. The backend profile files will be deposited
+    in the <I>pgsql/data/base/dbname</I> directory. The client profile
+    file will be put in the client's current directory. Linux requires
+    a compile with <I>-DLINUX_PROFILE</I> for proper profiling.</P>
   </BODY>
 </HTML>
 
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