> I can see a couple possible downsides: (a) the library might have some
> weird behavior across fork boundaries; (b) the additional memory space > that has to be duplicated into child processes will cost something per > child launch, even if the child never uses it. But these are only > arguments that it might not *always* be a prudent thing to do, not that > we shouldn't give the DBA the tool to do it if he wants. So fire away. Here is a patch for the above, including a documentation update. It creates a new GUC variable "preload_libraries", that accepts a list in the form: preload_libraries = '$libdir/mylib1:initfunc,$libdir/mylib2' If ":initfunc" is omitted or not found, no initialization function is executed, but the library is still preloaded. If "$libdir/mylib" isn't found, the postmaster refuses to start. In my testing with PL/R, it reduces the first call to a PL/R function (after connecting) from almost 2 seconds, down to about 8 ms. Joe Conway
This commit is contained in:
Bruce Momjian
parent
e733510d5d
commit
15ce2d2e4a
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@ -1,5 +1,5 @@
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<!--
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$Header: /cvsroot/pgsql/doc/src/sgml/runtime.sgml,v 1.171 2003/03/20 03:34:55 momjian Exp $
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$Header: /cvsroot/pgsql/doc/src/sgml/runtime.sgml,v 1.172 2003/03/20 04:51:44 momjian Exp $
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-->
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<Chapter Id="runtime">
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@ -1799,6 +1799,35 @@ dynamic_library_path = '/usr/local/lib/postgresql:/home/my_project/lib:$libdir'
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>PRELOAD_LIBRARIES</varname> (<type>string</type>)</term>
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<indexterm><primary>preload_libraries</></>
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<listitem>
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<para>
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This variable specifies one or more shared libraries that are to be
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preloaded at Postmaster start. An initialization function can also be
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optionally specified by adding a colon followed by the name of the
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initialization function after the library name. For example
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<literal>'$libdir/mylib:init_mylib'</literal> would cause <literal>mylib</>
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to be preloaded and <literal>init_mylib</> to be executed. If more than
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one library is to be loaded, they must be delimited with a comma.
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</para>
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<para>
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If <literal>mylib</> is not found, the postmaster will fail to start.
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However, if <literal>init_mylib</> is not found, <literal>mylib</> will
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still be preloaded without executing the initialization function.
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</para>
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<para>
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By preloading a shared library (and initializing it if applicable),
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the library startup time is avoided when the library is used later in a
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specific backend. However there is a cost in terms of memory duplication
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as every backend is forked, whether or not the library is used.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>REGEX_FLAVOR</varname> (<type>string</type>)</term>
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<indexterm><primary>regular expressions</></>
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@ -37,7 +37,7 @@
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*
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/postmaster/postmaster.c,v 1.307 2003/02/23 04:48:19 tgl Exp $
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* $Header: /cvsroot/pgsql/src/backend/postmaster/postmaster.c,v 1.308 2003/03/20 04:51:44 momjian Exp $
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*
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* NOTES
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*
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@ -205,6 +205,8 @@ bool LogSourcePort;
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bool Log_connections = false;
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bool Db_user_namespace = false;
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/* list of library:init-function to be preloaded */
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char *preload_libraries_string = NULL;
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/* Startup/shutdown state */
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static pid_t StartupPID = 0,
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@ -645,6 +647,13 @@ PostmasterMain(int argc, char *argv[])
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secure_initialize();
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#endif
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/*
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* process any libraries that should be preloaded and
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* optionally pre-initialized
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*/
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if (preload_libraries_string)
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process_preload_libraries(preload_libraries_string);
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/*
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* Fork away from controlling terminal, if -S specified.
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*
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@ -8,7 +8,7 @@
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*
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/utils/init/miscinit.c,v 1.100 2003/01/27 00:51:06 tgl Exp $
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* $Header: /cvsroot/pgsql/src/backend/utils/init/miscinit.c,v 1.101 2003/03/20 04:51:44 momjian Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -1044,3 +1044,92 @@ ValidatePgVersion(const char *path)
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"which is not compatible with this version %s.",
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file_major, file_minor, version_string);
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}
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/*-------------------------------------------------------------------------
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* Library preload support
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*-------------------------------------------------------------------------
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*/
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#if defined(__mc68000__) && defined(__ELF__)
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typedef int32 ((*func_ptr) ());
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#else
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typedef char *((*func_ptr) ());
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#endif
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/*
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* process any libraries that should be preloaded and
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* optionally pre-initialized
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*/
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void
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process_preload_libraries(char *preload_libraries_string)
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{
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char *rawstring;
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List *elemlist;
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List *l;
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if (preload_libraries_string == NULL)
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return;
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/* Need a modifiable copy of string */
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rawstring = pstrdup(preload_libraries_string);
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/* Parse string into list of identifiers */
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if (!SplitIdentifierString(rawstring, ',', &elemlist))
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{
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/* syntax error in list */
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pfree(rawstring);
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freeList(elemlist);
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elog(LOG, "invalid list syntax for preload_libraries configuration option");
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}
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foreach(l, elemlist)
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{
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char *tok = (char *) lfirst(l);
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char *sep = strstr(tok, ":");
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char *filename = NULL;
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char *funcname = NULL;
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func_ptr initfunc;
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if (sep)
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{
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/*
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* a colon separator implies there is an initialization function
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* that we need to run in addition to loading the library
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*/
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size_t filename_len = sep - tok;
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size_t funcname_len = strlen(tok) - filename_len - 1;
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filename = (char *) palloc(filename_len + 1);
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memset(filename, '\0', filename_len + 1);
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snprintf(filename, filename_len + 1, "%s", tok);
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funcname = (char *) palloc(funcname_len + 1);
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memset(funcname, '\0', funcname_len + 1);
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snprintf(funcname, funcname_len + 1, "%s", sep + 1);
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}
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else
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{
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/*
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* no separator -- just load the library
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*/
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filename = pstrdup(tok);
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funcname = NULL;
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}
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initfunc = (func_ptr) load_external_function(filename, funcname, false, NULL);
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if (initfunc)
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(*initfunc)();
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elog(LOG, "preloaded library %s with initialization function %s", filename, funcname);
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if (filename != NULL)
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pfree(filename);
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if (funcname != NULL)
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pfree(funcname);
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}
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pfree(rawstring);
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freeList(elemlist);
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}
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@ -5,7 +5,7 @@
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* command, configuration file, and command line options.
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* See src/backend/utils/misc/README for more information.
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*
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* $Header: /cvsroot/pgsql/src/backend/utils/misc/guc.c,v 1.116 2003/03/04 21:51:21 tgl Exp $
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* $Header: /cvsroot/pgsql/src/backend/utils/misc/guc.c,v 1.117 2003/03/20 04:51:44 momjian Exp $
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*
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* Copyright 2000 by PostgreSQL Global Development Group
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* Written by Peter Eisentraut <peter_e@gmx.net>.
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@ -60,6 +60,7 @@ extern int CheckPointTimeout;
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extern bool autocommit;
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extern int CommitDelay;
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extern int CommitSiblings;
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extern char *preload_libraries_string;
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#ifdef HAVE_SYSLOG
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extern char *Syslog_facility;
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@ -814,6 +815,12 @@ static struct config_string
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"C", locale_time_assign, NULL
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},
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{
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{"preload_libraries", PGC_POSTMASTER, GUC_LIST_INPUT | GUC_LIST_QUOTE},
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&preload_libraries_string,
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"", NULL, NULL
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},
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{
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{"regex_flavor", PGC_USERSET}, ®ex_flavor_string,
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"advanced", assign_regex_flavor, NULL
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@ -214,4 +214,5 @@
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#transform_null_equals = false
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#statement_timeout = 0 # 0 is disabled, in milliseconds
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#db_user_namespace = false
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#preload_libraries = ''
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@ -12,7 +12,7 @@
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* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* $Id: miscadmin.h,v 1.116 2003/02/22 05:57:45 tgl Exp $
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* $Id: miscadmin.h,v 1.117 2003/03/20 04:51:44 momjian Exp $
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*
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* NOTES
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* some of the information in this file should be moved to
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@ -288,6 +288,7 @@ extern void RecordSharedMemoryInLockFile(unsigned long id1,
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unsigned long id2);
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extern void ValidatePgVersion(const char *path);
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extern void process_preload_libraries(char *preload_libraries_string);
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/* these externs do not belong here... */
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extern void IgnoreSystemIndexes(bool mode);
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Loading…
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