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The PostgreSQL 9.0 Reference Manual - Volume 3 - Server Administration Guide
by The PostgreSQL Global Development Group
Paperback (6"x9"), 274 pages
ISBN 9781906966072
RRP £9.95 ($14.95)

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4.4.2 Kernel Resource Usage

max_files_per_process (integer)
Sets the maximum number of simultaneously open files allowed to each server subprocess. The default is one thousand files. If the kernel is enforcing a safe per-process limit, you don't need to worry about this setting. But on some platforms (notably, most BSD systems), the kernel will allow individual processes to open many more files than the system can actually support if many processes all try to open that many files. If you find yourself seeing “Too many open files” failures, try reducing this setting. This parameter can only be set at server start.
shared_preload_libraries (string)
This variable specifies one or more shared libraries to be preloaded at server start. For example, '$libdir/mylib' would cause mylib.so (or on some platforms, mylib.sl) to be preloaded from the installation's standard library directory. All library names are converted to lower case unless double-quoted. If more than one library is to be loaded, separate their names with commas. This parameter can only be set at server start. PostgreSQL procedural language libraries can be preloaded in this way, typically by using the syntax '$libdir/plXXX' where XXX is pgsql, perl, tcl, or python. By preloading a shared library, the library startup time is avoided when the library is first used. However, the time to start each new server process might increase slightly, even if that process never uses the library. So this parameter is recommended only for libraries that will be used in most sessions.

Note: On Windows hosts, preloading a library at server start will not reduce the time required to start each new server process; each server process will re-load all preload libraries. However, shared_preload_libraries is still useful on Windows hosts because some shared libraries may need to perform certain operations that only take place at postmaster start (for example, a shared library may need to reserve lightweight locks or shared memory and you can't do that after the postmaster has started).

If a specified library is not found, the server will fail to start. Every PostgreSQL-supported library has a “magic block” that is checked to guarantee compatibility. For this reason, non-PostgreSQL libraries cannot be loaded in this way.
ISBN 9781906966072The PostgreSQL 9.0 Reference Manual - Volume 3 - Server Administration GuideSee the print edition