Consultor Eletrônico

What is PROLIB and how to use!!!

910730-cmb01
INTRODUCTION:
=============
This Progress Software Technical Support Knowledgebase entry
explains the functionality of the r-code librarian (PROLIB)
available with Version 6.2F of PROGRESS.


WHY YOU NEED TO DO THIS:
========================
Currently PROGRESS applications that use many compiled .r
files cause the system to search the native file system for
the .r files whenever these files are referenced. For large
applications, this results in large directories, long search
times for each R-code file, and many (expensive) open/close
operations on each file as it is used. This can result in a
heavy performance penalty for larger applications with many
separate R-code files. PROLIB is a facility that groups many
R-code files into a single file (called a library) where
PROGRESS can look to find R-code files. Having a single place
to look for R-code files eliminates the large directory and
open/close issues, since the library can open once and allow
for faster searches. There can be more than one active library,
since libraries are specified in the PROPATH variable (discussed
later). In addition, the temporary sort files that are used to
hold R-code that has been "swapped-out" of memory can be reduced
in size, since R-code read in from a library can easily be reread
from the same library.


PROLIB COMPONENT
================
PROLIB is a stand-alone utilty. The syntax is:

PROLIB <library-name>.pl <command> [<command>...]

where <library-name> is the name of the library and has a .pl
extension, and <command> is any of the commands listed below.
Use the .pl extension on the library name so that PROGRESS can
detect a library on the PROPATH by just examining its extension.
Commands that can be used with the PROLIB utility are:

1. -create
Creates a new library. It generates an error if the
library already exists, unless -nowarn is specified (see
below).
2. -add file [file...]
Adds the specified files to the library. A file may not
appear in the library more than once. If an error occurs
that causes the PROLIB command containing the -add to fail,
the resulting library is still correct, but may seem larger
than it should be. This is the result of the new file
actually being added to the end of the library file, without
the directory being updated. (So, even though the bytes of
the new file are in the library, the library doesn't know
it). Running PROLIB with the -compress option will fix this
(see below).
3. -replace file [file...]
Replaces the specified file in the library. If you attempt
to replace a file that isn't already in the library, you get
an error (unless -nowarn is specified, see below).
4. -delete file [file...]
Deletes the specified files from the library.
5. -list [file...]
Lists the table of contents of the library, as well as
some other information about the library. The listing is
sorted by file name, and dates display in the format
specifed by the -date command.
6. -date date-format
Specifies the format of the date to use in displaying file
time stamps in the -list command. The format of "date-format"
is the same as that of the -d switch in PROGRESS. The
default value is "mdy".
7. -extract file [file...]
Extracts the named files from the library. The files are
copied from the library into files with the same names that
they were entered with. If PROLIB tries to extract a file that
would go in a directory that doesn't exist, it prompts for a
name that the file should be extracted as. Files extracted
retain the same modification time that they had when they were
added to the library, and the access time is set to the time
stamp of when the file was added to the library, on operating
systems that support this functionality. If a file being
extracted already exists outside of the library, it warns of
this and prompts for an action (overwrite, rename, quit), unless
you use -nowarn (see below).
8. -nowarn
This option, which takes effect for all commands on the command
line, causes the -add, -replace, -extract, -delete, and -create
options to do their work silently as described above.
9. -yank
This option works exactly like -extract except that any leading
pathname component is stripped off so that the resulting file
is placed in the current working directory.
10. -compress
Compresses the library by making a copy of it. The -compress
option creates a temp file named PLBXXXXXX (where the X's are
replaced by some number) in the current directory to
accomplish the compression.
11. -f file
This command allows you to supply command-line arguments in a
file. The contents of the specified file are inserted in the
command line replacing the"-f file" command. This allows
you to specify commands that would normally overflow the system
conname line length limits. A file of command line arguments
cannot itself contain a -f command.
12. -verbose
Normally, PROLIB does its work silently. This command directs
PROLIB to tell you what's being done as it's happening. This
is reassuring if you're doing multiple -add's (or -create's,
or -extract's) and want to be sure something is actually
taking place.


PROGRESS COMPONENT
==================
PROGRESS has been modified to search for R-code files in a library.
PROGRESS will not look for source code in a library. So, the
PROPATH variable can contain directory names, as well as library
names. Libraries can be named as fully qualified file names,
partially qualified file names, or as simple file names. All
libraries must have a ".pl" extension.

For those of you using networks, and whose libraries are
on the file servers, there is a PROGRESS switch (-pls) that
directs PROGRESS to use the conventional sort file technique for
library-based procedures. This way, if you have a local disk or a
RAM-disk that holds the sort file, it is faster to use the
sort file than to do the remote file server accesses to the
library.

Since using a library consumes available memory by keeping
the library available in memory, you may want to opt for reading
the library directory in from disk as needed, trading off some
speed for memory availability. The PROGRESS switch -plm causes
PROGRESS to use a 512 byte cache for the library directory,
rather than reading the entire directory in from memory.

If the PROPATH environment variable is changed during a PROGRESS
session, then any libraries that appeared on the old PROPATH but
not on the new one are closed. Any libraries that were on the old
PROPATH and the new one remain open.

Libraries are only opened as needed. If all requests for R-code
files are satisfied by directories earlier on the PROPATH than any
libraries, then no libraries are opened.


ISSUES
======
1. The PROGRESS "SEARCH" function returns the full path of a file
that may be found in a directory on the PROPATH. The syntax is:

SEARCH("pgm-name").

The function: name = SEARCH("dict.r") sets 'name'
equal to: "/usr/dlc/dictionary.pl<<dict.r>>" where
'dictionary.pl' is the library containing the dictionary
procedures.

2. The PROGRESS "LIBRARY" function takes a character string
argument and either return the library name that the string
mentions, or the unknown value if the argument doesn't denote
a library. In the above example, LIBRARY(name) would return
"/usr/dlc/dictionary.pl".

3. The PROGRESS MEMBER function returns the member for a name.
In the above example, MEMBER(name) would return "dict.r".

4. In PROGRESS, do not change the PROPATH during program
execution such that a library is removed form the PROPATH that
contains a file that is currently active (i.e. contains a
procedure that is currently running or is waiting for a
subprocedure to return).

5. If a library is opened indirectly, that is via a SEARCH or RUN
statement that generates a library name that is not on the
PROPATH, then that library will stay open forever (or until
the PROGRESS session is terminated).


MEMORY IMPACT
=============
Using the library requires memory for the library
directories, which are dynamically allocated. The command line
switch "-plm" allows you to opt for having the library
directories cached in small chunks (rather than being read in in
their entirety) in the event that PROGRESS fails due to memory
shortage when a library is used. This cache incurs a 512
byte overhead.


REFERENCES TO WRITTEN DOCUMENTATION:
====================================
System Administration II: General, Chapter 4, page 4-24 - 4-33.

Progress Software Technical Support Note # 10045