--- doc/build/Attic/loncapasqldatabase.html 2001/02/10 18:38:37 1.4 +++ doc/build/Attic/loncapasqldatabase.html 2001/02/13 12:53:43 1.7 @@ -8,13 +8,13 @@ Scott Harrison

-Last updated: 02/10/2001 +Last updated: 02/12/2001

This file describes issues associated with LON-CAPA and a SQL database.

-

Latest HOWTO

+

Latest HOWTO

-

Current status of documentation

+

Current status of documentation

I am going to begin documentation by inserting what notes I have into this file. I will be subsequently rearranging @@ -39,13 +39,24 @@ current status of everything is that it been minimally tested, but things need to be cleaned up and checked again!

-

Current status of implementation

+

Current status of implementation

+

+Need to +

Right now, a lot of "feasibility" work has been done. Recipes for manual installation and configuration have been gathered. Network connectivity of lond->lonsql->lond->lonc type tests have been performed. A binary installation -has been compiled in an RPM (LON-CAPA-mysql). +has been compiled in an RPM (LON-CAPA-mysql, with perl components +a part of LON-CAPA-systemperl). The most lacking test in terms of feasibility has been looking at benchmarks to analyze the load at which the SQL database can efficiently allow many users to @@ -70,7 +81,7 @@ to the point of getting this SQL softwar however there may be more optimal approaches than currently exist.

-

Purpose within LON-CAPA

+

Purpose within LON-CAPA

LON-CAPA is meant to distribute A LOT of educational content to A LOT of people. It is ineffective to directly rely on contents @@ -131,13 +142,14 @@ THE SOLUTION: processes (lonsql's) handle the MySQL database manipulations.

-

Installation

+

Installation

Installation of the LON-CAPA SQL database normally occurs by default when using the LON-CAPA installation CD (see http://install.lon-capa.org). It is installed as the LON-CAPA-mysql RPM. This RPM encodes for the MySQL -engine and related perl interfaces (Perl::DBI, Perl::Msql-Mysql). +engine. Related perl interfaces (Perl::DBI, Perl::Msql-Mysql) +are encoded in the LON-CAPA-systemperl RPM.

The three components of a MySQL installation for the @@ -160,7 +172,7 @@ from source or pre-compiled file listing actual MySQL functionality on the system

-

Installation from source

+

Installation from source

The following set of tarballs was found to work together properly on a LON-CAPA RedHat 6.2 system: @@ -174,13 +186,13 @@ properly on a LON-CAPA RedHat 6.2 system Installation was simply a matter of following the instructions and typing the several "make" commands for each

-

Configuration (automated)

+

Configuration (automated)

Not yet developed. This will be part of an interface present on LON-CAPA systems that can be launched by entering the command /usr/sbin/loncapaconfig.

-

Manual configuration

+

Manual configuration

This is not complete.

@@ -215,124 +227,9 @@ FLUSH PRIVILEGES; Copy support-files/mysql.server to the right place on the system (/etc/rc.d/...).

-

Testing

-

-Not yet documented or formalized. -

-

Example sections of code relevant to LON-CAPA

-

-

- -

Old notes

- -

How to add a user to the SQL database

-

-

-start the mysql daemon as /usr/local/bin/safe_mysqld &
-Login as root: mysql -u root -p mysql
-enter the password as newmysql
-add the user www: grant all priveleges on *.* to www@localhost identified by 'newmysql' with grant option;
-
-INSERT INTO user (Host, User, Password)
-VALUES ('localhost','www',password('newmysql'));
-
-GRANT ALL PRIVILEGES ON *.* TO www@localhost;
-
-FLUSH PRIVILEGES;
-
-Here the user www has the right to grant privileges to other users.
-This can be changed if required with a simple update command on the grant tables
-
-
-/home/httpd/perl/perlsql/lonsql
-/usr/local/mysql/fakeclient
-
-

-

To do

-

-

-This is the output from scripts/mysql_install_db...
-still some todo things (like support-files/mysql.server)
-
-Creating db table
-Creating host table
-Creating user table
-Creating func table
-Creating tables_priv table
-Creating columns_priv table
-
-To start mysqld at boot time you have to copy support-files/mysql.server
-to the right place for your system
-
-PLEASE REMEMBER TO SET A PASSWORD FOR THE MySQL root USER !
-This is done with:
-/usr/local/bin/mysqladmin -u root password 'new-password'
-See the manual for more instructions.
-
-Please report any problems with the /usr/local/bin/mysqlbug script!
-
-The latest information about MySQL is available on the web at http://www.mysql.com
-Support MySQL by buying support/licenses at http://www.tcx.se/license.htmy.
-
-

-

Source Installation and Manual Configuration

+The Perl API

-August, 29 2000; Scott Harrison; LON-CAPA
-
-These are notes related to a Perl interface and MySQL server installation
-on Redhat 6.1 and 6.2 boxes.  (Guy Albertelli and Harsha Jagasia
-contributed significantly to this.)
-
-********************
-* MySQL COMPONENTS *
-********************
-
-There are three components to an effective MySQL installation for the
-LON-CAPA system.
-
-Perl::DBI module- the API "front-end"...
-                  database interface module for organizing generic
-                  database commands which are independent of specific
-                  database implementation (such as MySQL, mSQL, Postgres, etc).
-
-Perl::MySQL module- the API "mid-section"...
-                    the module to directly interface with the actual
-                    MySQL database engine
-
-MySQL database engine- the "back-end"...
-                       the binary installation (compiled either from source
-                       or pre-compiled file listings) which provides the
-                       actual MySQL functionality on the system
-
-RedHat Installation-
-
-Initially done from source:
-DBI-1.13.tar.gz  Msql-Mysql-modules-1.2209.tar.gz  mysql-3.22.32.tar.gz
-
-I am now using pre-compiled file listings.
-
-There were problems with using the RedHat packages since the three
-different RedHat packages were somewhat noncompatible with each other
-in terms of expected file locations. (The Debian linux distribution,
-on the other hand, has a working set of these packages).
-
-Regardless of how we install these three components, there still remain
-certain things which need to happen for the configuration.
-
-*****************
-* CONFIGURATION *
-*****************
-
-(Note: SOMEPASSWORD is actually set to another text string on the current
-LON-CAPA systems.)
-
-Configuration is needed to generate the necessary functionality for the
-MySQL system with LON-CAPA.
-
-The functionality needed can be understood from this example line
-of perl code from "lonsql".
-
    $dbh = DBI->connect(	"DBI:mysql:loncapa",
 			"www",
 			"SOMEPASSWORD",
@@ -395,56 +292,28 @@ FLUSH PRIVILEGES;
 ** ABILITY for LON-CAPA machines to communicate with SQL databases on
    other LON-CAPA machines
 
-This is a little more intricate than might first be expected (and I probably
-won't do a perfect job reciting everything in this short synopsis).  Because
-LON-CAPA machines will likely be handling many SQL requests at a time,
-there were some problems with current MySQL capabilities.
-
-PROBLEM SITUATION:
-
-  If Server A wants data from Server B, Server A uses a lonc process to
-  send a database command to a Server B lond process.
-    lonc= loncapa client process    A-lonc= a lonc process on Server A
-    lond= loncapa daemon process
-
-                 database command
-    A-lonc  --------TCP/IP----------------> B-lond
-
-  The problem emerges that A-lonc and B-lond are kept waiting for the
-  MySQL server to "do its stuff", or in other words, perform the conceivably
-  sophisticated, data-intensive, time-sucking database transaction.  By tying
-  up a lonc and lond process, this significantly cripples the capabilities
-  of LON-CAPA servers. 
-
-  While commercial databases have a variety of features that ATTEMPT to
-  deal with this, freeware databases are still experimenting and exploring
-  with different schemes with varying degrees of performance stability.
-
-THE SOLUTION:
-
-  A separate daemon process was created that B-lond works with to
-  handle database requests.  This daemon process is called "lonsql".
-
-  So,
-                database command
-  A-lonc  ---------TCP/IP-----------------> B-lond =====> B-lonsql
-         <---------------------------------/                |
-           "ok, I'll get back to you..."                    |
-                                                            |
-                                                            /
-  A-lond  <-------------------------------  B-lonc   <======
-           "Guess what? I have the result!"
-
-  Of course, depending on success or failure, the messages may vary,
-  but the principle remains the same where a separate pool of children
-  processes (lonsql's) handle the MySQL database manipulations.
+An up-to-date lond and lonsql.
+
+

+

Testing

+

+

+** TEST the database connection with my current tester.pl code
+which mimics what command will eventually be sent through lonc.
 
+$reply=reply(
+    "querysend:SELECT * FROM general_information WHERE Id='AAAAA'",$lonID);
+
+

+

Example sections of code relevant to LON-CAPA

+

Here are excerpts of code which implement the above handling: - -**LONSQL - +

+

+

+**LONSQL
 A subroutine from "lonsql" which establishes a child process for handling
-database interactions.
+database interactions.
 
 sub make_new_child {
     my $pid;
@@ -536,14 +405,19 @@ sub make_new_child {
         exit;
     }
 }
-
-** LOND enabling of MySQL requestsw
-
-  This code is part of every lond child process in the way that it parses command request syntax
-  sent to it from lonc processes.  querysend corresponds to B-lonc sending the result of the query.
-  queryreply corresponds to B-lond indicating that it has received the request and will start the
-  database transaction (it returns "ok" to A-lonc ($client)).
-
+

+

+** LOND enabling of MySQL requests +
+This code is part of every lond child process in the +way that it parses command request syntax sent to it +from lonc processes. Based on the diagram above, querysend +corresponds to B-lonc sending the result of the query. +queryreply corresponds to B-lond indicating that it has +received the request and will start the database transaction +(it returns "ok" to +A-lonc ($client)). +

 # ------------------------------------------------------------------- querysend
                    } elsif ($userinput =~ /^querysend/) {
                        my ($cmd,$query)=split(/:/,$userinput);
@@ -563,14 +437,8 @@ sub make_new_child {
 			   print $client "error:$!\n";
 		       }
 
-
-
-** TEST the database connection with my current tester.pl code which mimics what command will eventually be
-   sent through lonc.
-
-$reply=reply(
-    "querysend:SELECT * FROM general_information WHERE Id='AAAAA'",$lonID);
 
+