--- doc/build/Attic/loncapasqldatabase.html 2001/02/10 18:38:37 1.4 +++ doc/build/Attic/loncapasqldatabase.html 2001/02/20 22:24:45 1.15 @@ -8,18 +8,20 @@ Scott Harrison

-Last updated: 02/10/2001 +Last updated: 02/15/2001

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

-

Latest HOWTO

+

Latest HOWTO

-

Current status of documentation

+

Important notes

+

+The current database is implemented assuming a non-adjustable +architecture involving these data fields (specific to each version +of a resource). +

+

+

+Security occurs as a function of the user 'www', +and the permissions on the files in the /usr/local/mysql +directory. (These files and directories should +be 700, 600, 500, 400, etc; not allow access to anyone +but user 'www'.) +

+

+These commands create the loncapameta database. +

+mysql> CREATE DATABASE IF NOT EXISTS loncapa;
+mysql> USE loncapa;
+mysql> CREATE TABLE IF NOT EXISTS metadata (title TEXT, author TEXT, subject TEXT, notes TEXT, abstract TEXT, mime TEXT, language TEXT, creationdate TEXT, lastrevisiondate TEXT, owner TEXT, copyright TEXT, FULLTEXT idx_title (title), FULLTEXT idx_author (author), FULLTEXT idx_subject (subject), FULLTEXT idx_notes (notes), FULLTEXT idx_abstract (abstract), FULLTEXT idx_mime (mime), FULLTEXT idx_language (language), FULLTEXT idx_creationdate (creationdate), FULLTEXT idx_lastrevisiondate (lastrevisiondate), FULLTEXT idx_owner (owner), FULLTEXT idx_copyright (copyright)) TYPE=MYISAM;
+mysql> INSERT INTO metadata VALUES ('1','2','3','4','5','6','7','8','9','10','11');
+mysql> SELECT * FROM metadata WHERE title REGEXP "1";
+
+

+

+Current time values for things. +

+fenchurch.lite.msu.edu
+Mem:    46812K av,   45632K used,    1180K free,   14756K shrd,    4292K buff
+Swap: 1148608K av,   11260K used, 1137348K free                   13244K cached
+
+Red Hat Linux release 6.2 (Zoot)
+Kernel 2.2.16-3 on an i586
+
+
Q: How big are data records in test database? A: on average, 1000 bytes each, medline records from PubMed. +
Q: How big is the biggest field? A: on average, 838 bytes each +
Q: How much time to insert 5284 medline records into database? +A: 600 seconds +
Q: What about when using "speed-technique" on page 130? A: 689 seconds (weird, eh?) +
Q: What about REGEXP searching? A: about 1-2 seconds for small fields; +10 to 20 seconds for REGEXP search on "abstract" field +
Q: What about FULLTEXT indexing? A: about 6 seconds for abstract field. + +

+

+An important quote from the manual: +

+In MySQL Version 3.23.23 or later, you can also create special FULLTEXT indexes. They are used for full-text search. Only the MyISAM table type supports FULLTEXT indexes. They can be created only from +VARCHAR and TEXT columns. Indexing always happens over the entire column and partial indexing is not supported. See section 25.2 MySQL Full-text Search for details. +
+

+

+I plan on using a MyISAM table type with 11 metadata fields of column +type=TEXT. +

+

+It might be worthwhile to look at /usr/local/mysql/manual.html. +It is quite in depth. +

+

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 +112,24 @@ 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 +154,7 @@ 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 +215,31 @@ THE SOLUTION: processes (lonsql's) handle the MySQL database manipulations.

-

Installation

+

Dependencies

+

+I believe (but am not 100% confident) that the following +RPMs are necessary (in addition to the current ones +in rpm_list.txt) to run MySQL. Basically I discovered these +dependencies while trying to do external RPM based installs. +I assume, and sometimes found, that these dependencies apply +to tarball-based distributions too. (So to play it on the +safe side, I am going to include these RPMs as part of the +core, minimal RPM set.) +

+

+

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 +262,254 @@ from source or pre-compiled file listing actual MySQL functionality on the system

-

Installation from source

+

Installation from source

+

+Note: the mysql site recommends that Linux users install by +using the MySQL RPMs (MySQL-client, MySQL, MySQL-shared, etc). +While these RPMs work, I was unsuccessful at integrating +this RPM-installed database with perl modules from www.cpan.org. +Hence, I strongly recommend that, when installing +from "source", MySQL and the perl components be in fact installed +from their tarballs (.tar.gz, .tgz). (Perl components, when installed +from RPMs, also wound up in incorrect locations on the disk.) +Do not coordinate a source install with externally made RPMs! +It is, of course, okay to use LON-CAPA RPMs such as LON-CAPA-systemperl +and LON-CAPA-mysql since we, in fact, made these RPMs correctly :). +

+

+

So, here is exactly how I installed MySQL-3.23. (Note that all files +wind up in /usr/local/mysql-3.23.33-pc-linux-gnu-i686 except for +a link from /usr/local/mysql to /usr/local/mysql-3.23.33-pc-linux-gnu-i686 +and some files involved in system process handling (/etc/rc.d/*/*mysql). +

+(As user=root)
+cd /usr/local/;
+tar xzvf mysql-3.23.33-pc-linux-gnu-i686.tar.gz
+ln -s /usr/local/mysql-3.23.33-pc-linux-gnu-i686 mysql
+cd /usr/local/mysql
+chown -R www /usr/local/mysql/.
+chgrp -R users /usr/local/mysql/.
+chmod -R g-w,g-r,g-x /usr/local/mysql/.
+(probably also want chmod -R a-w,a-r,a-x /usr/local/mysql/.)
+
+Alter safe_mysqld
+and support-files/mysql.server to use 'localhosts' instead
+of `bin/hostname`.  Also, to use user 'www' instead of 'mysql'.
+
+(These changes could be done with /etc/my.cnf, but
+I think this approach makes sure the database NEVER
+gets screwed up due to somebody forgetting to install /etc/my.cnf).
+
+Change this line in mysql.server from
+  pid_file=$datadir/`@HOSTNAME@`.pid
+to
+  pid_file=$datadir/localhost.pid
+
+Change this line in safe_mysqld from
+user=root
+to
+user=www
+
+Change this line in safe_mysqld from
+  pid_file=$DATADIR/`/bin/hostname`.pid
+to
+  pid_file=$DATADIR/localhost.pid
+
+Change this line in safe_mysqld from
+test -z "$err_log"  && err_log=$DATADIR/`/bin/hostname`.err
+to
+test -z "$err_log"  && err_log=$DATADIR/localhost.err
+
+cp -p support-files/mysql.server /etc/rc.d/init.d/mysql
+chmod 755 /etc/rc.d/init.d/mysql
+/sbin/chkconfig --add mysql
+/etc/rc.d/init.d/mysql start
+
+
+

+

This is how I installed the Msql-Mysql-modules perl modules. +

+[root@fenchurch Msql-Mysql-modules-1.2215]# perl Makefile.PL 
+Which drivers do you want to install?
+
+    1)	MySQL only
+    2)	mSQL only (either of mSQL 1 or mSQL 2)
+    3)  MySQL and mSQL (either of mSQL 1 or mSQL 2)
+
+    4)  mSQL 1 and mSQL 2
+    5)  MySQL, mSQL 1 and mSQL 2
+
+Enter the appropriate number:  [3] 1
+
+
+Do you want to install the MysqlPerl emulation? You might keep your old
+Mysql module (to be distinguished from DBD::mysql!) if you are concerned
+about compatibility to existing applications! [y] n
+Where is your MySQL installed? Please tell me the directory that
+contains the subdir 'include'. [/usr/local/mysql] 
+Which database should I use for testing the MySQL drivers? [test] 
+On which host is database test running (hostname, ip address
+or host:port) [localhost] 
+User name for connecting to database test? [undef]
+Password for connecting to database test? [undef]
+[root@fenchurch Msql-Mysql-modules-1.2215]# make
+[root@fenchurch Msql-Mysql-modules-1.2215]# make test
+make[1]: Entering directory `/home/user/Msql-Mysql-modules-1.2215/mysql'
+make[1]: Leaving directory `/home/user/Msql-Mysql-modules-1.2215/mysql'
+make[1]: Entering directory `/home/user/Msql-Mysql-modules-1.2215/mysql'
+PERL_DL_NONLAZY=1 /usr/bin/perl -I../blib/arch -I../blib/lib -I/usr/lib/perl5/5.00503/i386-linux -I/usr/lib/perl5/5.00503 -e 'use Test::Harness qw(&runtests $verbose); $verbose=0; runtests @ARGV;' t/*.t
+t/00base............ok
+t/10dsnlist.........ok
+t/20createdrop......ok
+t/30insertfetch.....ok
+t/40bindparam.......ok
+t/40blobs...........ok
+t/40listfields......ok
+t/40nulls...........ok
+t/40numrows.........ok
+t/50chopblanks......ok
+t/50commit..........ok
+t/60leaks...........skipping test on this platform
+t/ak-dbd............ok
+t/akmisc............ok
+t/dbdadmin..........ok
+t/mysql.............ok
+t/mysql2............ok
+All tests successful, 1 test skipped.
+Files=17,  Tests=732, 40 wallclock secs (15.38 cusr +  1.30 csys = 16.68 CPU)
+[root@fenchurch Msql-Mysql-modules-1.2215]# make install
+
+These files are installed.
+/usr/bin/dbimon
+/usr/lib/perl5/man/man3/Bundle::DBD::mysql.3
+/usr/lib/perl5/man/man3/DBD::mysql.3
+/usr/lib/perl5/man/man3/Mysql.3
+/usr/lib/perl5/site_perl/5.005/i386-linux/Bundle/DBD/mysql.pm
+/usr/lib/perl5/site_perl/5.005/i386-linux/DBD/mysql.pm
+/usr/lib/perl5/site_perl/5.005/i386-linux/Mysql.pm
+/usr/lib/perl5/site_perl/5.005/i386-linux/Mysql/Statement.pm
+/usr/lib/perl5/site_perl/5.005/i386-linux/auto/DBD/mysql/mysql.bs
+/usr/lib/perl5/site_perl/5.005/i386-linux/auto/DBD/mysql/mysql.so
+/usr/man/man1/dbimon.1
+/usr/lib/perl5/site_perl/5.005/i386-linux/auto/Msql-Mysql-modules/.packlist
+
+

+

+This is how I installed the DBI perl modules. +

$dbh
+[root@fenchurch DBI-1.14]# perl Makefile.PL
+*** Note:
+    The optional PlRPC-modules (RPC::PlServer etc) are not installed.
+    If you want to use the DBD::Proxy driver and DBI::ProxyServer
+    modules, then you'll need to install the RPC::PlServer, RPC::PlClient,
+    Storable and Net::Daemon modules. The CPAN Bundle::DBI may help you.
+    You can install them any time after installing the DBI.
+    You do *not* need these modules for typical DBI usage.
+
+Optional modules are available from any CPAN mirror, in particular
+    http://www.perl.com/CPAN/modules/by-module
+    http://www.perl.org/CPAN/modules/by-module
+    ftp://ftp.funet.fi/pub/languages/perl/CPAN/modules/by-module
+
+Checking if your kit is complete...
+Looks good
+Writing Makefile for DBI
+
+    Remember to actually *read* the README file!
+    Use  'make' to build the software (dmake or nmake on Windows).
+    Then 'make test' to execute self tests.
+    Then 'make install' to install the DBI and then delete this working
+    directory before unpacking and building any DBD::* drivers.
+
+[root@fenchurch DBI-1.14]# make
+[root@fenchurch DBI-1.14]# make test
+PERL_DL_NONLAZY=1 /usr/bin/perl -Iblib/arch -Iblib/lib -I/usr/lib/perl5/5.00503/i386-linux -I/usr/lib/perl5/5.00503 -e 'use Test::Harness qw(&runtests $verbose); $verbose=0; runtests @ARGV;' t/*.t
+t/basics............ok
+t/dbidrv............ok
+t/examp.............ok
+t/meta..............ok
+t/proxy.............skipping test on this platform
+t/shell.............ok
+t/subclass..........ok
+All tests successful, 1 test skipped.
+Files=7,  Tests=179,  7 wallclock secs ( 6.46 cusr +  0.49 csys =  6.95 CPU)
+PERL_DL_NONLAZY=1 /usr/bin/perl -Iblib/arch -Iblib/lib -I/usr/lib/perl5/5.00503/i386-linux -I/usr/lib/perl5/5.00503 test.pl
+test.pl 
+DBI test application $Revision: 1.15 $
+Using /home/user/DBI-1.14/blib
+Switch: DBI 1.14 by Tim Bunce, 1.14
+Available Drivers: ADO, ExampleP, Multiplex, Proxy, mysql
+dbi:ExampleP:: testing 5 sets of 20 connections:
+Connecting... 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 
+Disconnecting...
+Connecting... 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 
+Disconnecting...
+Connecting... 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 
+Disconnecting...
+Connecting... 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 
+Disconnecting...
+Connecting... 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 
+Disconnecting...
+Made 100 connections in  0 wallclock secs ( 0.22 usr +  0.03 sys =  0.25 CPU)
+
+Testing handle creation speed...
+5000 NullP statement handles cycled in 6.6 cpu+sys seconds (762 per sec)
+
+test.pl done
+
+[root@fenchurch DBI-1.14]# make install
+These files are installed.
+/usr/lib/perl5/site_perl/5.005/i386-linux/auto/DBI/.packlist
+/usr/bin/dbiproxy
+/usr/bin/dbish
+/usr/lib/perl5/man/man3/Bundle::DBI.3
+/usr/lib/perl5/man/man3/DBD::ADO.3
+/usr/lib/perl5/man/man3/DBD::Multiplex.3
+/usr/lib/perl5/man/man3/DBD::Proxy.3
+/usr/lib/perl5/man/man3/DBI.3
+/usr/lib/perl5/man/man3/DBI::DBD.3
+/usr/lib/perl5/man/man3/DBI::FAQ.3
+/usr/lib/perl5/man/man3/DBI::Format.3
+/usr/lib/perl5/man/man3/DBI::ProxyServer.3
+/usr/lib/perl5/man/man3/DBI::Shell.3
+/usr/lib/perl5/man/man3/DBI::W32ODBC.3
+/usr/lib/perl5/man/man3/Win32::DBIODBC.3
+/usr/lib/perl5/site_perl/5.005/i386-linux/Bundle/DBI.pm
+/usr/lib/perl5/site_perl/5.005/i386-linux/DBD/ADO.pm
+/usr/lib/perl5/site_perl/5.005/i386-linux/DBD/ExampleP.pm
+/usr/lib/perl5/site_perl/5.005/i386-linux/DBD/Multiplex.pm
+/usr/lib/perl5/site_perl/5.005/i386-linux/DBD/NullP.pm
+/usr/lib/perl5/site_perl/5.005/i386-linux/DBD/Proxy.pm
+/usr/lib/perl5/site_perl/5.005/i386-linux/DBD/Sponge.pm
+/usr/lib/perl5/site_perl/5.005/i386-linux/DBI.pm
+/usr/lib/perl5/site_perl/5.005/i386-linux/DBI/DBD.pm
+/usr/lib/perl5/site_perl/5.005/i386-linux/DBI/FAQ.pm
+/usr/lib/perl5/site_perl/5.005/i386-linux/DBI/Format.pm
+/usr/lib/perl5/site_perl/5.005/i386-linux/DBI/ProxyServer.pm
+/usr/lib/perl5/site_perl/5.005/i386-linux/DBI/Shell.pm
+/usr/lib/perl5/site_perl/5.005/i386-linux/DBI/W32ODBC.pm
+/usr/lib/perl5/site_perl/5.005/i386-linux/Win32/DBIODBC.pm
+/usr/lib/perl5/site_perl/5.005/i386-linux/auto/DBI/DBI.bs
+/usr/lib/perl5/site_perl/5.005/i386-linux/auto/DBI/DBI.so
+/usr/lib/perl5/site_perl/5.005/i386-linux/auto/DBI/DBIXS.h
+/usr/lib/perl5/site_perl/5.005/i386-linux/auto/DBI/Driver.xst
+/usr/lib/perl5/site_perl/5.005/i386-linux/auto/DBI/dbd_xsh.h
+/usr/lib/perl5/site_perl/5.005/i386-linux/auto/DBI/dbi_sql.h
+/usr/lib/perl5/site_perl/5.005/i386-linux/auto/DBI/dbipport.h
+/usr/man/man1/dbiproxy.1
+/usr/man/man1/dbish.1
+
+

+ old notes in green

The following set of tarballs was found to work together properly on a LON-CAPA RedHat 6.2 system: @@ -174,13 +523,14 @@ 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 +565,9 @@ 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

+The Perl API

-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

-

-

-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 +630,43 @@ 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!"
+An up-to-date lond and lonsql.
+
+

+

Testing

+

+To test the backend MySQL database, a number of commands should be +run after installation. +

+

+These are sections of perl code which helps test the LON-CAPA network. +

+** 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 $pid;
@@ -536,14 +758,19 @@ sub make_new_child {
         exit;
     }
 }
-
-** LOND enabling of MySQL requestsw
-
-  This code is part of every lond child process in the way that it parses command request syntax
-  sent to it from lonc processes.  querysend corresponds to B-lonc sending the result of the query.
-  queryreply corresponds to B-lond indicating that it has received the request and will start the
-  database transaction (it returns "ok" to A-lonc ($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 +790,8 @@ 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);
 
+