File:  [LON-CAPA] / doc / build / Attic / loncapasqldatabase.html
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Fri Mar 1 22:14:00 2002 UTC (22 years, 3 months ago) by harris41
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CVS tags: version_0_5_1, version_0_5, version_0_4, stable_2002_july, stable_2002_april, STABLE, HEAD
removing loncapaconfig

    1: <HTML>
    2: <HEAD>
    3: <TITLE>LON-CAPA SQL Database Documentation</TITLE>
    4: </HEAD>
    5: <BODY>
    6: <H1>LON-CAPA SQL Database Documentation</H1>
    7: <P>
    8: Scott Harrison
    9: </P>
   10: <P>
   11: Last updated: 02/15/2001
   12: </P>
   13: <P>
   14: This file describes issues associated with LON-CAPA
   15: and a SQL database.
   16: </P>
   17: <H2>Latest HOWTO</H2>
   18: <P>
   19: <UL>
   20: <LI>Important notes
   21: <LI>Current status of documentation</LI>
   22: <LI>Current status of implementation</LI>
   23: <LI>Purpose within LON-CAPA</LI>
   24: <LI>Dependencies</LI>
   25: <LI>Installation</LI>
   26: <LI>Installation from source</LI>
   27: <LI>Configuration (automated)</LI>
   28: <LI>Manual configuration</LI>
   29: <LI>Testing</LI>
   30: <LI>Example sections of code relevant to LON-CAPA</LI>
   31: </UL>
   32: </P>
   33: <H2>Important notes</H2>
   34: <P>
   35: The current database is implemented assuming a non-adjustable
   36: architecture involving these data fields (specific to each version
   37: of a resource).
   38: <UL>
   39: <LI>title</LI>
   40: <LI>author</LI>
   41: <LI>subject</LI>
   42: <LI>notes</LI>
   43: <LI>abstract</LI>
   44: <LI>mime</LI>
   45: <LI>language</LI>
   46: <LI>creationdate</LI>
   47: <LI>lastrevisiondate</LI>
   48: <LI>owner</LI>
   49: <LI>copyright</LI>
   50: </UL>
   51: </P>
   52: <P>
   53: Security occurs as a function of the user 'www',
   54: and the permissions on the files in the /usr/local/mysql
   55: directory.  (These files and directories should
   56: be 700, 600, 500, 400, etc; not allow access to anyone
   57: but user 'www'.)
   58: </P>
   59: <P>
   60: These commands create the loncapameta database.
   61: <PRE>
   62: mysql> CREATE DATABASE IF NOT EXISTS loncapa;
   63: mysql> USE loncapa;
   64: mysql> CREATE TABLE IF NOT EXISTS metadata (title TEXT, author TEXT, subject TEXT, url TEXT, keywords TEXT, version TEXT, notes TEXT, abstract TEXT, mime TEXT, language TEXT, creationdate DATETIME, lastrevisiondate DATETIME, owner TEXT, copyright TEXT, FULLTEXT idx_title (title), FULLTEXT idx_author (author), FULLTEXT idx_subject (subject), FULLTEXT idx_url (url), FULLTEXT idx_keywords (keywords), FULLTEXT idx_version (version), FULLTEXT idx_notes (notes), FULLTEXT idx_abstract (abstract), FULLTEXT idx_mime (mime), FULLTEXT idx_language (language), FULLTEXT idx_owner (owner), FULLTEXT idx_copyright (copyright)) TYPE=MYISAM;
   65: mysql> INSERT INTO metadata VALUES ('The Structure of Scientific Revolutions','Thomas S. Kuhn','scientific philosophy','/res/msu/shh1/poobah2.html','aphorisms, theories, paradigm, revolution','current','still developing','This famous book stands out in contrast to the more rigid theories of Popper.','html','seniso','1999-03-03 12:34:56','1999-03-03 3:12:00','shh1@msu.edu','default');
   66: mysql> SELECT * FROM metadata WHERE title REGEXP "1";
   67: </PRE>
   68: </P>
   69: <P>
   70: Current time values for things.
   71: <PRE>
   72: fenchurch.lite.msu.edu
   73: Mem:    46812K av,   45632K used,    1180K free,   14756K shrd,    4292K buff
   74: Swap: 1148608K av,   11260K used, 1137348K free                   13244K cached
   75: 
   76: Red Hat Linux release 6.2 (Zoot)
   77: Kernel 2.2.16-3 on an i586
   78: </PRE>
   79: <BR>Q: How big are data records in test database? A: on average, 1000 bytes each, medline records from PubMed.
   80: <BR>Q: How big is the biggest field? A: on average, 838 bytes each
   81: <BR>Q: How much time to insert 5284 medline records into database?
   82: A: 600 seconds
   83: <BR>Q: What about when using "speed-technique" on page 130? A: 689 seconds (weird, eh?)
   84: <BR>Q: What about REGEXP searching? A: about 1-2 seconds for small fields;
   85: 10 to 20 seconds for REGEXP search on "abstract" field
   86: <BR>Q: What about FULLTEXT indexing? A: about 6 seconds for abstract field.
   87: 
   88: </P>
   89: <P>
   90: An important quote from the manual:
   91: <BLOCKQUOTE>
   92: 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
   93: 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. 
   94: </BLOCKQUOTE>
   95: </P>
   96: <P>
   97: I plan on using a MyISAM table type with 11 metadata fields of column 
   98: type=TEXT.
   99: </P>
  100: <P>
  101: It might be worthwhile to look at /usr/local/mysql/manual.html.
  102: It is quite in depth.
  103: </P>
  104: <H2>Current status of documentation</H2>
  105: <P>
  106: I am going to begin documentation by inserting what notes
  107: I have into this file.  I will be subsequently rearranging
  108: them and editing them based on the tests that I conduct.
  109: I am trying to make sure that documentation, installation,
  110: and run-time issues are all consistent and correct.  The
  111: current status of everything is that it works and has
  112: been minimally tested, but things need to be cleaned up
  113: and checked again!
  114: </P>
  115: <H2>Current status of implementation</H2>
  116: <P>
  117: Need to
  118: <UL>
  119: <LI>Installation: Fix binary file listings for user permissions and ownership.
  120: <LI>Installation: Make sure sql server starts, and if database does not
  121: exist, then create. (/etc/rc.d).
  122: <LI>Processes: Make sure loncron initiates lonsql on library machines.
  123: <LI>Read in metadata from right place periodically.
  124: <LI>Implement tested perl module handler.
  125: </UL>
  126: <P>
  127: Right now, a lot of "feasibility" work has been done.
  128: Recipes for manual installation and configuration have
  129: been gathered.  Network connectivity of lond->lonsql->lond->lonc
  130: type tests have been performed.  A binary installation
  131: has been compiled in an RPM (LON-CAPA-mysql, with perl components
  132: a part of LON-CAPA-systemperl).
  133: The most lacking test in terms of feasibility has
  134: been looking at benchmarks to analyze the load at which
  135: the SQL database can efficiently allow many users to
  136: make simultaneous requests of the metadata database.
  137: </P>
  138: <P>
  139: Documentation has been pieced together over time.  But,
  140: as mentioned in the previous section, it needs an
  141: overhaul.
  142: </P>
  143: <P>
  144: The binary installation has some quirks associated with it.
  145: Some of the user permissions are wrong, although this is
  146: benign.  Also, other options of binary installation (such
  147: as using binary RPMs put together by others) were dismissed
  148: given the difficulty of getting differing combinations of
  149: these external RPMs to work together.
  150: </P>
  151: <P>
  152: Most configuration questions have been initially worked out
  153: to the point of getting this SQL software component working,
  154: however there may be more optimal approaches than currently
  155: exist.
  156: </P>
  157: <H2>Purpose within LON-CAPA</H2>
  158: <P>
  159: LON-CAPA is meant to distribute A LOT of educational content
  160: to A LOT of people.  It is ineffective to directly rely on contents
  161: within the ext2 filesystem to be speedily scanned for 
  162: on-the-fly searches of content descriptions.  (Simply put,
  163: it takes a cumbersome amount of time to open, read, analyze, and
  164: close thousands of files.)
  165: </P>
  166: <P>
  167: The solution is to hash-index various data fields that are
  168: descriptive of the educational resources on a LON-CAPA server
  169: machine.  Descriptive data fields are referred to as
  170: "metadata".  The question then arises as to how this metadata
  171: is handled in terms of the rest of the LON-CAPA network
  172: without burdening client and daemon processes.  I now
  173: answer this question in the format of Problem and Solution
  174: below.
  175: </P>
  176: <P>
  177: <PRE>
  178: PROBLEM SITUATION:
  179: 
  180:   If Server A wants data from Server B, Server A uses a lonc process to
  181:   send a database command to a Server B lond process.
  182:     lonc= loncapa client process    A-lonc= a lonc process on Server A
  183:     lond= loncapa daemon process
  184: 
  185:                  database command
  186:     A-lonc  --------TCP/IP----------------> B-lond
  187: 
  188:   The problem emerges that A-lonc and B-lond are kept waiting for the
  189:   MySQL server to "do its stuff", or in other words, perform the conceivably
  190:   sophisticated, data-intensive, time-sucking database transaction.  By tying
  191:   up a lonc and lond process, this significantly cripples the capabilities
  192:   of LON-CAPA servers. 
  193: 
  194:   While commercial databases have a variety of features that ATTEMPT to
  195:   deal with this, freeware databases are still experimenting and exploring
  196:   with different schemes with varying degrees of performance stability.
  197: 
  198: THE SOLUTION:
  199: 
  200:   A separate daemon process was created that B-lond works with to
  201:   handle database requests.  This daemon process is called "lonsql".
  202: 
  203:   So,
  204:                 database command
  205:   A-lonc  ---------TCP/IP-----------------> B-lond =====> B-lonsql
  206:          <---------------------------------/                |
  207:            "ok, I'll get back to you..."                    |
  208:                                                             |
  209:                                                             /
  210:   A-lond  <-------------------------------  B-lonc   <======
  211:            "Guess what? I have the result!"
  212: 
  213:   Of course, depending on success or failure, the messages may vary,
  214:   but the principle remains the same where a separate pool of children
  215:   processes (lonsql's) handle the MySQL database manipulations.
  216: </PRE>
  217: </P>
  218: <H2>Dependencies</H2>
  219: <P>
  220: I believe (but am not 100% confident) that the following
  221: RPMs are necessary (in addition to the current ones
  222: in rpm_list.txt) to run MySQL.  Basically I discovered these
  223: dependencies while trying to do external RPM based installs.
  224: I assume, and sometimes found, that these dependencies apply
  225: to tarball-based distributions too.  (So to play it on the
  226: safe side, I am going to include these RPMs as part of the
  227: core, minimal RPM set.)
  228: <UL>
  229: <LI>egcs-1.1.2-30</LI>
  230: <LI>cpp-1.1.2-30</LI>
  231: <LI>glibc-devel-2.1.3-15</LI>
  232: <LI>zlib-devel-1.1.3-6</LI>
  233: </UL>
  234: </P>
  235: <H2>Installation</H2>
  236: <P>
  237: Installation of the LON-CAPA SQL database normally occurs
  238: by default when using the LON-CAPA installation CD
  239: (see http://install.lon-capa.org).  It is installed
  240: as the LON-CAPA-mysql RPM.  This RPM encodes for the MySQL
  241: engine.  Related perl interfaces (Perl::DBI, Perl::Msql-Mysql)
  242: are encoded in the LON-CAPA-systemperl RPM.
  243: </P>
  244: <P>
  245: The three components of a MySQL installation for the
  246: LON-CAPA system are further described immediately below.
  247: <TABLE BORDER="0">
  248: <TR><TD COLSPAN="2"><STRONG>Perl::DBI module</STRONG>-
  249: the API "front-end"...</TD></TR>
  250: <TR><TD WIDTH="10%"></TD><TD>database interface module for organizing generic
  251: database commands which are independent of specific
  252: database implementation (such as MySQL, mSQL, Postgres, etc).
  253: </TD></TR>
  254: <TR><TD COLSPAN="2"><STRONG>Perl::MySQL module</STRONG>-
  255: the API "mid-section"...</TD></TR>
  256: <TR><TD WIDTH="10%"></TD><TD>the module to directly interface with the actual
  257: MySQL database engine</TD></TR>
  258: <TR><TD COLSPAN="2"><STRONG>MySQL database engine</STRONG>-
  259: the "back-end"...</TD></TR>
  260: <TR><TD WIDTH="10%"></TD><TD>the binary installation (compiled either
  261: from source or pre-compiled file listings) which provides the
  262: actual MySQL functionality on the system</TD></TR>
  263: </TABLE>
  264: </P>
  265: <H2>Installation from source</H2>
  266: <P>
  267: Note: the mysql site recommends that Linux users install by
  268: using the MySQL RPMs (MySQL-client, MySQL, MySQL-shared, etc).
  269: While these RPMs work, I was unsuccessful at integrating
  270: this RPM-installed database with perl modules from www.cpan.org.
  271: Hence, I <STRONG>strongly</STRONG> recommend that, when installing
  272: from "source", MySQL and the perl components be in fact installed
  273: from their tarballs (.tar.gz, .tgz).  (Perl components, when installed
  274: from RPMs, also wound up in incorrect locations on the disk.)
  275: Do not coordinate a source install with externally made RPMs!
  276: It is, of course, okay to use LON-CAPA RPMs such as LON-CAPA-systemperl
  277: and LON-CAPA-mysql since we, in fact, made these RPMs correctly :).
  278: <UL>
  279: <LI>http://www.cpan.org/authors/id/JWIED/Msql-Mysql-modules-1.2215.tar.gz
  280: <BR>This tarball Released 20th August 2000
  281: <LI>http://www.mysql.com/Downloads/MySQL-3.23/mysql-3.23.33-pc-linux-gnu-i686.tar.gz
  282: <BR>This tarball Last changed 2000-11-11
  283: <BR>This is actually a binary tarball (as opposed to source code
  284: that is subsequently compiled).
  285: <LI>http://www.cpan.org/authors/id/TIMB/DBI-1.14.tar.gz
  286: <BR>This tarball Released 14th June 2000
  287: </UL>
  288: </P>
  289: <P>So, here is exactly how I installed MySQL-3.23. (Note that all files
  290: wind up in /usr/local/mysql-3.23.33-pc-linux-gnu-i686 except for
  291: a link from /usr/local/mysql to /usr/local/mysql-3.23.33-pc-linux-gnu-i686
  292: and some files involved in system process handling (/etc/rc.d/*/*mysql).
  293: <PRE>
  294: (As user=root)
  295: cd /usr/local/;
  296: tar xzvf mysql-3.23.33-pc-linux-gnu-i686.tar.gz
  297: ln -s /usr/local/mysql-3.23.33-pc-linux-gnu-i686 mysql
  298: cd /usr/local/mysql
  299: chown -R www /usr/local/mysql/.
  300: chgrp -R users /usr/local/mysql/.
  301: chmod -R g-w,g-r,g-x /usr/local/mysql/.
  302: (probably also want chmod -R a-w,a-r,a-x /usr/local/mysql/.)
  303: 
  304: Alter <TT>safe_mysqld</TT>
  305: and <TT>support-files/mysql.server</TT> to use 'localhosts' instead
  306: of `bin/hostname`.  Also, to use user 'www' instead of 'mysql'.
  307: 
  308: (These changes could be done with /etc/my.cnf, but
  309: I think this approach makes sure the database NEVER
  310: gets screwed up due to somebody forgetting to install /etc/my.cnf).
  311: 
  312: Change this line in mysql.server from
  313:   pid_file=$datadir/`@HOSTNAME@`.pid
  314: to
  315:   pid_file=$datadir/localhost.pid
  316: 
  317: Change this line in safe_mysqld from
  318: user=root
  319: to
  320: user=www
  321: 
  322: Change this line in safe_mysqld from
  323:   pid_file=$DATADIR/`/bin/hostname`.pid
  324: to
  325:   pid_file=$DATADIR/localhost.pid
  326: 
  327: Change this line in safe_mysqld from
  328: test -z "$err_log"  && err_log=$DATADIR/`/bin/hostname`.err
  329: to
  330: test -z "$err_log"  && err_log=$DATADIR/localhost.err
  331: 
  332: cp -p support-files/mysql.server /etc/rc.d/init.d/mysql
  333: chmod 755 /etc/rc.d/init.d/mysql
  334: /sbin/chkconfig --add mysql
  335: /etc/rc.d/init.d/mysql start
  336: 
  337: </PRE>
  338: </P>
  339: <P>This is how I installed the Msql-Mysql-modules perl modules.
  340: <PRE>
  341: [root@fenchurch Msql-Mysql-modules-1.2215]# perl Makefile.PL 
  342: Which drivers do you want to install?
  343: 
  344:     1)	MySQL only
  345:     2)	mSQL only (either of mSQL 1 or mSQL 2)
  346:     3)  MySQL and mSQL (either of mSQL 1 or mSQL 2)
  347: 
  348:     4)  mSQL 1 and mSQL 2
  349:     5)  MySQL, mSQL 1 and mSQL 2
  350: 
  351: Enter the appropriate number:  [3] 1
  352: 
  353: 
  354: Do you want to install the MysqlPerl emulation? You might keep your old
  355: Mysql module (to be distinguished from DBD::mysql!) if you are concerned
  356: about compatibility to existing applications! [y] n
  357: Where is your MySQL installed? Please tell me the directory that
  358: contains the subdir 'include'. [/usr/local/mysql] 
  359: Which database should I use for testing the MySQL drivers? [test] 
  360: On which host is database test running (hostname, ip address
  361: or host:port) [localhost] 
  362: User name for connecting to database test? [undef]
  363: Password for connecting to database test? [undef]
  364: [root@fenchurch Msql-Mysql-modules-1.2215]# make
  365: [root@fenchurch Msql-Mysql-modules-1.2215]# make test
  366: make[1]: Entering directory `/home/user/Msql-Mysql-modules-1.2215/mysql'
  367: make[1]: Leaving directory `/home/user/Msql-Mysql-modules-1.2215/mysql'
  368: make[1]: Entering directory `/home/user/Msql-Mysql-modules-1.2215/mysql'
  369: 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); $verbose=0; runtests @ARGV;' t/*.t
  370: t/00base............ok
  371: t/10dsnlist.........ok
  372: t/20createdrop......ok
  373: t/30insertfetch.....ok
  374: t/40bindparam.......ok
  375: t/40blobs...........ok
  376: t/40listfields......ok
  377: t/40nulls...........ok
  378: t/40numrows.........ok
  379: t/50chopblanks......ok
  380: t/50commit..........ok
  381: t/60leaks...........skipping test on this platform
  382: t/ak-dbd............ok
  383: t/akmisc............ok
  384: t/dbdadmin..........ok
  385: t/mysql.............ok
  386: t/mysql2............ok
  387: All tests successful, 1 test skipped.
  388: Files=17,  Tests=732, 40 wallclock secs (15.38 cusr +  1.30 csys = 16.68 CPU)
  389: [root@fenchurch Msql-Mysql-modules-1.2215]# make install
  390: 
  391: These files are installed.
  392: /usr/bin/dbimon
  393: /usr/lib/perl5/man/man3/Bundle::DBD::mysql.3
  394: /usr/lib/perl5/man/man3/DBD::mysql.3
  395: /usr/lib/perl5/man/man3/Mysql.3
  396: /usr/lib/perl5/site_perl/5.005/i386-linux/Bundle/DBD/mysql.pm
  397: /usr/lib/perl5/site_perl/5.005/i386-linux/DBD/mysql.pm
  398: /usr/lib/perl5/site_perl/5.005/i386-linux/Mysql.pm
  399: /usr/lib/perl5/site_perl/5.005/i386-linux/Mysql/Statement.pm
  400: /usr/lib/perl5/site_perl/5.005/i386-linux/auto/DBD/mysql/mysql.bs
  401: /usr/lib/perl5/site_perl/5.005/i386-linux/auto/DBD/mysql/mysql.so
  402: /usr/man/man1/dbimon.1
  403: /usr/lib/perl5/site_perl/5.005/i386-linux/auto/Msql-Mysql-modules/.packlist
  404: </PRE>
  405: </P>
  406: <P>
  407: This is how I installed the DBI perl modules.
  408: <PRE>$dbh
  409: [root@fenchurch DBI-1.14]# perl Makefile.PL
  410: *** Note:
  411:     The optional PlRPC-modules (RPC::PlServer etc) are not installed.
  412:     If you want to use the DBD::Proxy driver and DBI::ProxyServer
  413:     modules, then you'll need to install the RPC::PlServer, RPC::PlClient,
  414:     Storable and Net::Daemon modules. The CPAN Bundle::DBI may help you.
  415:     You can install them any time after installing the DBI.
  416:     You do *not* need these modules for typical DBI usage.
  417: 
  418: Optional modules are available from any CPAN mirror, in particular
  419:     http://www.perl.com/CPAN/modules/by-module
  420:     http://www.perl.org/CPAN/modules/by-module
  421:     ftp://ftp.funet.fi/pub/languages/perl/CPAN/modules/by-module
  422: 
  423: Checking if your kit is complete...
  424: Looks good
  425: Writing Makefile for DBI
  426: 
  427:     Remember to actually *read* the README file!
  428:     Use  'make' to build the software (dmake or nmake on Windows).
  429:     Then 'make test' to execute self tests.
  430:     Then 'make install' to install the DBI and then delete this working
  431:     directory before unpacking and building any DBD::* drivers.
  432: 
  433: [root@fenchurch DBI-1.14]# make
  434: [root@fenchurch DBI-1.14]# make test
  435: 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
  436: t/basics............ok
  437: t/dbidrv............ok
  438: t/examp.............ok
  439: t/meta..............ok
  440: t/proxy.............skipping test on this platform
  441: t/shell.............ok
  442: t/subclass..........ok
  443: All tests successful, 1 test skipped.
  444: Files=7,  Tests=179,  7 wallclock secs ( 6.46 cusr +  0.49 csys =  6.95 CPU)
  445: 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
  446: test.pl 
  447: DBI test application $Revision: 1.17 $
  448: Using /home/user/DBI-1.14/blib
  449: Switch: DBI 1.14 by Tim Bunce, 1.14
  450: Available Drivers: ADO, ExampleP, Multiplex, Proxy, mysql
  451: dbi:ExampleP:: testing 5 sets of 20 connections:
  452: Connecting... 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 
  453: Disconnecting...
  454: Connecting... 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 
  455: Disconnecting...
  456: Connecting... 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 
  457: Disconnecting...
  458: Connecting... 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 
  459: Disconnecting...
  460: Connecting... 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 
  461: Disconnecting...
  462: Made 100 connections in  0 wallclock secs ( 0.22 usr +  0.03 sys =  0.25 CPU)
  463: 
  464: Testing handle creation speed...
  465: 5000 NullP statement handles cycled in 6.6 cpu+sys seconds (762 per sec)
  466: 
  467: test.pl done
  468: 
  469: [root@fenchurch DBI-1.14]# make install
  470: These files are installed.
  471: /usr/lib/perl5/site_perl/5.005/i386-linux/auto/DBI/.packlist
  472: /usr/bin/dbiproxy
  473: /usr/bin/dbish
  474: /usr/lib/perl5/man/man3/Bundle::DBI.3
  475: /usr/lib/perl5/man/man3/DBD::ADO.3
  476: /usr/lib/perl5/man/man3/DBD::Multiplex.3
  477: /usr/lib/perl5/man/man3/DBD::Proxy.3
  478: /usr/lib/perl5/man/man3/DBI.3
  479: /usr/lib/perl5/man/man3/DBI::DBD.3
  480: /usr/lib/perl5/man/man3/DBI::FAQ.3
  481: /usr/lib/perl5/man/man3/DBI::Format.3
  482: /usr/lib/perl5/man/man3/DBI::ProxyServer.3
  483: /usr/lib/perl5/man/man3/DBI::Shell.3
  484: /usr/lib/perl5/man/man3/DBI::W32ODBC.3
  485: /usr/lib/perl5/man/man3/Win32::DBIODBC.3
  486: /usr/lib/perl5/site_perl/5.005/i386-linux/Bundle/DBI.pm
  487: /usr/lib/perl5/site_perl/5.005/i386-linux/DBD/ADO.pm
  488: /usr/lib/perl5/site_perl/5.005/i386-linux/DBD/ExampleP.pm
  489: /usr/lib/perl5/site_perl/5.005/i386-linux/DBD/Multiplex.pm
  490: /usr/lib/perl5/site_perl/5.005/i386-linux/DBD/NullP.pm
  491: /usr/lib/perl5/site_perl/5.005/i386-linux/DBD/Proxy.pm
  492: /usr/lib/perl5/site_perl/5.005/i386-linux/DBD/Sponge.pm
  493: /usr/lib/perl5/site_perl/5.005/i386-linux/DBI.pm
  494: /usr/lib/perl5/site_perl/5.005/i386-linux/DBI/DBD.pm
  495: /usr/lib/perl5/site_perl/5.005/i386-linux/DBI/FAQ.pm
  496: /usr/lib/perl5/site_perl/5.005/i386-linux/DBI/Format.pm
  497: /usr/lib/perl5/site_perl/5.005/i386-linux/DBI/ProxyServer.pm
  498: /usr/lib/perl5/site_perl/5.005/i386-linux/DBI/Shell.pm
  499: /usr/lib/perl5/site_perl/5.005/i386-linux/DBI/W32ODBC.pm
  500: /usr/lib/perl5/site_perl/5.005/i386-linux/Win32/DBIODBC.pm
  501: /usr/lib/perl5/site_perl/5.005/i386-linux/auto/DBI/DBI.bs
  502: /usr/lib/perl5/site_perl/5.005/i386-linux/auto/DBI/DBI.so
  503: /usr/lib/perl5/site_perl/5.005/i386-linux/auto/DBI/DBIXS.h
  504: /usr/lib/perl5/site_perl/5.005/i386-linux/auto/DBI/Driver.xst
  505: /usr/lib/perl5/site_perl/5.005/i386-linux/auto/DBI/dbd_xsh.h
  506: /usr/lib/perl5/site_perl/5.005/i386-linux/auto/DBI/dbi_sql.h
  507: /usr/lib/perl5/site_perl/5.005/i386-linux/auto/DBI/dbipport.h
  508: /usr/man/man1/dbiproxy.1
  509: /usr/man/man1/dbish.1
  510: </PRE>
  511: </P>
  512: <FONT COLOR="green"> old notes in green
  513: <P>
  514: The following set of tarballs was found to work together
  515: properly on a LON-CAPA RedHat 6.2 system:
  516: <UL>
  517: <LI>DBI-1.13.tar.gz
  518: <LI>Msql-Mysql-modules-1.2209.tar.gz
  519: <LI>mysql-3.22.32.tar.gz
  520: </UL>
  521: </P>
  522: <P>
  523: Installation was simply a matter of following the instructions
  524: and typing the several "make" commands for each 
  525: </P>
  526: </FONT>
  527: <H2>Configuration (automated)</H2>
  528: <P>
  529: Not yet stabilized.  We are looking at webmin
  530: and/or a text-UI tool with less software dependencies
  531: than the python-anaconda hunk represented by
  532: the prior loncapaconfig.
  533: </P>
  534: <H2>Manual configuration</H2>
  535: <P>
  536: This is not complete.
  537: </P>
  538: <P>
  539: <STRONG>Starting the mysql daemon</STRONG>: Login on the Linux
  540: system as user 'www'.  Enter the command
  541: <TT>/usr/local/bin/safe_mysqld &</TT>
  542: </P>
  543: <P>
  544: <STRONG>Set a password for 'root'</STRONG>:
  545: <TT>/usr/local/bin/mysqladmin -u root password 'new-password'</TT>
  546: </P>
  547: <P>
  548: <STRONG>Adding a user</STRONG>:  Start the mysql daemon.  Login to the
  549: mysql system as root (<TT>mysql -u root -p mysql</TT>)
  550: and enter the right password (for instance 'newmysql').  Add the user
  551: www
  552: <PRE>
  553: INSERT INTO user (Host, User, Password)
  554: VALUES ('localhost','www',password('newmysql'));
  555: </PRE>
  556: </P>
  557: <P>
  558: <STRONG>Granting privileges to user 'www'</STRONG>:
  559: <PRE>
  560: GRANT ALL PRIVILEGES ON *.* TO www@localhost;
  561: FLUSH PRIVILEGES;
  562: </PRE>
  563: </P>
  564: <P>
  565: <STRONG>Set the SQL server to start upon system startup</STRONG>:
  566: Copy support-files/mysql.server to the right place on the system
  567: (/etc/rc.d/...).
  568: </P>
  569: <P>
  570: <STRONG>The Perl API</STRONG>
  571: <PRE>
  572:    $dbh = DBI->connect(	"DBI:mysql:loncapa",
  573: 			"www",
  574: 			"SOMEPASSWORD",
  575: 			{ RaiseError =>0,PrintError=>0});
  576: 
  577: There is an obvious need to CONNECT to the database, and in order to do
  578: this, there must be:
  579:   a RUNNING mysql daemon;
  580:   a DATABASE named "loncapa";
  581:   a USER named "www";
  582:   and an ABILITY for LON-CAPA on one machine to access
  583:        SQL database on another machine;
  584:   
  585: So, here are some notes on implementing these configurations.
  586: 
  587: ** RUNNING mysql daemon (safe_mysqld method)
  588: 
  589: The recommended way to run the MySQL daemon is as a non-root user
  590: (probably www)...
  591: 
  592: so, 1) login as user www on the linux machine
  593:     2) start the mysql daemon as /usr/local/bin/safe_mysqld &
  594: 
  595: safe_mysqld only works if the local installation of MySQL is set to the
  596: right directory permissions which I found to be:
  597: chown www:users /usr/local/var/mysql
  598: chown www:users /usr/local/lib/mysql
  599: chown -R www:users /usr/local/mysql
  600: chown www:users /usr/local/include/mysql
  601: chown www:users /usr/local/var
  602: 
  603: ** DATABASE named "loncapa"
  604: 
  605: As user www, run this command
  606:     mysql -u root -p mysql
  607: enter the password as SOMEPASSWORD
  608: 
  609: This allows you to manually enter MySQL commands.
  610: The MySQL command to generate the loncapa DATABASE is:
  611: 
  612: CREATE DATABASE 'loncapa';
  613: 
  614: ** USER named "www"
  615: 
  616: As user www, run this command
  617:     mysql -u root -p mysql
  618: enter the password as SOMEPASSWORD
  619: 
  620: To add the user www to the MySQL server, and grant all
  621: privileges on *.* to www@localhost identified by 'SOMEPASSWORD'
  622: with grant option;
  623: 
  624: INSERT INTO user (Host, User, Password)
  625: VALUES ('localhost','www',password('SOMEPASSWORD'));
  626: 
  627: GRANT ALL PRIVILEGES ON *.* TO www@localhost;
  628: 
  629: FLUSH PRIVILEGES;
  630: 
  631: ** ABILITY for LON-CAPA machines to communicate with SQL databases on
  632:    other LON-CAPA machines
  633: 
  634: An up-to-date lond and lonsql.
  635: </PRE>
  636: </P>
  637: <H2>Testing</H2>
  638: <P>
  639: To test the backend MySQL database, a number of commands should be
  640: run after installation.
  641: <UL>
  642: <LI><TT>cd /usr/local/mysql/sql-bench; ./run-all-tests --small-test</TT></LI>
  643: <BR>without the --small-test flag, this test can take more than 10 hours!
  644: <LI><TT>cd /usr/local/mysql; bin/mysqladmin version</TT></LI>
  645: <LI><TT>cd /usr/local/mysql; bin/mysqladmin variables</TT></LI>
  646: <LI><TT>cd /usr/local/mysql; bin/mysqlshow</TT></LI>
  647: <LI><TT>cd /usr/local/mysql; bin/mysqlshow mysql</TT></LI>
  648: <LI><TT>cd /usr/local/mysql; bin/mysql -e "select host,db,user from db" mysql</TT></LI>
  649: <LI><TT>cd /usr/local/mysql/mysql-test; ./test-run-all</TT></LI>
  650: 
  651: </UL>
  652: <P>
  653: These are sections of perl code which helps test the LON-CAPA network.
  654: <PRE>
  655: <STRONG>** TEST the database connection with my current tester.pl code
  656: which mimics what command will eventually be sent through lonc.</STRONG>
  657: 
  658: $reply=reply(
  659:     "querysend:SELECT * FROM general_information WHERE Id='AAAAA'",$lonID);
  660: </PRE>
  661: </P>
  662: <H2>Example sections of code relevant to LON-CAPA</H2>
  663: <P>
  664: Here are excerpts of code which implement the above handling:
  665: </P>
  666: <P>
  667: <PRE>
  668: <STRONG>**LONSQL
  669: A subroutine from "lonsql" which establishes a child process for handling
  670: database interactions.</STRONG>
  671: 
  672: sub make_new_child {
  673:     my $pid;
  674:     my $sigset;
  675:     
  676:     # block signal for fork
  677:     $sigset = POSIX::SigSet->new(SIGINT);
  678:     sigprocmask(SIG_BLOCK, $sigset)
  679:         or die "Can't block SIGINT for fork: $!\n";
  680:     
  681:     die "fork: $!" unless defined ($pid = fork);
  682:     
  683:     if ($pid) {
  684:         # Parent records the child's birth and returns.
  685:         sigprocmask(SIG_UNBLOCK, $sigset)
  686:             or die "Can't unblock SIGINT for fork: $!\n";
  687:         $children{$pid} = 1;
  688:         $children++;
  689:         return;
  690:     } else {
  691:         # Child can *not* return from this subroutine.
  692:         $SIG{INT} = 'DEFAULT';      # make SIGINT kill us as it did before
  693:     
  694:         # unblock signals
  695:         sigprocmask(SIG_UNBLOCK, $sigset)
  696:             or die "Can't unblock SIGINT for fork: $!\n";
  697: 	
  698: 	
  699:         #open database handle
  700: 	# making dbh global to avoid garbage collector
  701: 	unless (
  702: 		$dbh = DBI->connect("DBI:mysql:loncapa","www","SOMEPASSWORD",{ RaiseError =>0,PrintError=>0})
  703: 		) { 
  704: 	            my $st=120+int(rand(240));
  705: 		    &logthis("<font color=blue>WARNING: Couldn't connect to database  ($st secs): $@</font>");
  706: 		    print "database handle error\n";
  707: 		    sleep($st);
  708: 		    exit;
  709: 
  710: 	  };
  711: 	# make sure that a database disconnection occurs with ending kill signals
  712: 	$SIG{TERM}=$SIG{INT}=$SIG{QUIT}=$SIG{__DIE__}=\&DISCONNECT;
  713: 
  714:         # handle connections until we've reached $MAX_CLIENTS_PER_CHILD
  715:         for ($i=0; $i < $MAX_CLIENTS_PER_CHILD; $i++) {
  716:             $client = $server->accept()     or last;
  717:             
  718:             # do something with the connection
  719: 	    $run = $run+1;
  720: 	    my $userinput = <$client>;
  721: 	    chomp($userinput);
  722: 	    	    
  723: 	    my ($conserver,$querytmp)=split(/&/,$userinput);
  724: 	    my $query=unescape($querytmp);
  725: 
  726:             #send query id which is pid_unixdatetime_runningcounter
  727: 	    $queryid = $thisserver;
  728: 	    $queryid .="_".($$)."_";
  729: 	    $queryid .= time."_";
  730: 	    $queryid .= $run;
  731: 	    print $client "$queryid\n";
  732: 	    
  733:             #prepare and execute the query
  734: 	    my $sth = $dbh->prepare($query);
  735: 	    my $result;
  736: 	    unless ($sth->execute())
  737: 	    {
  738: 		&logthis("<font color=blue>WARNING: Could not retrieve from database: $@</font>");
  739: 		$result="";
  740: 	    }
  741: 	    else {
  742: 		my $r1=$sth->fetchall_arrayref;
  743: 		my @r2; map {my $a=$_; my @b=map {escape($_)} @$a; push @r2,join(",", @b)} (@$r1);
  744: 		$result=join("&",@r2) . "\n";
  745: 	    }
  746:             &reply("queryreply:$queryid:$result",$conserver);
  747: 
  748:         }
  749:     
  750:         # tidy up gracefully and finish
  751: 	
  752:         #close the database handle
  753: 	$dbh->disconnect
  754: 	   or &logthis("<font color=blue>WARNING: Couldn't disconnect from database  $DBI::errstr ($st secs): $@</font>");
  755:     
  756:         # this exit is VERY important, otherwise the child will become
  757:         # a producer of more and more children, forking yourself into
  758:         # process death.
  759:         exit;
  760:     }
  761: }
  762: </P>
  763: <P>
  764: <STRONG>** LOND enabling of MySQL requests</STRONG>
  765: <BR />
  766: This code is part of every lond child process in the
  767: way that it parses command request syntax sent to it
  768: from lonc processes.  Based on the diagram above, querysend
  769: corresponds to B-lonc sending the result of the query.
  770: queryreply corresponds to B-lond indicating that it has
  771: received the request and will start the database transaction
  772: (it returns "ok" to
  773: A-lonc ($client)).
  774: <PRE>
  775: # ------------------------------------------------------------------- querysend
  776:                    } elsif ($userinput =~ /^querysend/) {
  777:                        my ($cmd,$query)=split(/:/,$userinput);
  778: 		       $query=~s/\n*$//g;
  779:                      print $client sqlreply("$hostid{$clientip}\&$query")."\n";
  780: # ------------------------------------------------------------------ queryreply
  781:                    } elsif ($userinput =~ /^queryreply/) {
  782:                        my ($cmd,$id,$reply)=split(/:/,$userinput); 
  783: 		       my $store;
  784:                        my $execdir=$perlvar{'lonDaemons'};
  785:                        if ($store=IO::File->new(">$execdir/tmp/$id")) {
  786: 			   print $store $reply;
  787: 			   close $store;
  788: 			   print $client "ok\n";
  789: 		       }
  790: 		       else {
  791: 			   print $client "error:$!\n";
  792: 		       }
  793: 
  794: </PRE>
  795: 
  796: </P>
  797: </BODY>
  798: </HTML>

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