Manual:MWDumper

MWDumper is a tool written in Java for extracting sets of pages from a MediaWiki dump file. For example, it can load Wikipedia's content into MediaWiki.

MWDumper can read MediaWiki XML export dumps (version 0.3, minus uploads), perform optional filtering, and output back to XML or to SQL statements to add things directly to a database in 1.4 or 1.5 schema.

Beware that MWDumper has not been actively maintained since the mid-2000s, and may or may not work with current deployments. Some new maintenance is going on as of December 2015.

While this can be used to import XML dumps into a MediaWiki database, it might not be the best choice for small imports (say, 100 pages or less). See Manual:Importing XML dumps for an overview.

Where to find it
To import current XML export dumps, you'll need an up-to-date build of MWDumper...

Current WMF builds' are produced by jenkins. For the latest version check the jenkins build. You can find a mostly up-to-date build at https://integration.wikimedia.org/ci/view/Java/job/mwdumper-maven/. The version at dumps.wikimedia.org is from February 2013.

You can build an up to date MWDumper from. (See, below).

Potentially out of date builds:

Third-party builds (that start in GUI mode by default so you won't need most of the parameters below, but they may not contain the latest bug fixes) – just run it with )

There are also third party builds without the gui default.

Prerequisites for imports via MWDumper
Before using mwdumper, your page, text, and revision tables must be empty. To empty them, do this (note that this will wipe out an existing wiki): In SQL: DELETE FROM page; DELETE FROM text; DELETE FROM revision; In maintenance directory: php rebuildall.php

Import dump files with MWDumper
Sample command line for a direct database import: java -jar mwdumper.jar --format=sql:1.5 pages_full.xml.bz2 | mysql -u -p  to MySQL in the above sample command.

If you want to use the output of mwdumper in a JDBC URL, you should use set  in the query string.

Also make sure that your MediaWiki tables use CHARACTER SET=binary. Otherwise, you may get error messages like  because MySQL fails to distinguish certain characters.

Complex filtering
You can also do complex filtering to produce multiple output files: java -jar mwdumper.jar \ --output=bzip2:pages_public.xml.bz2 \ --format=xml \ --filter=notalk \ --filter=namespace:\!NS_USER \ --filter=latest \ --output=bzip2:pages_current.xml.bz2 \ --format=xml \ --filter=latest \ --output=gzip:pages_full_1.5.sql.gz \ --format=sql:1.5 \ --output=gzip:pages_full_1.4.sql.gz \ --format=sql:1.4 \ pages_full.xml.gz

A bare parameter will be interpreted as a file to read XML input from; if "-" or none is given, input will be read from stdin. Input files with ".gz" or ".bz2" extensions will be decompressed as gzip and bzip2 streams, respectively.

Internal decompression of 7-zip .7z files is not yet supported; you can pipe such files through p7zip's 7za:

7za e -so pages_full.xml.7z | java -jar mwdumper.jar --format=sql:1.5 | mysql -u -p.
 * The JRE does not allow you to mix the -jar and -classpath arguments (hence the different command structure).
 * The --output argument must before the --format argument.
 * The ampersand in the MySQL URI must be escaped on Unix-like systems.

Example of using mwdumper with a direct connection to MySQL on WindowsXP
Had problems with the example above... this following example works better on XP....

1.Create a batch file with the following text.

set class=mwdumper.jar;mysql-connector-java-3.1.12/mysql-connector-java-3.1.12-bin.jar set data="C:\Documents and Settings\All Users.WINDOWS\Documents\en.wiki\enwiki-20060207-pages-articles.xml.bz2" java -client -classpath %class% org.mediawiki.dumper.Dumper "--output=mysql://127.0.0.1/wikidb?user= &password= &characterEncoding=UTF8" "--format=sql:1.5" %data% pause

2.Download the mysql-connector-java-3.1.12-bin.jar and mwdumper.jar

3.Run the batch file.

Note
 * 1) It still reports a problem with the import files, "duplicate key"...
 * 2) The class path separator is a ; (semi-colon) in this example; different from the example above.

The "duplicate key" error may result from the page, revision and text tables in the database not being empty, or from character encoding problems. See A note on character encoding.

Performance Tips

 * Please elaborate on these tips if you can.

To speed up importing into a database, you might try the following:

Remove indexes and auto-increment fields
Temporarily remove all indexes and auto_increment fields from the following tables: page, revision and text. This gives a tremendous speed bump, because MySQL will otherwise be updating these indexes after each insert.

Don't forget to recreate the indexes afterwards. Note that it will take a long time to recreate all the removed data.
 * 1) Remove indexes:
 * 2) * You can use the procedure from http://www.javaquery.com/2014/03/mysql-queries-to-show-all-database.html to remove indexes. Execute multiple times and check with "show index from page", etc. if the indexes are removed.
 * 3) Remove primary keys: In MySQL execute:
 * 4) * alter table revision drop primary key;
 * 5) * alter table text drop primary key;
 * 6) * alter table page drop primary key;
 * 7) Remove auto increment fields: In MySQL execute:
 * 8) * alter table revision change rev_id rev_id int(10) unsigned not null;
 * 9) * alter table text change old_id old_id int(10) unsigned not null;
 * 10) * alter table page change page_id page_id int(10) unsigned not null;

Set -server option
Java's -server option may significantly increase performance on some versions of Sun's JVM for large files. (Not all installations will have this available.)

Increase MySQL's innodb_log_file_size
Increase MySQL's innodb_log_file_size. The default is as little as 5mb, but you can improve performance dramatically by increasing this to reduce the number of disk writes. (See the my-huge.cnf sample config.)

Disable the binary log
If you don't need it, disable the binary log (log-bin option) during the import. On a standalone machine this is just wasteful, writing a second copy of every query that you'll never use.

To test if binary log is enabled via SQL command, issue the following statement:

SHOW VARIABLES LIKE 'log_bin';

More tips in the MySQL reference manual
Various other wacky tips can be found in the MySQL reference manual. If you find any useful ones, please write about them here.

Troubleshooting
If strange XML errors are encountered under Java 1.4, try 1.5:
 * http://java.sun.com/j2se/1.5.0/download.jsp
 * http://www.apple.com/downloads/macosx/apple/java2se50release1.html

If mwdumper gives java.lang.IllegalArgumentException: Invalid contributor exception, see 18328

If it gives java.lang.OutOfMemoryError: Java heap space exception, run it with larger heap size, for example  (first is starting, second maximum size) (bug 21937)

If an error is thrown with a reference to page_counter being missing, downgrading to an older version of the Wiki solved the issue as this column existed in the older version.

How to build MWDumper from source
You can build MWDumper from and let Maven sort out the dependencies. Just:

It should generate the  file (for example  ) on the folder named.

Reporting bugs
Bugs can be reported in the Wikimedia bug tracker.

Change history (abbreviated)

 * 2016-04-23: Updated Xerces library to fix intermittent UTF-8 breakage
 * ... various bug fixes ...
 * ... build system changed to Maven ...
 * ... various bug fixes ...
 * 2005-10-25: Switched SqlWriter.sqlEscape back to less memory-hungry StringBuffer
 * 2005-10-24: Fixed SQL output in non-UTF-8 locales
 * 2005-10-21: Applied more speedup patches from Folke
 * 2005-10-11: SQL direct connection, GUI work begins
 * 2005-10-10: Applied speedup patches from Folke Behrens
 * 2005-10-05: Use bulk inserts in SQL mode
 * 2005-09-29: Converted from C# to Java
 * 2005-08-27: Initial extraction code

Todo

 * Add some more junit tests
 * Include table initialization in SQL output
 * Allow use of table prefixes in SQL output
 * Ensure that titles and other bits are validated correctly.
 * Test XML input for robustness
 * Provide filter to strip ID numbers
 * &lt;siteinfo&gt; is technically optional; live without it and use default namespaces
 * GUI frontend(s)
 * Port to Python? ;)

Alternate method of loading a huge wiki

 * Warning: This method takes days to run.

If you have to load a huge wiki this might help...

Below is a set of instructions that makes loading a large wiki less error prone and maybe a bit faster. It is not a script but rather a set of commands you can copy into bash (running in a screen session.) You'll have to babysit and customize the process for your needs.


 * 1) Dump SQL to disk in even sized chunks.  This takes about 80 Gb of hard drive space and 3 hours for enwiki.
 * 2) Setup the db to receive the chunks.  This takes a few seconds.
 * 3) Import the chunks.  This takes a few days for enwiki.
 * 4) Rebuild the DB.  This takes another day for enwiki.
 * 5) Run standard post import cleanup.  I haven't finished this step successfully yet but some of it can be skipped I think.

export DUMP_PREFIX=/public/datasets/public/enwiki/20130604/enwiki-20130604 export DIR_ROOT=/data/project/dump export DIR=${DIR_ROOT}/enwiki export EXPORT_PROCESSES=4 export IMPORT_PROCESSES=4 export DB=enwiki2 export EXPORT_FILE_SIZE=5 export EXPORT_FILE_SUFFIX_LENGTH=8 export LOG=~/log

bash -c 'sleep 1 && echo y' | mysqladmin drop ${DB} -u root sudo rm -rf ${DIR} rm -rf ${LOG}

sudo mkdir -p ${DIR} sudo chown -R ${USER} ${DIR_ROOT} mkdir -p ${LOG}

sudo apt-get install openjdk-7-jdk libicu-dev -y #jdk for mwdumper and libicu-dev for uconv ls -1S ${DUMP_PREFIX}-pages-meta-current*.xml-p* | xargs -I{} -P${EXPORT_PROCESSES} -t bash -c ' mkdir -p ${DIR}/$(basename {}) cd ${DIR}/$(basename {}) bunzip2 -c {} | uconv -f UTF-8 -t ascii --callback escape-xml-dec -v 2> ${LOG}/$(basename {}).uconv | java -jar ~/mwdumper-1.16.jar --format=sql:1.5 2> ${LOG}/$(basename {}).mwdumper | grep INSERT | split -l ${EXPORT_FILE_SIZE} -a ${EXPORT_FILE_SUFFIX_LENGTH} 2> ${LOG}/$(basename {}).split '
 * 1) Dump SQL to disk in even sized chunks.
 * 2) Sort by size descending to keep as many threads as possible hopping.
 * 3) uconv cleans up UTF-8 errors in the source files.
 * 4) grep removes BEGIN and COMMIT statements that mwdumper thinks are good, but I do better below

mysqladmin create ${DB} --default-character-set=utf8 -u root mysql -u root ${DB} < /srv/mediawiki/maintenance/tables.sql mysql -u root ${DB} <<HERE ALTER TABLE page CHANGE page_id page_id INTEGER UNSIGNED, DROP INDEX name_title, DROP INDEX page_random, DROP INDEX page_len, DROP INDEX page_redirect_namespace_len; ALTER TABLE revision CHANGE rev_id rev_id INTEGER UNSIGNED, DROP INDEX rev_page_id, DROP INDEX rev_timestamp, DROP INDEX page_timestamp, DROP INDEX user_timestamp, DROP INDEX usertext_timestamp, DROP INDEX page_user_timestamp; ALTER TABLE text CHANGE old_id old_id INTEGER UNSIGNED; HERE
 * 1) Setup the db to receive the chunks.

echo 'BEGIN;' > ${DIR_ROOT}/BEGIN echo 'COMMIT;' > ${DIR_ROOT}/COMMIT find ${DIR} -type f | sort -R | xargs -I{} -P${IMPORT_PROCESSES} -t bash -c ' cat ${DIR_ROOT}/BEGIN {} ${DIR_ROOT}/COMMIT | mysql -u root ${DB} && rm {}'
 * 1) Import the chunks
 * 2) Each chunk is wrapped in a transaction and if the import succeeds the chunk is removed from disk.
 * 3) This means you should be able to safely ctrl-c the process at any time and rerun this block and
 * 4) it'll pick up where it left off.  The worst case scenario is you'll get some chunk that was added
 * 5) but not deleted and you'll see mysql duplicate key errors.  Or something like that.  Anyway, if you
 * 6) are reading this you are a big boy and can figure out how clean up the database or remove the file.

mysql -u root ${DB} < 1; UPDATE page, bad_page SET page.page_title = CONCAT(page.page_title, page.page_id) WHERE page.page_namespace = bad_page.page_namespace AND page.page_title = bad_page.page_title; DROP TABLE bad_page; ALTER TABLE page CHANGE page_id page_id INTEGER UNSIGNED AUTO_INCREMENT, ADD UNIQUE INDEX name_title (page_namespace,page_title), ADD INDEX page_random (page_random), ADD INDEX page_len (page_len), ADD INDEX page_redirect_namespace_len (page_is_redirect, page_namespace, page_len); ALTER TABLE revision CHANGE rev_id rev_id INTEGER UNSIGNED AUTO_INCREMENT, ADD UNIQUE INDEX rev_page_id (rev_page, rev_id), ADD INDEX rev_timestamp (rev_timestamp), ADD INDEX page_timestamp (rev_page,rev_timestamp), ADD INDEX user_timestamp (rev_user,rev_timestamp), ADD INDEX usertext_timestamp (rev_user_text,rev_timestamp), ADD INDEX page_user_timestamp (rev_page,rev_user,rev_timestamp); ALTER TABLE text CHANGE old_id old_id INTEGER UNSIGNED AUTO_INCREMENT; HERE
 * 1) Rebuild the DB

cd /srv/mediawiki php maintenance/update.php
 * 1) Run standard post import cleanup