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Recovering an old MediaWiki Database

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Written by charlie

Category: Other

Published: 15 January 2016

Created: 15 January 2016

Last Updated: 15 August 2017

In 2011, I permanently shut down the Wetland Wiki, as the workload of constantly editing and updating the pages became onerous, and Wikipedia had much of the same, if less detailed, information. Before shutting it down, I copied the Mediawiki (Version 1.13.1) database for posterity, and occasionally thought that some of the pages/articles I wrote should not have just disappeared, but been shared in some other fashion. 5 years later, almost to the day, I tried importing the database, and ran into many unforeseen errors, primarily due to depreciated syntax and changes in MySQL - my database hadn’t changed, but the MySQL has changed enough to make importing the database impossible without some updates.

Below are the errors I encountered while importing them into PhpMyAdmin, and how I fixed them; maybe someone else will find them useful. These few changes allowed me to import the 25MB database with approximately 200,000 lines successfully. The first error I encountered was:

#1064 - You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'TYPE=MyISAM' at line 8.

'TYPE=MyISAM' is depreciated, so I searched and replaced over 20 occurrences with "ENGINE=MyISAM". In a closely related error, 'TYPE=InnoDB" was also replaced with "ENGINE=InnoDB".

At this point about 20% of the database was imported successfully until the following error:

#1426 - Too big precision 14 specified for 'cl_timestamp'. Maximum is 6. which was easily corrected to timestamp(6) CREATE TABLE `categorylinks` (
`cl_from` int(8) unsigned NOT NULL default '0',
`cl_to` varchar(255) binary NOT NULL default '',
`cl_sortkey` varchar(86) binary NOT NULL default '',
`cl_timestamp` timestamp(14) NOT NULL,
UNIQUE KEY `cl_from` (`cl_from`,`cl_to`),
KEY `cl_timestamp` (`cl_to`,`cl_timestamp`),
KEY `cl_sortkey` (`cl_to`,`cl_sortkey`,`cl_from`)
) ENGINE=InnoDB

The last error recieved was, #1064 - You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'TYPE=HEAP MAX_ROWS=25000' at line 3. Which I updated to 'ENGINE=HEAP MAX_ROWS=25000'

Additionally, PhpMyAdmin had been timing out while importing the database after a few minutes. To lengthen the amount of time available for the import, I added the following line $cfg['ExecTimeLimit'] = 6000; to config.inc.php and restarted Apache.

After all this, the entire 25MB database was imported successfully. Now all I have to do is extract the articles, but that’s for another post!

GIS Presentations

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Written by charlie

Category: Low Cost Mapping

Published: 14 January 2016

Created: 14 January 2016

Last Updated: 15 August 2017

I found the following Open Source GIS related presentations written by GreenWood map over the past 2 years informative, especially the Parcel Mapping complexities found in Wyoming.

• Skeletonizing Polygons Using PostGIS
• Cartography and Topology
• Parcel Mapping WyGEO Meeting
• Simplifying Geomoetries Using Open Source Tools

The presentations are available on the Greenwood website.