Special:Import throws error when importing XML from Wikipedia: "MediaWiki::preOutputCommit: Flushing an explicit transaction, getting out of sync!"
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	Devi59
	May 16 2017, 12:23 AM

Description

When I try to import an XML from Wikipedia the following error occurs.

[WRpFtI8ZhEL7icy9RCH3TgAAAAQ] /MediaWiki/index.php?title=Special:Import&action=submit DBUnexpectedError from line 2668 of /var/www/html/MediaWiki/includes/db/Database.php: MediaWiki::preOutputCommit: Flushing an explicit transaction, getting out of sync!
Backtrace:
#0 /var/www/html/MediaWiki/includes/db/loadbalancer/LoadBalancer.php(1055): DatabaseBase->commit(string, string)
#1 [internal function]: LoadBalancer->commitMasterChanges(string)
#2 /var/www/html/MediaWiki/includes/db/loadbalancer/LBFactory.php(206): call_user_func_array(array, array)
#3 [internal function]: LBFactory->{closure}(LoadBalancer, string, array)
#4 /var/www/html/MediaWiki/includes/db/loadbalancer/LBFactorySimple.php(154): call_user_func_array(Closure, array)
#5 /var/www/html/MediaWiki/includes/db/loadbalancer/LBFactory.php(209): LBFactorySimple->forEachLB(Closure, array)
#6 /var/www/html/MediaWiki/includes/db/loadbalancer/LBFactory.php(250): LBFactory->forEachLBCallMethod(string, array)
#7 /var/www/html/MediaWiki/includes/MediaWiki.php(561): LBFactory->commitMasterChanges(string, array)
#8 /var/www/html/MediaWiki/includes/MediaWiki.php(539): MediaWiki::preOutputCommit(RequestContext)
#9 /var/www/html/MediaWiki/includes/MediaWiki.php(750): MediaWiki->doPreOutputCommit()
#10 /var/www/html/MediaWiki/includes/MediaWiki.php(519): MediaWiki->main()
#11 /var/www/html/MediaWiki/index.php(43): MediaWiki->run()
#12 {main}

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Devi59 created this task.May 16 2017, 12:23 AM

Restricted Application added a subscriber: Aklapper. · View Herald TranscriptMay 16 2017, 12:23 AM

Wikipedia-20170512022422.xml264 KBDownload

This is specifically the XML I exported from Wikipedia that I am trying to import.

Which exact MediaWiki version is this about? (Also see https://mediawiki.org/wiki/How_to_report_a_bug )

Product Version
MediaWiki 1.27.1
PHP 5.6.30 (apache2handler)
MariaDB 10.1.23-MariaDB
Lua 5.1.5
BlueSpice (Credits) 2.27.1

Sorry about that I thought I had added that portion. I had reported it on BlueSpice but once we disabled that it was still present so I was told to report here.

Aklapper renamed this task from Special:Import throws out an error to Special:Import throws error when importing XML from Wikipedia: "MediaWiki::preOutputCommit: Flushing an explicit transaction, getting out of sync!".May 16 2017, 2:49 PM

Aklapper edited projects, added MediaWiki-Core-Snapshots; removed MediaWiki-Special-pages.

IS this being looked at?

Importing this XML file into a clean wiki with only Scribunto installed works fine for me in master (1.30.0-alpha) and in 1.27.1.

This looks like another one of those really annoying DB transaction Heisenbugs that we've been seeing over the years - I'm not sure who has been working on those.

In T165451#3371644, @Devi59 wrote:

IS this being looked at?

If there are no news published in a task, the answer to that is "no". :)

@Devi59 Can you reproduce this on MediaWiki 1.29 or later? A lot has changed with regards to transaction handling in the shutdown phase. I suspect his will have fixed itself by now.

Krinkle added a project: MW-1.31-release.Apr 10 2018, 3:21 PM

Krinkle moved this task from Backlog to Core on the MW-1.31-release board.Apr 18 2018, 6:08 PM

@Devi59: Could you please answer the last comment? Thanks!

I'm closing this based on T165451#4120522. I also tested it myself on MediaWiki master with the provided XML and was unable to reproduce. If you can still reproduce this on a supported MediaWiki version, please re-open.

Special:Import throws error when importing XML from Wikipedia: "MediaWiki::preOutputCommit: Flushing an explicit transaction, getting out of sync!"Closed, ResolvedPublicActions

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Special:Import throws error when importing XML from Wikipedia: "MediaWiki::preOutputCommit: Flushing an explicit transaction, getting out of sync!"
Closed, ResolvedPublic
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