Missing Backlinks / Moving doesn't update links

Help / Discuss
#1

The Backlink feature has stopped working on my Wiki.
Here’s a small example: These two pages link each other, but show no backlinks and moving one page breaks the link on the other:
backlink test

The links are proper doc: links created with the WYSIWG editor.
This Problem persists on my Production Wiki, which is on 14.10.4 and the QA Wiki which is on 15.5. It affects all pages. Backlinks are turned on in both instances and running $xwiki.refreshLinks() hasn’t changed anything.

Any clues on what could be causing this?

Regards,
Sett

#2

Hello @Sett,

(back)links are based on the page indexation (using solr).
Did you check the size of the indexation queue on the Search of the Admin?

#3

Hello @mleduc,

the indexation queue is on 0, I’ve also run a reindex before which didn’t resolve the issue.

#4

I also checked the Database, the xwikilinks Table is fully populated and when I import the pages of the production wiki to a fresh container on my local machine the preexisting backlinks work aswell. This issue is completely puzzling to me.

#5

I can confirm the exact same behavior in our wikis (multiple stages). We are running v14.10.4 in production currently and v15.5.1 in the other stages. The xwikilinks table is also fully populated, while no backlinks are displayed in the UI.

To troubleshoot this issue, I’ve also temporarily switched the search engine from Solr to database without any change in behavior. Reindexing Solr also does not yield any positive results. The issue also occurs in the main wiki as well as additional sub-wikis, both with local and global links.

If anyone has found a solution to this issue, I’d appreciate any tips.

#6

For anyone running into the same issue, we found the culprit after quite a bit of searching. The issue was caused by an incomplete update where the XWiki itself was updated, but Solr (or better the core schema) was not. To fix the issue, we simply purged our Solr and reinitialized it with the core schemas for the new XWiki version. We then restarted XWiki and started the reindexing process.

Background: somewhere between XWiki 14.4 and 14.10 must have been a change that moved some logic (especially regarding the backlinks) from the database into Solr (I think it was 14.8, but not sure). The database still contains all the backlinks and replicating them into Solr is not an issue; however, without the required fields in the Solr schema, the backlinks are simply not indexed and cannot be found later on.

1 Like
#7

Thx for posting back!