Change of $page->parent is extremely slow

[Dennis Spohr]

Hi all,

when I update the parent of an existing page, this process takes extremely long (20-30 seconds).

$page->of(false);
$page->parent = $trash;
$page->save();

Sometimes these tested pages doesn't even have a single child-page.

Our database is quite large (but with a very fast server):

• 900.000 entries in the pages table.
• 90.000 entries in the pages_parents table.

Is there any other way to change the parent or does anybody now where this could come from?

We have multiple places where this is happening now.

Thanks!
Dennis

[adrian]

Is it only slow when changing the parent to trash, or slow in general?

Instead of that approach to trashing pages, have you tried:

$page->trash();

https://processwire.com/api/ref/page/trash/

[Dennis Spohr]

Changing the parent is slow in general. In my case $trash is my own custom page, not the trash of ProcessWire. 

I have other places in my code where I change the parent not using my own trash and there I have the same behaviour.

[adrian]

What version of PW are you running? In 3.0.156 there were a bunch of changes related to page parents: 

I am wondering if these changes might help, or if you are already running this (or later version), if it was faster before?

[Dennis Spohr]

I am running PW 3.0.165, the latest master version. 
Unfortunately I can’t tell if it was faster before migrating to this version. Sometimes it was kind of slow, but I didn’t look into this in detail before.

Today we figured out another problem with parents. When using $page->find() sometimes it doesn’t find an existing page (with $pages->find() it’s there). In this case it has to be something with the has_parent selector. After at least 20 minutes of testing and debugging, it was finally working without us changing anything.

Probably the pages_parent table is not working correctly or is created/updated too late. But this doesn’t fix the first issue regarding the performance.

Something strange is going on.

[adrian]

Perhaps it's worth trying the new: $pages->parents()->rebuildAll(); 

https://github.com/processwire/processwire/blob/d3b1ab2983108a0410f7c66997f0478e7f3e02e6/wire/core/PagesParents.php#L580

Obviously a DB backup before doing this is essential, or do it on a dev copy of the site.

[Dennis Spohr]

$pages->parents()->rebuildAll() took around 16 seconds on our dev-server.

For now we switched back to pw 3.0.148 and it seems that the error is not happening anymore.
Also changing the parent is not as slow anymore.

So there's definetely something going on with this new pages_parents table, but we were not able to reproduce the error with $page->find() on purpose.
It randomly happened and for sure the pages_parents table was not correct anymore. But somehow fixed after seconds or minutes.

[adrian]

Hi @Dennis Spohr - thanks for testing all that. Would you mind posting a issue on Github so that @ryan can track this. Please include a link to this thread.

[Dennis Spohr]

Sure, just posted it here: https://github.com/processwire/processwire-issues/issues/1297

[lpa]

Could you disable the rebuildAll() call for a moment in PagesParents.php, or would it break something? Will it rebuild the indexes after it would be reenabled?

Quote

We've isolated the issue to line 502 of PagesParents.php, where $this->rebuildAll() is called when the page is moved.

 

[Dennis Spohr]

This issue is fixed in the latest commit. ?