preg_match(): Compilation failed at wp-db.php on line 1657

Resolved RWall
(@rwall)

6 years, 5 months ago

After updating to V4.9, I had this error message on every page:

Warning: preg_match(): Compilation failed: unrecognized character after (?< at offset 4 in [host url]/website/wp-includes/wp-db.php on line 1657

And slightly more on the dashboard (cut off by the theme):

…mpilation failed: unrecognized character after (?< at offset 4 in [host url]/website/wp-includes/wp-db.php on line 1657

Warning: Cannot modify header information – headers already sent by (output started at [host url]/website/wp-includes/wp-db.php:1657) in [host url]/website/wp-admin/includes/misc.php on line 1114

Can anyone suggest the cause and the fix?
I see someone else asked about exactly the same error message at WordPress.com. I’ve rolled back to V4.8.3 in the meantime, but plugins, theme & content are all the same, all remained in place and not reloaded.

The page I need help with: [log in to see the link]

Viewing 15 replies - 16 through 30 (of 43 total)

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crkm
(@crkm)

6 years, 5 months ago

@rwall
Thanks for the reply. I run and moderate a couple of websites and fully appreciate your comments. While not chartered I too am an Engineer and know what PHP is but little more.
To reiterate, upgrading to WP 4.9 broke (or at least severely impaired) one of the websites I look after. (I have not updated any of the other websites to WP 4.9.) In search of help, I ended up in this thread where you appear to have experienced the same problem, i.e. the warning with the reference to line 1657 in wp-db.php.
I (like you) have now downgraded back to WP 4.8.3 on the site I had upgraded to WP 4.9. The website is now working fine again.
Thread Starter RWall
(@rwall)

6 years, 5 months ago
@crkm
You’re not “drt102” who asked at the WordPress.com forum and got told to go away? If you aren’t, then there are three known instances of this problem, and it’s hard to believe that three of us use the same hosting provider, or are using the hosting providers that send the same wrongly constructed headers.
I use Easily.co.uk.

[Edit]
I wrote “three known instances” – wrong! Try a Google search for “wp-db.php on line 1657”.
There are at least 5 more instances there – that weren’t there when I first posted. So they are crawling out of the woodwork as more people update, and it’s not quite as isolated as first appeared.
- This reply was modified 6 years, 5 months ago by RWall.
crkm
(@crkm)

6 years, 5 months ago

@rwall
I’m not drt102. The site with which I have had the problems is hosted by Easily.co.uk! The other sites are hosted elsewhere so I’ll try an upgrade to WP 4.9 and see what happens.
Thanks for the heads-up about the other instances.

crkm
(@crkm)

6 years, 5 months ago

@rwall
I updated a site not hosted by Easily to WP 4.9…. no problem, no warnings. The other thing I noted is that all the results from the Google search you suggest contain …./web1/userxxxxx/website/… where the x’s are numbers (4 or 5). This format is the one used by Easily for hosting (my other sites use a different format). So it suggests (but not conclusively) that the websites suffering from this warning after the upgrade to WP 4.9 are from a particular host which brings me back to thinking it is a php version issue.
I suggest we turn our attention to our host!

Thread Starter RWall
(@rwall)

6 years, 5 months ago

@crkm
Can you raise a ticket with Easily? I can’t because the owner has changed the control panel password and hasn’t come back to me yet with the new one. You can point them to http://www.hannahleightonboyce.com if it helps (not that it’s likely to as we have the identical problem).
crkm
(@crkm)

6 years, 5 months ago
@rwall
Will do (or rather have done). If I hear back, I’ll let you know.
ps I like your site, it is about as different from curtc.net as you can get!
- This reply was modified 6 years, 5 months ago by crkm.
pete5000
(@pete5000)

6 years, 5 months ago

Hi, I’m just a common or garden blog user with two 8 year old blogs on .org and have never had a problem before.

At the moment one of them is showing the line 1657 error and I can’t log in. The error is public on the top of the page to all viewers.

Can you advise if a fix from WordPress via an automatic update is likely soon or do I need to manually re-upload it. I don’t do regular updates so can wait if one is coming.

Regards
Peter

pete5000
(@pete5000)

6 years, 5 months ago

Hi,
I’ve just read the page 2 comments and notice Easily being mentioned. My sites are on Easily.

Regards
Peter

Moderator t-p
(@t-p)

6 years, 5 months ago

I have updated my site — and millions and millions others — without such issue.

The issue all of you are have, the common thread is your hosting provider Easily.

So, my suggestion is to get in touch with your hosting provider to resolve this issue.

dpfavand
(@dpfavand)

6 years, 5 months ago

I agree, this appears to be related to Easily as we had this issue upgrading http://www.scottishrecordsociety.org.uk/ to 4.9. We will be contacting them regarding this.

Thread Starter RWall
(@rwall)

6 years, 5 months ago

@pete5000
I get the impression that a fix from WordPress.org is unlikely, even though it looks very much like a backwards-compatibility issue.

My personal recommendation is to download V4.8.3 from https://wordpress.org/wordpress-4.8.3.zip, and upload to your site the directories wp-admin, wp-includes and the root files but excluding your wp-config.php and your wp-content directory, as t-p instructed for V4.9 on page 1 of this thread.

Can everyone then please raise a ticket with Easily and refer them to this thread, as there’s strength in numbers.

pete5000
(@pete5000)

6 years, 5 months ago

Hi, I raised an on line query with Easily mid afternoon referring to this thread.

It seems strange there isn’t backwards compatibility of the WordPress update as the blog I didn’t update is still working.

Also the blog seemed alright after I updated it last Friday as I made a post and didn’t notice any errors.

The update seemed to take a long time and seemed a bit suspect, I recall.

Thread Starter RWall
(@rwall)

6 years, 5 months ago

Very interestingly, Wordfence is reporting a directory traversal attack on the faulty file – attacks started on 18th November at 21:23 and continued over the weekend and today.

My update too seemed suspect, but it didn’t leave the “maintenance” file behind. I’ve no idea whether the ‘no content’ (from memory ?) parameter uploads everything that t-p instructed, or whether it is more selective, so I don’t think the time it took is a reliable indication.

My site owner says she has just raised a ticket too.
pete5000
(@pete5000)

6 years, 5 months ago
@rwall

Is it likely that if we all overwrite our update that it will be harder to find the problem.

If Easily don’t reply by lunchtime I’ll ring them up. I’m one click ready with the 4.8.3 upload.
- This reply was modified 6 years, 5 months ago by pete5000.
Pioneer Web Design
(@swansonphotos)

6 years, 5 months ago

Deciding to opt out of a discussion of support matters. Deciding to return also is. This thread has gone from an issue not related to almost all to what I can only now see as an affront to helping the WP community properly.

1. Each time a major release is made available, the dashboard (along with well known site responsibilities), includes important warnings about backing up your site(s).

2. WordPress.org is not your hosting provider. If a specific host has issues, please review the hosting recommendations.

3. If you think this is an issue with a WordPress Plugin, then the proper support channel for help with such issues is at their support page. A simple search will find the plugin of question.

Again, millions of sites have not experienced the issues noted here.

Tips:

Please help yourself and your site clients by finding a web host that starts with Job One (Security).

WordPress is not based simply on files. Simply changing a set of files does not affect the MySQL DB. Please all review the Codex for proper details. It’s also not new.