PG::StringDataRightTruncation (ERROR: value too long for type character varying(500) )

andrei · June 2, 2021, 11:32am

@chrispanag the problem is solved now:

github.com/discourse/discourse

FIX: PG::StringDataRightTruncation when linking posts

discourse:master ← discourse:fix/string-data-right-truncation-when-linking-posts

opened 11:51AM - 25 May 21 UTC

AndrewPrigorshnev

+48 -1

Users who use encoded slugs on their sites sometimes [run into 500 error](https:…//meta.discourse.org/t/pg-stringdatarighttruncation-error-value-too-long-for-type-character-varying-500/182426) when pasting a link to another topic in a post. The problem happens when generating a backward "reflection" link that would appear in a linked topic: <img width="400" alt="Screenshot 2021-05-25 at 16 11 53" src="https://user-images.githubusercontent.com/1274517/119496067-29330e80-bd74-11eb-8883-87d71108b4e0.png"> Link URL restricted on the database level to 500 chars in length. At first glance it should work since we have a restriction on topic title length: <img width="450" alt="Screenshot 2021-05-24 at 17 56 24" src="https://user-images.githubusercontent.com/1274517/119494745-b2494600-bd72-11eb-8bdc-a3e70c62fdf4.png"> But it doesn't work when a site uses encoded slugs, like [here](https://rembetiko.gr/t/%CE%B2%CF%81%CE%AE%CE%BA%CE%B1-%CE%BA%CE%AC%CF%84%CE%B9-%CE%B3%CE%B9%CE%B1-%CE%BC%CE%AD%CE%BD%CE%B1-%CF%84%CE%BF-%CF%81%CE%B5%CE%BC%CF%80%CE%AD%CF%84%CE%B9%CE%BA%CE%BF-%CF%84%CF%81%CE%B1%CE%B3%CE%BF%CF%8D%CE%B4%CE%B9-%CE%B5%CE%AF%CE%BD%CE%B1%CE%B9-%CE%BA%CE%B1%CF%84%CE%AC-%CE%B2%CE%AC%CF%83%CE%B9%CE%BD-%CE%B1%CF%81%CE%BC%CE%BF%CE%BD%CE%B9%CE%BA%CE%BF-%CE%BA%CE%B1%CE%B9-%CE%B4%CE%B9%CE%AC-%CF%84%CE%BF%CF%8D%CF%84%CE%BF-%CF%80%CE%BF%CE%BB%CF%85%CF%86%CF%89%CE%BD%CE%B9%CE%BA%CE%BF/42000) (take a look at the URL). The link to a topic, in this case, can be much longer than 500 characters. By the way, an error happens only when generating a "reflection" link and doesn't happen with a direct link, we [truncate that link](https://github.com/discourse/discourse/blob/6e2ecf40c7456a1af7f6470d09921f0138fbd4bb/app/models/topic_link.rb#L309). It works because, in this case, the original long link is still present in the post body and can be used for navigation. But we can't do the same for backward "reflection" links (without rewriting their implementation), the whole link must be saved to the database. The simplest and cleanest solution will be just to remove the restriction on the database level. Abuse is impossible here since we are already protected by the restriction on topic title length. There aren’t performance benefits in using length-constrained columns in Postgres, in fact, length-constrained columns need a few extra CPU cycles to check the length when storing data ([doc](https://www.postgresql.org/docs/9.3/datatype-character.html)).

As you said, the error was happening when generating a backward link from the linked post to the original post if the original post had a long title.

Topic		Replies	Views
Topic with Japanese in URL doesn't redirect if URL doesn't perfectly match bug	72	3518	October 21, 2019
Long links break the click tracker bug	12	1997	July 2, 2021
500 Error While Posting a Topic bug	16	749	August 6, 2020
Trouble with `discourse remap` remapping `topic_links url` bug	7	1329	February 28, 2019
Problem with post revisions after updating to 2.8.6 stable or 2.9.0.beta7 bug	41	2295	October 1, 2022

PG::StringDataRightTruncation (ERROR: value too long for type character varying(500) )

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