Re: ERROR: unexpected chunk number 0 (expected 1) for toast value76753264 in pg_toast_10920100

We are seeing these "ERROR:  unexpected chunk number 0 (expected 1) for
toast value 1498303849 in pg_toast_10919630" in increasing numbers again¹.

An observation is that they seem to only happen for tsvector fields.

Here is an example sequence of queries for a record (we have more than a
handful of these currently), which exhibits the problem.

First we get two other fields, 'sequence' is large enough to be toast'ed:

  2018-01-16 08:51:17.362 efam=# select id,sequence from efam.sequence where id = 164504550;
  Time: 1.150 ms

No problem.

Then we also fetch the tsvector field:

  2018-01-16 08:51:27.773 efam=# select id,sequence,fts from efam.sequence where id = 164504550;
  ERROR:  unexpected chunk number 0 (expected 1) for toast value 1498303849 in pg_toast_10919630
  Time: 0.912 ms

And we get the error.

Getting the id and the tsvector:

  2018-01-16 08:51:34.174 efam=# select id,fts from efam.sequence where id = 164504550;
  ERROR:  unexpected chunk number 0 (expected 1) for toast value 1498303849 in pg_toast_10919630
  Time: 6.138 ms

gives the error.

Just getting the tsvector:

  2018-01-16 08:51:40.066 efam=# select fts from efam.sequence where id = 164504550;
  ERROR:  unexpected chunk number 0 (expected 1) for toast value 1498303849 in pg_toast_10919630
  Time: 1.805 ms

Gives the error.

Field definitions:

   id                                        | integer                     |
   sequence                                  | text                        |
   fts                                       | tsvector                    |

Maybe the observation that this only happens (for us) on tsvector rings
a bell for someone?


  Best regards,

    Adam


¹ As reported back in June, 2017, starting here:
  https://www.postgresql.org/message-id/7pefuv53dl.fsf%40novozymes.com
  (I have to admit I never got around to trying to revert the commit
  Alvaro Herrera suggested we try without
  (https://www.postgresql.org/message-id/20170611033840.hruqadsk47qcdrqb%40alvherre.pgsql))

--
 "No more than that, but very powerful all the                Adam Sjøgren
  same; simple things are good."                        adsj@novozymes.com