Re: SQL/PostgreSQL - Error observed in the QUERY not caught by the “EXCEPTION” block in the stored procedure - Mailing list pgsql-bugs
"We've fixed a few bugs over the years that manifest in that type of
problem --- are you up to date on minor releases? It's also possible
that reindexing that toast table would fix it."
->
Yes. I already tried reindexing. Only a few records were recovered, others had to be deleted. The version of PG I use is "10.X".
"I think that plpgsql will not bother to dereference a TOAST pointer
when storing it into a local variable (although this statement is
very possibly version-dependent, and you didn't say what PG version
you are using).
A more reliable way to trigger the problem is to do some computation
that requires the value of the field, perhaps along the lines of.
[...]
I don't know that I'd give a procedure like this license to delete my
entire table :-(. If you really don't care how much data survives,
why not just TRUNCATE the table and be done with it? Otherwise,
printing the list of troublesome rows for manual review seems way
more prudent."
->
Thanks for the suggestions! I found it a bit strange "pgsql" not to "understand" as an exception the "ERROR: missing chunk number 0 for toast value 3483039 in pg_toast_3473493". I also noticed that the "pgsql" returns a code other than "0" when this error occurs. Finally, my only option was to use this customizable bash script https://stackoverflow.com/a/59770772/3223785 that I created to work around the problem. Note that this bash script also uses the pgsql return code (see excerpt "if [[ ${F_GET_EXIT_CODE_R} -ne 0 ]] && [[ $F_GET_STDERR_R == *" chunk number "* ]]; then") to address the issue. For all that can be observed this problem really seems to me a bug.
Thanks! =D
problem --- are you up to date on minor releases? It's also possible
that reindexing that toast table would fix it."
->
Yes. I already tried reindexing. Only a few records were recovered, others had to be deleted. The version of PG I use is "10.X".
"I think that plpgsql will not bother to dereference a TOAST pointer
when storing it into a local variable (although this statement is
very possibly version-dependent, and you didn't say what PG version
you are using).
A more reliable way to trigger the problem is to do some computation
that requires the value of the field, perhaps along the lines of.
[...]
I don't know that I'd give a procedure like this license to delete my
entire table :-(. If you really don't care how much data survives,
why not just TRUNCATE the table and be done with it? Otherwise,
printing the list of troublesome rows for manual review seems way
more prudent."
->
Thanks for the suggestions! I found it a bit strange "pgsql" not to "understand" as an exception the "ERROR: missing chunk number 0 for toast value 3483039 in pg_toast_3473493". I also noticed that the "pgsql" returns a code other than "0" when this error occurs. Finally, my only option was to use this customizable bash script https://stackoverflow.com/a/59770772/3223785 that I created to work around the problem. Note that this bash script also uses the pgsql return code (see excerpt "if [[ ${F_GET_EXIT_CODE_R} -ne 0 ]] && [[ $F_GET_STDERR_R == *" chunk number "* ]]; then") to address the issue. For all that can be observed this problem really seems to me a bug.
Thanks! =D
Em sex., 17 de jan. de 2020 às 01:30, Tom Lane <tgl@sss.pgh.pa.us> escreveu:
Eduardo Lúcio Amorim Costa <eduardolucioac@gmail.com> writes:
> my_database=# SELECT file INTO my_file_now FROM public.my_datatable WHERE
> my_id='2fdf5297-8d4a-38bc-bb26-b8a4b7ba47ec';
> ERROR: missing chunk number 0 for toast value 3483039 in pg_toast_3473493
We've fixed a few bugs over the years that manifest in that type of
problem --- are you up to date on minor releases? It's also possible
that reindexing that toast table would fix it.
> Based on the above behavior I created the following stored procedure:
> ...
> my_file_now BYTEA;
> ...
> SELECT file
> INTO my_file_now
> FROM public.my_datatable WHERE my_id=my_id_now;
> QUESTION: Why is the error observed in the query not caught by the
> "EXCEPTION" block in the stored procedure?
I think that plpgsql will not bother to dereference a TOAST pointer
when storing it into a local variable (although this statement is
very possibly version-dependent, and you didn't say what PG version
you are using).
A more reliable way to trigger the problem is to do some computation
that requires the value of the field, perhaps along the lines of
PERFORM md5(file) FROM public.my_datatable WHERE my_id=my_id_now;
> EXCEPTION
> WHEN OTHERS THEN
> RAISE NOTICE 'CORRUPTED MY_ID - % ', my_id_now;
> DELETE FROM public.my_datatable WHERE my_id=my_id_now;
I don't know that I'd give a procedure like this license to delete my
entire table :-(. If you really don't care how much data survives,
why not just TRUNCATE the table and be done with it? Otherwise,
printing the list of troublesome rows for manual review seems way
more prudent.
regards, tom lane
Eduardo Lúcio
LightBase Consultoria em Software Público
+55-61-3347-1949 - http://brlight.org - Brasil-DF
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