Re: What could cause CREATE TEMP... "could not read block" error?

On 11/20/2015 06:18 AM, Albe Laurenz wrote:
> Chris Richards wrote:
>> Howdy. I have two tables that I'm joining together and using the result to create a temporary table.
>> Performing the join operation works fine; it produces 0 rows (as expected). If I prepend "CREATE TEMP
>> tmp_policyqueue AS" to the SELECT then it generates this error:
>>
>> ERROR:  could not read block 39 in file "base/16391/11937": read only 0 of 8192 bytes
>>
>>
>> $ psql
>> psql (9.3.9)
>>
>> mdb=> CREATE TEMP TABLE tmp_policyqueue AS
>>
>> mdb-> SELECT pq.* FROM policyqueue AS pq
>> mdb-> JOIN seed_progress AS sp ON pq.id=sp.polidx;
>> ERROR:  could not read block 40 in file "base/16391/11937": read only 0 of 8192 bytes
>>
>> You'll also observe that the block number is changing each time I execute the command. I know very
>> little about postgres internal structure so it may be irrelevant. I've left my database in this state
>> should extra information be needed.
>
> It would be interesting to know what object is affected:
>
> SELECT s.nspname AS schemaname, t.relname AS objectname, t.relkind
> FROM pg_class t JOIN
>       pg_namespace s ON t.relnamespace = s.oid
> WHERE t.relfilenode = 11937;
>
> If it is an index, REINDEX should help.
>
> What is the statement that performs the join operation and works just fine?

If I am following correctly it is:

mdb-> SELECT pq.* FROM policyqueue AS pq
mdb-> JOIN seed_progress AS sp ON pq.id=sp.polidx;

>
> Yours,
> Laurenz Albe
>


--
Adrian Klaver
adrian.klaver@aklaver.com