On 06/29/2018 04:00 PM, Mai Peng wrote:
Hello,
On a pG10.4 instance, my query ( a simple select from a view) throw this
error:
ERROR: cannot start subtransactions during a parallel operation
CONTEXT: PL/pgSQL function check_validity(ltree[]) line 4 during
statement block entry
So, what does this check_validity function do? It's not part of
PostgreSQL, and it apparently tries to do something that opens a
subtransation. Like a SAVEPOINT for example ...
But prefixing this query by "set max_parallel_workers_gather=0" make it
works.
When I take off the column that is checked by a function, no need to add
set max_parallel_workers_gather=0 .
Well, that's not really surprising - if you disable parallelism the
query is no longer subject to the restriction about subtransactions.
How could I continue to use the default max_parallel_workers_gather (2).
Modity the function not to start a subtransaction.
regards
--
Tomas Vondra http://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
