Enable parallel query by default.
Change max_parallel_degree default from 0 to 2. It is possible that this is not a good idea, or that we should go with 1 worker rather than 2, but we won't find out without trying it. Along the way, reword the documentation for max_parallel_degree a little bit to hopefully make it more clear. Discussion: 20160420174631.3qjjhpwsvvx5bau5@alap3.anarazel.de
This commit is contained in:
parent
b7351ced42
commit
77cd477c4b
|
@ -2005,10 +2005,14 @@ include_dir 'conf.d'
|
|||
</term>
|
||||
<listitem>
|
||||
<para>
|
||||
Sets the maximum degree of parallelism for an individual parallel
|
||||
operation. Note that the requested number of workers may not actually
|
||||
be available at runtime. Parallel workers are taken from the pool
|
||||
of processes established by <xref linkend="guc-max-worker-processes">.
|
||||
Sets the maximum number of workers that can be started for an
|
||||
individual parallel operation. Parallel workers are taken from the
|
||||
pool of processes established by
|
||||
<xref linkend="guc-max-worker-processes">. Note that the requested
|
||||
number of workers may not actually be available at runtime. If this
|
||||
occurs, the plan will run with fewer workers than expected, which may
|
||||
be inefficient. The default value is 2. Setting this value to 0
|
||||
disables parallel query.
|
||||
</para>
|
||||
</listitem>
|
||||
</varlistentry>
|
||||
|
|
|
@ -113,7 +113,7 @@ int effective_cache_size = DEFAULT_EFFECTIVE_CACHE_SIZE;
|
|||
|
||||
Cost disable_cost = 1.0e10;
|
||||
|
||||
int max_parallel_degree = 0;
|
||||
int max_parallel_degree = 2;
|
||||
|
||||
bool enable_seqscan = true;
|
||||
bool enable_indexscan = true;
|
||||
|
|
|
@ -2662,7 +2662,7 @@ static struct config_int ConfigureNamesInt[] =
|
|||
NULL
|
||||
},
|
||||
&max_parallel_degree,
|
||||
0, 0, MAX_BACKENDS,
|
||||
2, 0, MAX_BACKENDS,
|
||||
NULL, NULL, NULL
|
||||
},
|
||||
|
||||
|
|
|
@ -167,7 +167,7 @@
|
|||
|
||||
#effective_io_concurrency = 1 # 1-1000; 0 disables prefetching
|
||||
#max_worker_processes = 8
|
||||
#max_parallel_degree = 0 # max number of worker processes per node
|
||||
#max_parallel_degree = 2 # max number of worker processes per node
|
||||
#old_snapshot_threshold = -1 # 1min-60d; -1 disables; 0 is immediate
|
||||
# (change requires restart)
|
||||
#backend_flush_after = 0 # 0 disables,
|
||||
|
|
Loading…
Reference in New Issue