Re: [PERFORM] Why Postgres use a little memory on Windows.

[tuanhoanganh]

Thanks for all help of everyone.

I have tried to change effective_cache_size = 24GB and it run well.

Tuan Hoang Anh

Re: [PERFORM] Why Postgres use a little memory on Windows.

[Jeff Janes]

On Sat, Feb 20, 2016 at 8:46 AM, tuanhoanganh  wrote:
> Hello
>
> I have a bad query on PostgreSQL 9.0.23 - 64bit - Windows 2012 R2 - 48GB Ram

9.0 is no longer supported.  You should work toward upgrading to a
newer version.  It might not solve this problem, but it would give you
better tools for diagnosing the problem.  Which is a pretty good step
toward solving it.

> When I check taskmanager, I found postgres process is user 4-5MB

Other people have explained the details of how the query is being run
and why it is being run that way.  But I would like to take a step
back from that, and tell you that the reason that PostgreSQL is not
using more memory, is that it doesn't think that using more memory
would help.

Cheers,

Jeff


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[PERFORM] Why Postgres use a little memory on Windows.

[tuanhoanganh]

Hello

I have a bad query on PostgreSQL 9.0.23 - 64bit - Windows 2012 R2 - 48GB Ram

explain analyze select d.data_id, d.table_name, d.event_type, d.row_data,
d.pk_data, d.old_data, d.create_time, d.trigger_hist_id, d.channel_id,
d.transaction_id, d.source_node_id, d.external_data, '' from sym_data d
inner join sym_data_gap g on g.status='GP' and d.data_id between g.start_id
and g.end_id where d.channel_id='sale_transaction' order by d.data_id asc;

Here is result

Nested Loop  (cost=319.42..4879348246.58 rows=32820035265 width=1525)
(actual time=64656.747..5594654.189 rows=3617090 loops=1)
  ->  Index Scan using sym_data_pkey on sym_data d
(cost=0.00..3671742.82 rows=3867095 width=1525) (actual
time=9.775..12465.153 rows=3866359 loops=1)
Filter: ((channel_id)::text = 'sale_transaction'::text)
  ->  Bitmap Heap Scan on sym_data_gap g  (cost=319.42..1133.51
rows=8487 width=8) (actual time=1.438..1.439 rows=1 loops=3866359)
Recheck Cond: ((d.data_id >= g.start_id) AND (d.data_id <= g.end_id))
Filter: (g.status = 'GP'::bpchar)
->  Bitmap Index Scan on sym_data_gap_pkey  (cost=0.00..317.30
rows=8487 width=0) (actual time=1.436..1.436 rows=1 loops=3866359)
  Index Cond: ((d.data_id >= g.start_id) AND (d.data_id <=
g.end_id))

http://explain.depesz.com/s/c3DT


I have run vaccum full. Here is my PostgreSQL config

shared_buffers = 2GB
work_mem = 64MB
maintenance_work_mem = 1GB
wal_buffers = 256
effective_cache_size = 4GB
checkpoint_segments = 256
wal_level = hot_standby
max_wal_senders = 5
wal_keep_segments = 256
random_page_cost = 3.5
autovacuum_vacuum_threshold = 1000
autovacuum_analyze_threshold = 250
max_locks_per_transaction = 2000

When I check taskmanager, I found postgres process is user 4-5MB

What happened with my PostgreSQL. Please help me

Thank you in advance.

Tuan Hoang Anh