Re: Abnormal performance difference between Postgres and MySQL - Mailing list pgsql-performance
| From | Farhan Husain |
|---|---|
| Subject | Re: Abnormal performance difference between Postgres and MySQL |
| Date | |
| Msg-id | 3df32b6d0902251105n359cd198y3bfda1113ab1d6fb@mail.gmail.com Whole thread Raw |
| In response to | Re: Abnormal performance difference between Postgres and MySQL (Robert Haas <robertmhaas@gmail.com>) |
| Responses |
Re: Abnormal performance difference between Postgres and
MySQL
Re: Abnormal performance difference between Postgres and MySQL Re: Abnormal performance difference between Postgres and MySQL |
| List | pgsql-performance |
On Wed, Feb 25, 2009 at 12:58 PM, Robert Haas <robertmhaas@gmail.com> wrote:
Just start up psql and type:
show work_mem;
(You could look in the config file too I suppose.)
...Robert
On Wed, Feb 25, 2009 at 1:53 PM, Farhan Husain <russoue@gmail.com> wrote:
>
>
> On Wed, Feb 25, 2009 at 12:49 PM, Robert Haas <robertmhaas@gmail.com> wrote:
>>
>> You still haven't answered the work_mem question, and you probably
>> want to copy the list, rather than just sending this to me.
>>
>> ...Robert
>>
>> On Wed, Feb 25, 2009 at 1:34 PM, Farhan Husain <russoue@gmail.com> wrote:
>> >
>> >
>> > On Tue, Feb 24, 2009 at 8:21 PM, Robert Haas <robertmhaas@gmail.com>
>> > wrote:
>> >>
>> >> >> Can you please elaborate a bit?
>> >> >
>> >> > I thought that A0.Prop would ignore the composite index created on
>> >> > the
>> >> > columns subj and prop but this does not seem to be the case.
>> >>
>> >> Yeah, I think you're barking up the wrong tree here. I think Tom had
>> >> the correct diagnosis - what do you get from "show work_mem"?
>> >>
>> >> What kind of machine are you running this on? If it's a UNIX-ish
>> >> machine, what do you get from "free -m"and "uname -a"?
>> >>
>> >> ...Robert
>> >
>> > Here is the machine info:
>> >
>> > Machine: SunOS 5.10 Generic_127111-11 sun4u sparc SUNW, Sun-Fire-880
>> > Memory: 4 GB
>> > Number of physical processors: 2
>> >
>> >
>> > --
>> > Mohammad Farhan Husain
>> > Research Assistant
>> > Department of Computer Science
>> > Erik Jonsson School of Engineering and Computer Science
>> > University of Texas at Dallas
>> >
>
> Did you mean the work_mem field in the config file?
>
>
> --
> Mohammad Farhan Husain
> Research Assistant
> Department of Computer Science
> Erik Jonsson School of Engineering and Computer Science
> University of Texas at Dallas
>
I did it, it does not show anything. Here is what I have got from the config file:
#------------------------------------------------------------------------------
# RESOURCE USAGE (except WAL)
#------------------------------------------------------------------------------
# - Memory -
shared_buffers = 32MB # min 128kB or max_connections*16kB
# (change requires restart)
temp_buffers = 1024MB # min 800kB
#max_prepared_transactions = 5 # can be 0 or more
# (change requires restart)
# Note: Increasing max_prepared_transactions costs ~600 bytes of shared memory
# per transaction slot, plus lock space (see max_locks_per_transaction).
work_mem = 1792MB # min 64kB
#maintenance_work_mem = 16MB # min 1MB
#max_stack_depth = 32MB # min 100kB
# - Free Space Map -
max_fsm_pages = 204800 # min max_fsm_relations*16, 6 bytes each
# (change requires restart)
#max_fsm_relations = 1000 # min 100, ~70 bytes each
# (change requires restart)
# - Kernel Resource Usage -
#max_files_per_process = 1000 # min 25
# (change requires restart)
#shared_preload_libraries = '' # (change requires restart)
# - Cost-Based Vacuum Delay -
#vacuum_cost_delay = 0 # 0-1000 milliseconds
#vacuum_cost_page_hit = 1 # 0-10000 credits
#vacuum_cost_page_miss = 10 # 0-10000 credits
#vacuum_cost_page_dirty = 20 # 0-10000 credits
#vacuum_cost_limit = 200 # 1-10000 credits
# - Background Writer -
#bgwriter_delay = 200ms # 10-10000ms between rounds
#bgwriter_lru_maxpages = 100 # 0-1000 max buffers written/round
#bgwriter_lru_multiplier = 2.0 # 0-10.0 multipler on buffers scanned/round
Please note that this (1792MB) is the highest that I could set for work_mem.
--
Mohammad Farhan Husain
Research Assistant
Department of Computer Science
Erik Jonsson School of Engineering and Computer Science
University of Texas at Dallas
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