Re: postgresql performance with multimedia

Not sure about the overall performance, etc. but I think that in order to collect statistics you need to set some values in the postgresql.conf config file, to wit:
#---------------------------------------------------------------------------
# RUNTIME STATISTICS
#---------------------------------------------------------------------------

# - Statistics Monitoring -

#log_parser_stats = false
#log_planner_stats = false
#log_executor_stats = false
#log_statement_stats = false

# - Query/Index Statistics Collector -

stats_start_collector = true
stats_command_string = true
stats_block_level = true
stats_row_level = true
#stats_reset_on_server_start = true

If the appropriate values aren't set this could account for why no entries are found in the pg_stat tables. The manual has details on these; you'll need to reload postgres to make any changes effective.

Greg

-----Original Message-----
From: my ho [mailto:mthoatbanjo(at)yahoo(dot)com]
Sent: Tue 8/24/2004 11:54 PM
To: pgsql-performance(at)postgresql(dot)org
Cc: Jan Wieck
Subject: Re: [PERFORM] postgresql performance with multimedia
> Tom Lane answered to that question. The code in
> question does resolve
> "localhost" with getaddrinfo() and then tries to
> create and bind a UDP
> socket to all returned addresses. For some reason
> "localhost" on your
> system resolves to an address that is not available
> for bind(2).

I tried to put my_ip instead of "localhost" in
bufmng.c and it seems to work (no more complaining).
However i check the pg_statio_all_tables and dont see
any recorded statistic at all. (all the columns are
'0')
some time postmaster shut down with this err msg:
LOG: statistics collector process (<process_id>)
exited with exit code 1
i starts postmaster with this command:
postmaster -i -p $PORT -D $PGDATA -k $PGDATA -N 32 -B
64 -o -s

> > btw, what i want to ask here is does postgreSQL
> have
> > any kind of read-ahead buffer implemented? 'cos it
> > would be useful in multimedia case when we always
> scan
> > the large table for continous data.
>
> Since there is no mechanism to control that data is
> stored contiguously
> in the tables, what would that be good for?

i thought that rows in the table will be stored
contiguously? in that case, if the user is requesting
1 row, we make sure that the continue rows are ready
in the buffer pool so that when they next requested,
they wont be asked to read from disk. For multimedia
data, this is important 'cos data needs to be
presented continuously without any waiting.

thanks again for your help
MT Ho

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