Re(2): Re(2): db server is too slow, real slow

sszabo(at)megazone23(dot)bigpanda(dot)com writes:
>On Fri, 20 Oct 2000, pgsql-admin wrote:
>
>> The postgres server was started with the command:
>> /usr/bin/postmaster -i -S -D/var/lib/pgsql
>
>Have you tried changing the values of -B to see if increasing the
>number of buffers helps?

tried it already. i start postmaster with -B 512.
buffer really helps, thanks.

however i got one problem (see below)... but when i started the psql
monitor again,
it did not appear. i'm worried that it would happen again.

applieddata=> SELECT COUNT(*) FROM office, office_application
applieddata-> WHERE office.code = office_application.office_code
applieddata-> AND office_application.active
applieddata-> AND NOT office.deleted;
NOTICE: Message from PostgreSQL backend:
The Postmaster has informed me that some other backend died
abnormally and possibl
y corrupted shared memory.
I have rolled back the current transaction and am going to
terminate your database
system connection and exit.
Please reconnect to the database system and repeat your query.
pqFlush() -- backend closed the channel unexpectedly.
This probably means the backend terminated abnormally before or
while processing t
he request.

>
>> Here is just one query executed from Embperl pages with Perl DBI:
>> officedata=> explain SELECT * FROM office, office_application
>> officedata-> WHERE office.code = office_application.office_code
>> officedata-> AND office_application.active
>> officedata-> AND NOT office.deleted;
>> NOTICE: QUERY PLAN:
>>
>> Hash Join (cost=5524.86 rows=644 width=262)
>> -> Seq Scan on office_application (cost=4261.49 rows=9767 width=245)
>> -> Hash (cost=908.88 rows=854 width=17)
>> -> Seq Scan on office (cost=908.88 rows=854 width=17)
>>
>> note: office.code and office_application.office_code are serial data
>types.
>> office_application.active and office.deleted are boolean.
>> others are char, inet, oid (for lobj), and date data types.
>
>How many rows does the query actually give you,
applieddata=> SELECT COUNT(*) FROM office, office_application
applieddata-> WHERE office.code = office_application.office_code
applieddata-> AND office_application.active
applieddata-> AND NOT office.deleted;
count
-----
12534

>and how many rows in office_application have active true
applieddata=> SELECT COUNT(*) FROM office_application
applieddata-> WHERE office_application.active;
count
-----
12973

>and how many rows in office have deleted false?
applieddata=> SELECT COUNT(*) FROM office
applieddata-> WHERE NOT office.deleted;
count
-----
12534

>
>