Slow Executing queries

<FONT face="Courier New">Tom:<BR><BR>We have a IBM NetServer i with 2.5 GB
de Ram and RAID 5 with 137 GB, two<BR>PIV Xeon at 1.6 GHZ... I mounted Linux
in this server with<BR>PostgreSQL 7.3, we start to deploy the database and
we have a lot of<BR>performance problems, i need help for tune up the
server....i read the faqs,<BR>a lots of documents about gets better
performance but i don't obtain good<BR>results...for example this table:
OBLIGACION have 15 millions of records<BR><BR>Column | Type |
Modifiers<BR>----------+-----------------------+-----------<BR>cuil |
numeric(11,0) |<BR>objeto | character varying(11) |<BR>impuesto |
numeric(3,0) |<BR>concepto | numeric(3,0) |<BR>tipobj | numeric(3,0)
|<BR>fecvtop | date |<BR>fecvtod | date |<BR>graba | date |<BR>fecgen | date
|<BR>hora | character varying(4) |<BR>operador | character varying(10)
|<BR>numoble | numeric(13,0) |<BR>puesto | numeric(3,0) |<BR>secsec |
numeric(4,0) |<BR>periodo | numeric(6,0) |<BR>cuota | numeric(3,0)
|<BR>ctrlpago | numeric(3,0) |<BR>ddjjd | numeric(3,0) |<BR>tipopp |
numeric(4,0) |<BR>nroppago | numeric(8,0) |<BR>marca | numeric(3,0)
|<BR>Indexes: numoble_oblig btree (numoble),<BR>objeto_oblig btree
(objeto),<BR>periodo_oblig btree (periodo)<BR><BR>sapym=# explain select
max(numoble) from obligacion where periodo=200100;<BR>QUERY
PLAN<BR>----------------------------------------------------------------------------<BR>-----------------------<BR>Aggregate
(cost=6983070.47..6983070.47 rows=1 width=16)<BR>-&gt; Index Scan using
periodo_oblig on obligacion (cost=0.00..6978186.18<BR>rows=1953717
width=16)<BR>Index Cond: (periodo = 200100::numeric)<BR>(3
rows)<BR><BR>&gt;&gt; there is a index for obligacion on periodo but this
query takes over 2<BR>minutes for finish.<BR><BR><BR>sapym=# explain select
count(*) from obligacion where periodo=200100;<BR>QUERY
PLAN<BR>----------------------------------------------------------------------------<BR>----------------------<BR>Aggregate
(cost=6983070.47..6983070.47 rows=1 width=0)<BR>-&gt; Index Scan using
periodo_oblig on obligacion (cost=0.00..6978186.18<BR>rows=1953717
width=0)<BR>Index Cond: (periodo = 200100::numeric)<BR>(3 rows)<BR><BR>can
you help to solve the problem? i really want to use PostgreSQL in
my<BR>organization but if i can't solve this problem we must<BR>migrate to
ugly DB2 .<BR><BR>thanks in advance.<BR><BR>Gabriel
Monsalvo</FONT><BR><BR><br><br><br><br>
<br>
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