Re: [PERFORM] Heavy contgnous load

2011-10-19 Thread Craig Ringer
On 10/20/2011 02:55 AM, kzsolt wrote: "try to have as few indexes as possible and do your inserts inside transactions in batches, rather than one-by-one as individual statements. " That is the main problem. I use now few index as possible. Unfortunately the one-by-one INSERT is nature of or syste

Re: [PERFORM] How many Cluster database on a single server

2011-10-19 Thread Craig Ringer
On 10/19/2011 05:46 PM, d.davo...@mastertraining.it wrote: My colleagues are asking how many Cluster Databases (initdb) can I create and run on a single server. I mean, supposed my server has the resources, can I create 100 or even 200 Cluster Databases? Yep. It won't be fast, but it'll work.

Re: [PERFORM] delete/recreate indexes

2011-10-19 Thread Jeff Davis
On Wed, 2011-10-19 at 08:03 -0700, alan wrote: > So I thought I’d just run this once (via cron) every morning. > BEGIN; > DROP INDEX data_unique; > UPDATE data SET datum = (data.datum + interval '24 hours'); > CREATE UNIQUE INDEX data_unique ON public.data USING BTREE >

Re: [PERFORM] disused indexes and performance?

2011-10-19 Thread Scott Marlowe
On Wed, Oct 19, 2011 at 9:24 AM, Elisa wrote: > I recently ran a query against our production database and saw several > disused indexes.  Is there a performance harm in having disused > indexes out there? Sure there is, they'll slow down writes and use more disk space. > Of course, I will be ch

Re: [PERFORM] Heavy contgnous load

2011-10-19 Thread kzsolt
Kevin Grittner wrote: > Rollback activity? What rollback activity? When you're doing what? > What is the exact message? I mean here some kind of option to save reources. For example mysql has table (storage) type where no transaction support (rollback) in. This make the all server faster and us

Re: [PERFORM] Heavy contgnous load

2011-10-19 Thread kzsolt
"try to have as few indexes as possible and do your inserts inside transactions in batches, rather than one-by-one as individual statements. " That is the main problem. I use now few index as possible. Unfortunately the one-by-one INSERT is nature of or system. To join (batch) inserts is require sp

[PERFORM] disused indexes and performance?

2011-10-19 Thread Elisa
I recently ran a query against our production database and saw several disused indexes. Is there a performance harm in having disused indexes out there? Of course, I will be checking our code base and with developers to ensure that these indexes aren't being used programmatically to prevent redun

[PERFORM] delete/recreate indexes

2011-10-19 Thread alan
Hi I'm a postgres novice so I have this fairly simple table - device integer not null, group integer not null, datum timestamp without time zone not null, val1 numeric(7,4) not null default 0.000, val2 numeric(7,4) not null default 0.000 -

Re: [PERFORM] does update of column with no relation imply a relation check of other column?

2011-10-19 Thread Greg Jaskiewicz
On 19 Oct 2011, at 17:51, Anibal David Acosta wrote: > For example: > Table A > -id (PK) > -name > > Table B > -table_a_id (PK, FK) > -address > > When I do an insert on table B, the database check if value for column > “table_a_id” exists in table A > But, if I do an update of column “addre

[PERFORM] does update of column with no relation imply a relation check of other column?

2011-10-19 Thread Anibal David Acosta
For example: Table A -id (PK) -name Table B -table_a_id (PK, FK) -address When I do an insert on table B, the database check if value for column "table_a_id" exists in table A But, if I do an update of column "address" of table B, does the database check again? My question is due

Re: [PERFORM] How many Cluster database on a single server

2011-10-19 Thread Scott Marlowe
On Wed, Oct 19, 2011 at 9:02 AM, d.davo...@mastertraining.it wrote: > Hi Craig, > thanks for your reply. I think I need to add some details on my question, > like why we would need more than one Cluster Database. We are thinking to > use the Streaming Replica feature to keep in sync a number of li

Re: [PERFORM] How many Cluster database on a single server

2011-10-19 Thread Kevin Grittner
"d.davo...@mastertraining.it" wrote: > We are thinking to use the Streaming Replica feature to keep in > sync a number of little DB servers around the net. The replica > should happen on one or more centralized servers. I didn't tested > the replica personally bus as I can see, it syncs the whol

Re: [PERFORM] How many Cluster database on a single server

2011-10-19 Thread d.davo...@mastertraining.it
Hi Craig, thanks for your reply. I think I need to add some details on my question, like why we would need more than one Cluster Database. We are thinking to use the Streaming Replica feature to keep in sync a number of little DB servers around the net. The replica should happen on one or more

Re: [PERFORM] Rapidly finding maximal rows

2011-10-19 Thread Merlin Moncure
On Tue, Oct 11, 2011 at 8:05 PM, Dave Crooke wrote: > Hi James > > > I'm guessing the problem is that the combination of using a view and the way > the view is defined with an in-line temporary table is too complex for the > planner to introspect into, transform and figure out the equivalent direc

Re: [PERFORM] How many Cluster database on a single server

2011-10-19 Thread Craig James
On 10/19/11 2:46 AM, d.davo...@mastertraining.it wrote: Hi everybody, I googled a bit around and also checked the mailing lists but I still can't make an idea. We plan to use postgres 9 and the Cluster Database Replica. My colleagues are asking how many Cluster Databases (initdb) can I create an

Re: [PERFORM] Inner Join - Explicit vs Implicit Join Performance

2011-10-19 Thread Pavel Stehule
Hello no, there is no difference - you can check it via EXPLAIN statement Regards Pavel Stehule 2011/10/19 Gnanakumar : > Hi, > > In PostgreSQL, is there any performance difference between queries written > using "explicit join notation" vs "implicit join notation" in complex > queries? > > EXA

[PERFORM] Inner Join - Explicit vs Implicit Join Performance

2011-10-19 Thread Gnanakumar
Hi, In PostgreSQL, is there any performance difference between queries written using "explicit join notation" vs "implicit join notation" in complex queries? EXAMPLE: Simple "explicit join notation" SELECT * FROM employee INNER JOIN department ON employee.DepartmentID = department.Departmen

[PERFORM] How many Cluster database on a single server

2011-10-19 Thread d.davo...@mastertraining.it
Hi everybody, I googled a bit around and also checked the mailing lists but I still can't make an idea. We plan to use postgres 9 and the Cluster Database Replica. My colleagues are asking how many Cluster Databases (initdb) can I create and run on a single server. I mean, supposed my server ha