Thread: Re: Oracle and Postgresql Play Nice Together on Same Computer?
Troyston Campano <troygeekdatabase@gmail.com> wrote on 20.01.2005, 06:03:28: > I am an Oracle DBA and I want do a Postgresql 'proof of concept' at the > large corporation where I work to test the benefits of using Postgresql in > our environment. I want to install Postgresql onto a "production" server > that currently runs Oracle. Are there any problems with running Postgresql > and Oracle on the same machine? I mean, I've heard that the way Sybase and > DB2 UDB are architected to handle memory hurts Sybase when DB2 UDB is > installed on the same machine as the Sybase Server (something about UDB > eating up all the memory and not giving it back to Sybase). > > > > Are there any issues running Postgresql and Oracle on the same > machine.anything special to know about memory, disk layout, and things like > that? I just want to make sure the two engines play together on this same > server. I had a hard time finding information about this via google. > There should be no issues running both on the same machine. Running both together at the same time isn't a good way of doing a benchmark though... I would question your intent slightly. Should it be a relative comparison? Or should it be an assessment of what PostgreSQL is capable of and whether that fits a sufficient number of your needs to make it worth adopting? There are many ways to structure a decision as to whether PostgreSQL is suitable for your (business?) needs. Which structure you choose is likely to prejudice your decision, one way or the other. i.e. if capital acquisition costs are the decising factor, then PostgreSQL would always win. Best Regards, Simon Riggs
On Thu, 20 Jan 2005 simon@2ndquadrant.com wrote:
>
> Troyston Campano <troygeekdatabase@gmail.com> wrote on 20.01.2005,
> 06:03:28:
>> I am an Oracle DBA and I want do a Postgresql 'proof of concept' at the
>> large corporation where I work to test the benefits of using Postgresql in
>> our environment. I want to install Postgresql onto a "production" server
>> that currently runs Oracle. Are there any problems with running Postgresql
>> and Oracle on the same machine? I mean, I've heard that the way Sybase and
>> DB2 UDB are architected to handle memory hurts Sybase when DB2 UDB is
>> installed on the same machine as the Sybase Server (something about UDB
>> eating up all the memory and not giving it back to Sybase).
>>
>>
>>
>> Are there any issues running Postgresql and Oracle on the same
>> machine.anything special to know about memory, disk layout, and things like
>> that? I just want to make sure the two engines play together on this same
>> server. I had a hard time finding information about this via google.
>>
>
> There should be no issues running both on the same machine. Running both
> together at the same time isn't a good way of doing a benchmark
> though...
>
> I would question your intent slightly. Should it be a relative
> comparison? Or should it be an assessment of what PostgreSQL is capable
> of and whether that fits a sufficient number of your needs to make it
> worth adopting?
>
> There are many ways to structure a decision as to whether PostgreSQL is
> suitable for your (business?) needs. Which structure you choose is
> likely to prejudice your decision, one way or the other. i.e. if
> capital acquisition costs are the decising factor, then PostgreSQL
> would always win.
I may add that using the right tool for the right task should be
a priority. It's easy to underestimate the cost of continuosly
adapting your needs to the tool and not the opposite.
About Oracle I keep hearing success or horror stories. About PostgreSQL
mostly success stories, some unsuccess stories ("it's good but we switched
back to MS SQL" ), _very_ few horror stories. Last horror story was
about "data worth having but not backupping", a category existing only
in some manager's mind (and _deserving_ a horror story).
Note that I've never heard any unsuccess story about Oracle. I know
some people that would tell one, if only they actually tried PostgreSQL
out - but that's my opinion, not thiers (yet).
IMHO, migrating from Oracle to PostgreSQL usually doesn't expose
all PostgreSQL pros, and will expose some weaknesses or missing features.
Migrating from PostgreSQL to Oracle is what really makes PostgreSQL shine.
Too bad it happens so rarely. :-)
.TM.
--
____/ ____/ /
/ / / Marco Colombo
___/ ___ / / Technical Manager
/ / / ESI s.r.l.
_____/ _____/ _/ Colombo@ESI.it
Re: [ADMIN] Oracle and Postgresql Play Nice Together on Same Computer?
From
"Troyston Campano"
Date:
Basically, we want to take 3 of the 10 applications running on Oracle, move them to Postgresql on the same computer/server and just make sure it runs about the same (really speed, memory usage, and space are the big issues). I'm not concerned with how hard the migration will be and things like that. The database is very low in complexity so the migration should be cake. Thank you! -----Original Message----- From: simon@2ndquadrant.com [mailto:simon@2ndquadrant.com] Sent: Thursday, January 20, 2005 4:20 AM To: Troyston Campano Cc: pgsql-admin@postgresql.org; pgsql-general@postgresql.org Subject: Re: [ADMIN] Oracle and Postgresql Play Nice Together on Same Computer? Troyston Campano <troygeekdatabase@gmail.com> wrote on 20.01.2005, 06:03:28: > I am an Oracle DBA and I want do a Postgresql 'proof of concept' at the > large corporation where I work to test the benefits of using Postgresql in > our environment. I want to install Postgresql onto a "production" server > that currently runs Oracle. Are there any problems with running Postgresql > and Oracle on the same machine? I mean, I've heard that the way Sybase and > DB2 UDB are architected to handle memory hurts Sybase when DB2 UDB is > installed on the same machine as the Sybase Server (something about UDB > eating up all the memory and not giving it back to Sybase). > > > > Are there any issues running Postgresql and Oracle on the same > machine.anything special to know about memory, disk layout, and things like > that? I just want to make sure the two engines play together on this same > server. I had a hard time finding information about this via google. > There should be no issues running both on the same machine. Running both together at the same time isn't a good way of doing a benchmark though... I would question your intent slightly. Should it be a relative comparison? Or should it be an assessment of what PostgreSQL is capable of and whether that fits a sufficient number of your needs to make it worth adopting? There are many ways to structure a decision as to whether PostgreSQL is suitable for your (business?) needs. Which structure you choose is likely to prejudice your decision, one way or the other. i.e. if capital acquisition costs are the decising factor, then PostgreSQL would always win. Best Regards, Simon Riggs
On Thu, Jan 20, 2005 at 08:03:42AM -0500, Troyston Campano wrote: > Basically, we want to take 3 of the 10 applications running on Oracle, move > them to Postgresql on the same computer/server and just make sure it runs > about the same (really speed, memory usage, and space are the big issues). > I'm not concerned with how hard the migration will be and things like that. So you want Postgres to be a cheaper Oracle. Hmm. Maybe it will work, but as Marco Colombo says, you are not going to see Postgres shining by using that simplistic approach. If you want that, maybe you should look closely to see where you can find the rusty corner that needs to be polished. > The database is very low in complexity so the migration should be cake. If you do things as simple as "select count(*) from table", then you will have to be careful to be really fair in your comparison; you could misleadingly find that Postgres is much slower on that query. -- Alvaro Herrera (<alvherre[@]dcc.uchile.cl>) Tulio: oh, para qué servirá este boton, Juan Carlos? Policarpo: No, aléjense, no toquen la consola! Juan Carlos: Lo apretaré una y otra vez.
[ Cc: list cleaned a bit ]
On Thu, 20 Jan 2005, Alvaro Herrera wrote:
> On Thu, Jan 20, 2005 at 08:03:42AM -0500, Troyston Campano wrote:
>> Basically, we want to take 3 of the 10 applications running on Oracle, move
>> them to Postgresql on the same computer/server and just make sure it runs
>> about the same (really speed, memory usage, and space are the big issues).
>> I'm not concerned with how hard the migration will be and things like that.
>
> So you want Postgres to be a cheaper Oracle. Hmm. Maybe it will work,
> but as Marco Colombo says, you are not going to see Postgres shining by
> using that simplistic approach. If you want that, maybe you should look
> closely to see where you can find the rusty corner that needs to be
> polished.
>
>> The database is very low in complexity so the migration should be cake.
>
> If you do things as simple as "select count(*) from table", then you
> will have to be careful to be really fair in your comparison; you could
> misleadingly find that Postgres is much slower on that query.
Yeah, that's precisely what I meant. The Oracle to PostgreSQL migration
is well worth considering a (partial) redesign.
Sometimes I happen to show some SQL queries I make (on PostgreSQL)
to an Oracle guy. Usually it goes like this:
1) hmm (ponders at the query)
2) ah!!! (realizes what the query does)
3) I didn't know you could do this! (excitement)
4) hmm (ponders again if that may work on Oracle as well)
5) no I can't do that in Oracle that way. I remember I did something
like that in the past with other 3 SQL developers. We had to write
a 300 lines long stored procedure, we got the locking right at the
third reimplementation only (we don't know if we do need the locking,
we asked our senior DBA but he was unsure as well, so we put it in,
we don't think it hurts anyway).
Ok, point 5) has been exaggerated to joke level, but you get the idea.
.TM.
--
____/ ____/ /
/ / / Marco Colombo
___/ ___ / / Technical Manager
/ / / ESI s.r.l.
_____/ _____/ _/ Colombo@ESI.it
I'm not really too concerned about the migration aspect at all. If need be, we might even throw in some new applications into the postgresql database. What we're really concerned about is any issues that may come from running postgresql and oracle on the same box. Do they play nice together...or does one hog memory in a way that prevents the other engine from operating correctly? I'm worried more about things like that. thank you again for your time! ~ Troyston ~ On Thu, 20 Jan 2005 15:22:33 +0100 (CET), Marco Colombo <pgsql@esiway.net> wrote: > [ Cc: list cleaned a bit ] > > On Thu, 20 Jan 2005, Alvaro Herrera wrote: > > > On Thu, Jan 20, 2005 at 08:03:42AM -0500, Troyston Campano wrote: > >> Basically, we want to take 3 of the 10 applications running on Oracle, move > >> them to Postgresql on the same computer/server and just make sure it runs > >> about the same (really speed, memory usage, and space are the big issues). > >> I'm not concerned with how hard the migration will be and things like that. > > > > So you want Postgres to be a cheaper Oracle. Hmm. Maybe it will work, > > but as Marco Colombo says, you are not going to see Postgres shining by > > using that simplistic approach. If you want that, maybe you should look > > closely to see where you can find the rusty corner that needs to be > > polished. > > > >> The database is very low in complexity so the migration should be cake. > > > > If you do things as simple as "select count(*) from table", then you > > will have to be careful to be really fair in your comparison; you could > > misleadingly find that Postgres is much slower on that query. > > Yeah, that's precisely what I meant. The Oracle to PostgreSQL migration > is well worth considering a (partial) redesign. > > Sometimes I happen to show some SQL queries I make (on PostgreSQL) > to an Oracle guy. Usually it goes like this: > > 1) hmm (ponders at the query) > 2) ah!!! (realizes what the query does) > 3) I didn't know you could do this! (excitement) > 4) hmm (ponders again if that may work on Oracle as well) > 5) no I can't do that in Oracle that way. I remember I did something > like that in the past with other 3 SQL developers. We had to write > a 300 lines long stored procedure, we got the locking right at the > third reimplementation only (we don't know if we do need the locking, > we asked our senior DBA but he was unsure as well, so we put it in, > we don't think it hurts anyway). > > Ok, point 5) has been exaggerated to joke level, but you get the idea. > > .TM. > -- > ____/ ____/ / > / / / Marco Colombo > ___/ ___ / / Technical Manager > / / / ESI s.r.l. > _____/ _____/ _/ Colombo@ESI.it > > ---------------------------(end of broadcast)--------------------------- > TIP 6: Have you searched our list archives? > > http://archives.postgresql.org >
Re: [ADMIN] Oracle and Postgresql Play Nice Together on Same Computer?
From
"Frank D. Engel, Jr."
Date:
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Does anyone know if there could be a shared memory issue here? If there is, then one of the two (postgres or oracle) would simply refuse to start (it would quit with an error, I'd assume). If this happens, you would need to either decrease the number of shared memory resources one database or the other is asking for, or increase the number of shared memory resources made available by the kernel (the exact process depends on your operating system; I forget if you named the one you are using or not). Otherwise, there shouldn't be a problem, as long as your server hardware has the resources to handle both at the same time (disk space, memory/CPU power, etc.) On Jan 20, 2005, at 10:50 AM, troyston campano wrote: > I'm not really too concerned about the migration aspect at all. If > need be, we might even throw in some new applications into the > postgresql database. What we're really concerned about is any issues > that may come from running postgresql and oracle on the same box. Do > they play nice together...or does one hog memory in a way that > prevents the other engine from operating correctly? I'm worried more > about things like that. > > thank you again for your time! > > ~ Troyston ~ > > > On Thu, 20 Jan 2005 15:22:33 +0100 (CET), Marco Colombo > <pgsql@esiway.net> wrote: >> [ Cc: list cleaned a bit ] >> >> On Thu, 20 Jan 2005, Alvaro Herrera wrote: >> >>> On Thu, Jan 20, 2005 at 08:03:42AM -0500, Troyston Campano wrote: >>>> Basically, we want to take 3 of the 10 applications running on >>>> Oracle, move >>>> them to Postgresql on the same computer/server and just make sure >>>> it runs >>>> about the same (really speed, memory usage, and space are the big >>>> issues). >>>> I'm not concerned with how hard the migration will be and things >>>> like that. >>> >>> So you want Postgres to be a cheaper Oracle. Hmm. Maybe it will >>> work, >>> but as Marco Colombo says, you are not going to see Postgres shining >>> by >>> using that simplistic approach. If you want that, maybe you should >>> look >>> closely to see where you can find the rusty corner that needs to be >>> polished. >>> >>>> The database is very low in complexity so the migration should be >>>> cake. >>> >>> If you do things as simple as "select count(*) from table", then you >>> will have to be careful to be really fair in your comparison; you >>> could >>> misleadingly find that Postgres is much slower on that query. >> >> Yeah, that's precisely what I meant. The Oracle to PostgreSQL >> migration >> is well worth considering a (partial) redesign. >> >> Sometimes I happen to show some SQL queries I make (on PostgreSQL) >> to an Oracle guy. Usually it goes like this: >> >> 1) hmm (ponders at the query) >> 2) ah!!! (realizes what the query does) >> 3) I didn't know you could do this! (excitement) >> 4) hmm (ponders again if that may work on Oracle as well) >> 5) no I can't do that in Oracle that way. I remember I did something >> like that in the past with other 3 SQL developers. We had to write >> a 300 lines long stored procedure, we got the locking right at the >> third reimplementation only (we don't know if we do need the >> locking, >> we asked our senior DBA but he was unsure as well, so we put it in, >> we don't think it hurts anyway). >> >> Ok, point 5) has been exaggerated to joke level, but you get the idea. >> >> .TM. >> -- >> ____/ ____/ / >> / / / Marco Colombo >> ___/ ___ / / Technical Manager >> / / / ESI s.r.l. >> _____/ _____/ _/ Colombo@ESI.it >> >> ---------------------------(end of >> broadcast)--------------------------- >> TIP 6: Have you searched our list archives? >> >> http://archives.postgresql.org >> > > ---------------------------(end of > broadcast)--------------------------- > TIP 5: Have you checked our extensive FAQ? > > http://www.postgresql.org/docs/faqs/FAQ.html > > - ----------------------------------------------------------- Frank D. Engel, Jr. <fde101@fjrhome.net> $ ln -s /usr/share/kjvbible /usr/manual $ true | cat /usr/manual | grep "John 3:16" John 3:16 For God so loved the world, that he gave his only begotten Son, that whosoever believeth in him should not perish, but have everlasting life. $ -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.4 (Darwin) iD8DBQFB79ef7aqtWrR9cZoRAvdMAJwKW+dptxX+zPv5Ql1XUbzPDZGvywCaAqpN ghnwgW9m1Qtcb/QBqWzpGf0= =d65G -----END PGP SIGNATURE----- ___________________________________________________________ $0 Web Hosting with up to 120MB web space, 1000 MB Transfer 10 Personalized POP and Web E-mail Accounts, and much more. Signup at www.doteasy.com
It depends how you have your Oracle instance configured. If you have it set up so that the total SGA and UGA ammount consume around 80%-90% of total available memory, then this is obviously only going to leave postgress with 20% or less of the total available memory. Postgres is also designed to take advantage of the file caching behaviour of the OS. The OS however is probably going to prioritize Oracle running memory over cached file pages, and therefore I would think that running the two together is a less than optimal configuration. If you are going to do it, I would make sure that you at least reduce the SGA for Oracle down below 40% of the box's total RAM so you give postgresql enough space to work in. Even doing this, there is a chance that the OS will try to cache the Oracle Tablespace files if they are small enough, duplicating the buffering effort that Oracle is doing, and also reducing the amount of memory for Postgresql file cache. All in all, I would personaly be very wary of running both together if you are planning on doing any benchmarking. Alex Turner NetEconomist On Thu, 20 Jan 2005 10:20:02 +0100, simon@2ndquadrant.com <simon@2ndquadrant.com> wrote: > > Troyston Campano <troygeekdatabase@gmail.com> wrote on 20.01.2005, > 06:03:28: > > I am an Oracle DBA and I want do a Postgresql 'proof of concept' at the > > large corporation where I work to test the benefits of using Postgresql in > > our environment. I want to install Postgresql onto a "production" server > > that currently runs Oracle. Are there any problems with running Postgresql > > and Oracle on the same machine? I mean, I've heard that the way Sybase and > > DB2 UDB are architected to handle memory hurts Sybase when DB2 UDB is > > installed on the same machine as the Sybase Server (something about UDB > > eating up all the memory and not giving it back to Sybase). > > > > > > > > Are there any issues running Postgresql and Oracle on the same > > machine.anything special to know about memory, disk layout, and things like > > that? I just want to make sure the two engines play together on this same > > server. I had a hard time finding information about this via google. > > > > There should be no issues running both on the same machine. Running both > together at the same time isn't a good way of doing a benchmark > though... > > I would question your intent slightly. Should it be a relative > comparison? Or should it be an assessment of what PostgreSQL is capable > of and whether that fits a sufficient number of your needs to make it > worth adopting? > > There are many ways to structure a decision as to whether PostgreSQL is > suitable for your (business?) needs. Which structure you choose is > likely to prejudice your decision, one way or the other. i.e. if > capital acquisition costs are the decising factor, then PostgreSQL > would always win. > > Best Regards, Simon Riggs > > ---------------------------(end of broadcast)--------------------------- > TIP 8: explain analyze is your friend >