| Lists: | pgsql-general |
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| From: | Sebastjan Trepca <trepca(at)gmail(dot)com> |
|---|---|
| To: | Postgres General <pgsql-general(at)postgresql(dot)org> |
| Subject: | Time complexity of statements |
| Date: | 2006-02-14 15:13:03 |
| Message-ID: | cd329af80602140713p41d8b5e1sf5f19fd0bccb3f43@mail.gmail.com |
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| Lists: | pgsql-general |
Hi everybody!
As I understood from books and docs every statement in Postgres takes
O(1) because of it's versioning system, right?
I'm talking about INSERT,UPDATE,SELECT and DELETE statement.
Is it true? or did I get it wrong.
I'm specially interested in UPDATE statement. We'll have lots of them.
Thanks, Sebastjan
| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Sebastjan Trepca <trepca(at)gmail(dot)com> |
| Cc: | Postgres General <pgsql-general(at)postgresql(dot)org> |
| Subject: | Re: Time complexity of statements |
| Date: | 2006-02-14 15:29:43 |
| Message-ID: | 15084.1139930983@sss.pgh.pa.us |
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| Lists: | pgsql-general |
Sebastjan Trepca <trepca(at)gmail(dot)com> writes:
> As I understood from books and docs every statement in Postgres takes
> O(1) because of it's versioning system, right?
Finding an existing row is not O(1), so this is not the case for
anything but INSERT. You also have to consider index update costs,
foreign key checking costs if applicable, etc etc.
regards, tom lane
| From: | Peter Eisentraut <peter_e(at)gmx(dot)net> |
|---|---|
| To: | pgsql-general(at)postgresql(dot)org |
| Cc: | Sebastjan Trepca <trepca(at)gmail(dot)com> |
| Subject: | Re: Time complexity of statements |
| Date: | 2006-02-14 15:31:30 |
| Message-ID: | 200602141631.31765.peter_e@gmx.net |
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| Lists: | pgsql-general |
Am Dienstag, 14. Februar 2006 16:13 schrieb Sebastjan Trepca:
> As I understood from books and docs every statement in Postgres takes
> O(1) because of it's versioning system, right?
Absolutely not.
--
Peter Eisentraut
http://developer.postgresql.org/~petere/
| From: | Sebastjan Trepca <trepca(at)gmail(dot)com> |
|---|---|
| To: | Peter Eisentraut <peter_e(at)gmx(dot)net> |
| Cc: | pgsql-general(at)postgresql(dot)org |
| Subject: | Re: Time complexity of statements |
| Date: | 2006-02-14 17:03:23 |
| Message-ID: | cd329af80602140903k2958490dm2c506f678bcd4304@mail.gmail.com |
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| Lists: | pgsql-general |
Ok, thanks. I guess that was a stupid question, sorry :)
I guess we'll have to use INSERTs instead of UPDATEs.
Sebastjan
On 2/14/06, Peter Eisentraut <peter_e(at)gmx(dot)net> wrote:
> Am Dienstag, 14. Februar 2006 16:13 schrieb Sebastjan Trepca:
> > As I understood from books and docs every statement in Postgres takes
> > O(1) because of it's versioning system, right?
>
> Absolutely not.
>
> --
> Peter Eisentraut
> http://developer.postgresql.org/~petere/
>