I don't think this is possible...
you could try a explain on the create
index command but... this is like playinng lotto, didn't try it and
don't have the time to try it;-)
i think getting the size is only possible after creating the index,
because when the index is created it will gather the information about
the data indexed.
if this answer is not enough: why do you need to know the size of the
index BEFORE creating it?
jose fuenmayor wrote:
Ok I understand but I need to know the size of the index before i create it
I need to know how much space it will ocupy (before actually create
the index, having the information of the table on wich I will build
the index), is this possible?
thanks in advance to everyone that can help me.
On 8/23/05, Aldor <an@xxxxxxxxxxxx> wrote:
select * from pg_class;
or
select relname, relpages from pg_class where relname = '[index-name]';
the pages give you the information about the space the index uses, a
page has 8kb.
[...]Every table and index is stored as an array of pages of a fixed
size (usually 8Kb, although a different page size can be selected when
compiling the server). In a table, all the pages are logically
equivalent, so a particular item (row) can be stored in any page. In
indexes, the first page is generally reserved as a metapage holding
control information, and there may be different types of pages within
the index, depending on the index access method. [...]
Source-URL:
http://www.postgresql.org/docs/8.0/interactive/storage-page-layout.html
jose fuenmayor wrote:
---------- Forwarded message ----------
From: jose fuenmayor <jafn82@xxxxxxxxx>
Date: Aug 22, 2005 1:37 PM
Subject: Indexes (Disk space)
To: pgsql-admin@xxxxxxxxxxxxxx
Hi all,
I have the following question.
Is there anyway for me to know how much space on disk will ocupy an
index, created in a determined row or rows of a table?, anything like
a rule, formula, calculation? that allow me to know in advance how
much space will the index use before actually created it.
I aprecciate all the help you can give me
Thanks in advance.
---------------------------(end of broadcast)---------------------------
TIP 1: if posting/reading through Usenet, please send an appropriate
subscribe-nomail command to majordomo@xxxxxxxxxxxxxx so that your
message can get through to the mailing list cleanly
