Re: How to get index columns/dir/ord informations?

Hi!

The pg_index, and pg_indexes is good for I get the index names, and types.

I have two indexes on test table "a":

CREATE INDEX ix1
ON a
USING btree
(a);

CREATE UNIQUE INDEX x2
ON a
USING btree
(a DESC, b);

From this I can recognize the type (unique or normal) of the index, but
none of the columns.

I don't found any tables that can say to me, which columns with which
direction used in index.

A pseudo code demonstrate it:

select * from pg_index_columns where index_name = 'x2'

Ordinal ColName IsAsc
1 a False
2 b True

Have PGSQL same information?

Thanks:
dd

2011.04.01. 18:01 keltezéssel, Raghavendra írta:
> Hi,
>
> Query to list the tables and its concerned indexes.
>
> SELECT indexrelid::regclass as index , relid::regclass as
> table FROM pg_stat_user_indexes JOIN pg_index USING
> (indexrelid) WHERE idx_scan < 100 AND indisunique IS FALSE;
>
> Query will list the contraints.
>
> SELECT relname FROM pg_class WHERE oid IN ( SELECT indexrelid FROM
> pg_index, pg_class WHERE pg_class.oid=pg_index.indrelid AND (
> indisunique = 't' OR indisprimary = 't' ) );
>
> To get the column order number, use this query.
>
> SELECT a.attname,a.attnum FROM pg_class c, pg_attribute a, pg_type t
> WHERE c.relname = 'vacc' AND a.attnum > 0 AND a.attrelid = c.oid AND
> a.atttypid = t.oid;
>
> Note: This query for a particular Table 'VACC'
>
>
> Best Regards,
> Raghavendra
> EnterpriseDB Corporation
>
> On Fri, Apr 1, 2011 at 8:54 PM, Durumdara <durumdara(at)gmail(dot)com
> <mailto:durumdara(at)gmail(dot)com>> wrote:
>
> Hi!
>
> I want to migrate some database to PG.
> I want to make intelligens migrator, that makes the list of the
> SQL-s what need to do to get same table structure in PG as in the
> Source DB.
>
> All things I can get from the views about tables, except the indices.
>
> These indices are not containing the constraints - these elements
> I can analyze.
>
> I found and SQL that get the index columns:
>
>
> select
> t.relname as table_name,
> i.relname as index_name,
> a.attname as column_name
> from
> pg_class t,
> pg_class i,
> pg_index ix,
> pg_attribute a
> where
> t.oid = ix.indrelid
> and i.oid = ix.indexrelid
> and a.attrelid = t.oid
> and a.attnum = ANY(ix.indkey)
> and t.relkind = 'r'
> and t.relname = 'a'
> and ix.indisunique = 'f'
> and ix.indisprimary = 'f'
> order by
> t.relname,
> i.relname;
>
> This can list the columns. But - what a pity - this don't
> containing that:
> - Is this index unique?
> - What the direction of the sort by columns
> - What is the ordinal number of the column
>
> So everything what I need to analyze that the needed index is
> exists or not.
>
>
> Please help me: how can I get these informations?
> I don't want to drop the tables everytime if possible.
>
> Thanks:
> dd
>
>