Re: Re: [SQL] oracle rownum equivalent? - Mailing list pgsql-general

From Tom Lane
Subject Re: Re: [SQL] oracle rownum equivalent?
Date
Msg-id 15872.960475094@sss.pgh.pa.us
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In response to Re: Re: [SQL] oracle rownum equivalent?  ("Cary O'Brien" <cobrien@Radix.Net>)
List pgsql-general
"Cary O'Brien" <cobrien@Radix.Net> writes:
> What I meant to say, and failed, was that in Oracle, rowid
> "psuedo-column" are hex encoded strings containing the block, row, and
> file where the tuple is stored.  So lookup on unindexed rowid *should*
> be fast, although this is not spelled out in my ancient Oracle book.

Oh, in that case it's pretty much like our CTID column.  For example:

regression=# select ctid,* from int8_tbl where ctid = '(0,3)';
 ctid  |        q1        | q2
-------+------------------+-----
 (0,3) | 4567890123456789 | 123
(1 row)

There is some code in 7.0 that tries to implement this in a fast way,
but I don't know how well it works...

            regards, tom lane

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