From: Jan Wieck <janwieck@Yahoo.com>
Message-Id: <200102071006.FAA02488@jupiter.greatbridge.com>
Subject: Re: Postgres and Oracle differences and questions
In-Reply-To: <3A7BF8A1.57EBABD7@home.com> from "D. Johnson" at "Feb 3,
	2001 06:25:05 am"
To: "D. Johnson" <dspectra@home.com>
Date: Wed, 7 Feb 2001 05:06:11 -0500 (EST)
CC: pgsql-interfaces@postgresql.org
MIME-Version: 1.0
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D. Johnson wrote:
> I have recently been working on several projects that use MSAccess as a
> front end to both a Postgres and Oracle DB. Unfortunately, I have
> noticed some differences and limitations in Oracle that seem to make
> Postgres look like a better choice for the application. My problem is
> with the block sizing differences in PG and Oracle. It seems that when
> mapping memo types from Access to Postgres you could create a text type
> in Postgres that emulates the Access memo type, and you could define a
> table with any number of these types of fields. In Oracle you can only
> have one memo field mapped to a table with a max size equal I believe to
> the block size, and if you use the max block size then you cannot define
> any other fields in the same table.
>
> I am curious how Postgres handles text types, is a var char or does it
> allocate the full 8K for the text type. In Oracle, the size of the table
> definition has to be within the block boundary, is the same restriction
> true in Postgres.

    The  size  limitations (8K by default, 32K max) are gone with
    7.1. Well, you shouldn't  really  use  100+  MB  sized  rows,
    because the resulting INSERT already needs to travel from the
    frontend, through the parser down into the executor.  And  on
    SELECT  the  client  needs  to buffer all the data at once in
    memory.  But if you really need  to  do  it,  swap  space  is
    cheap...


Jan

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