Re: [HACKERS] Arbitrary tuple size - Mailing list pgsql-hackers

From Philip Warner
Subject Re: [HACKERS] Arbitrary tuple size
Date
Msg-id 3.0.5.32.19990709115857.00a2ac60@mail.rhyme.com.au
Whole thread Raw
In response to Re: [HACKERS] Arbitrary tuple size  (Tatsuo Ishii <t-ishii@sra.co.jp>)
List pgsql-hackers
At 10:12 9/07/99 +0900, Tatsuo Ishii wrote:
>
>o create a new data type that represents the LO
>



>o when defining the LO data type in a table, it actually points to a
>LO "body" in another place where it is physically stored.

Much as the purist in me hates concept of hard links (as in Leon's suggestions), this *may* be a good application for
them.Certainly that's how Dec(Oracle)/Rdb does it. Since most blobs will be totally rewritten when they are updated,
thisrepresents a slightly smaller problem in terms of MVCC.
 

>o we can have several tables for the LO bodies. Probably a LO body
>table for each corresponding table (where LO data type is defined) is
>appropreate. 

Did you mean a table for each field? Or a table for each table (which may have more than 1 LO field). See comments
below.

>o it would be nice to place a LO table on a separate
>directory/partition from the original table where LO data type is
>defined, since a LO body table could become huge.

I would very much like to see the ability to have multi-file databases and tables - ie. the ability to store and table
orindex in a separate file. Perhaps with a user-defined partitioning function for table rows. The idea being that:
 

1. User specifies that a table can be stored in one of (say) three files.
2. When a record is first stored, the partitioning function is called to determine the file 'storage area' to use. [or
arandom selection method is used]
 

If you are going to allow LOs to be stored in multiple files, it seems a pity not to add some or all of this feature.


Additionally, the issue of pg_dump support for LOs needs to be addressed.


That's sbout it for me,

Philip Warner.

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