From: ashah <ashah@opuspro.com>
Organization: opus
To: pgsql-performance@postgresql.org
Subject: Re: Massive Inserts Strategies
Date: Tue, 28 Mar 2006 10:59:49 -0500
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	<20060322160924.GJ15742@pervasive.com>
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I tried this solution, but ran into following problem.

The temp_table has columns (col1, col2, col3).

The original_table has columns (col0, col1, col2, col3)

Now the extra col0 on the original_table is the unique generated ID by the 
database.

How can I make your suggestions work in that case .. ?

On Wednesday 22 March 2006 11:09 am, Jim C. Nasby wrote:
> Load the files into a temp table and go from there...
>
> COPY ... FROM file;
> UPDATE existing_table SET ... WHERE ...;
> INSERT INTO existing_table SELECT * FROM temp_table WHERE NOT EXISTS(
> SELECT * FROM existing_table WHERE ...)
>
> On Wed, Mar 22, 2006 at 10:32:10AM -0500, ashah wrote:
> > I have a database with foreign keys enabled on the schema. I receive
> > different files, some of them are huge. And I need to load these files in
> > the database every night. There are several scenerios that I want to
> > design an optimal solution for -
> >
> > 1. One of the file has around 80K records and I have to delete everything
> > from the table and load this file. The provider never provides a "delta
> > file" so I dont have a way to identify which records are already present
> > and which are new. If I dont delete everything and insert fresh, I have
> > to make around 80K selects to decide if the records exist or not. Now
> > there are lot of tables that have foreign keys linked with this table so
> > unless I disable the foreign keys, I cannot really delete anything from
> > this table. What would be a good practise here?
> >
> > 2. Another file that I receive has around 150K records that I need to
> > load in the database. Now one of the fields is logically a "foreign key"
> > to another table, and it is linked to the parent table via a database
> > generated unique ID instead of the actual value. But the file comes with
> > the actual value. So once again, I have to either drop the foreign key,
> > or make 150K selects to determine the serial ID so that the foreign key
> > is satisfied. What would be a good strategy in this scenerio ?
> >
> > Please pardon my inexperience with database !
> >
> > Thanks,
> > Amit
> >
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