[Pljava-dev] Function returning array of rows
Bendik Rognlien Johansen
bensmailinglists at gmail.com
Wed Sep 13 11:09:14 UTC 2006
Hello, I have the following tables (simplified):
records (~8 million rows)
- id integer
- name varchar
addresses (~9 million rows)
- id integer
- record integer
- address varchar
- postalcode varchar
- postalsite varchar
contacts (~12 million rows)
- id integer
- record integer
- value varchar
- type integer
I need to fetch everything to build a Lucene index. My options as I
see it:
1: Join records, addresses and contacts, sort by record.id. Given a
record with 2 addresses and 3 contacts, the result would look
something like this:
name address contact
John Doe Elm street 555-123456
John Doe P.O Box 123 555-123456
John Doe Elm street 555-997788
John Doe P.O Box 123 555-997788
John Doe Elm street 555-666666
John Doe P.O Box 123 555-666666
This is sloow due to sorting, and a lot of redundant data is fetched.
No good
2. Same as 1 but GROUP by record.id, using a custom aggregate
function to create an array of addresses and contacts.
Too slow and error prone.
3. I was hoping to find a way of doing something like this:
SELECT r.*
, MY_NEW_FUNCTION(SELECT * FROM addresses a WHERE a.record = r.id) AS
addresses
, MY_NEW_FUNCTION(SELECT * FROM contacts c WHERE c.record = r.id) AS
contacts
FROM records r;
Where "MY_NEW_FUNCTION" would return an array of the user defined
type "Address" or "Contact".
I have found subselects to perform very well. Does this look
reasonable, or am I being silly?
Any tips on writing the "MY_NEW_FUNCTION"?
Thanks!
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