----- Original Message -----
From: "Sean" <firebird_tmc@...>

|Table ABC with ID, Insert_Time, and some other fields. ID has both
|ascending and descending index, same for Insert_Time.

not a problem but -- I don´t think having both desc and asc indices help on
anything. Since you are ordering desc, having only a desc index should be
enougth.

|The optimizer used the same plan:
|PLAN (ABC ORDER IDX_ID_DESC)

To me it seems hard to believe that. Are you sure the optimizer used this
PLAN for query 3??? couse I think it should use the index on INSERT_TIME.
quite weird.


|I have around 1,7 million records per week, and I need to store up to
|1 year data.

so, by looking at your query 1, it seems to me you're fetching as much as
1,7 million records... is that what you need?


Regards,
Anderson

--- In firebird-support@yahoogroups.com, "Martijn Tonies"
<m.tonies@...> wrote:

> The problem with separate tables is when you have to query across
> multiple tables.
>
> Do you have any indices on your large table? How many rows per week?
>