Re: [Firebird-devel] "Covering" index?

[Ann H. <an...@qb...>]

On Mon, Jan 28, 2013 at 11:42 AM, Dimitry Sibiryakov <sd...@ib...>wrote:

> 28.01.2013 17:27, Thomas Steinmaurer wrote:
> > How does the engine know when to garbage collect an index
> > entry?
>
>    When list of record references in it is empty.
>
> -

Expanding again, when Firebird garbage collects a record version, it checks
keys for all the indexes on the record, building a list of "staying and
going"  values  - values that are, or are not, duplicated in other versions
of the same record.  It then removes the index entries for the "going"
values.

Cheers,

Ann