----- Original Message -----
From: "Moti Asayag" <masayag(a)redhat.com>
To: "Eli Mesika" <emesika(a)redhat.com>
Cc: "engine-devel(a)ovirt.org" <devel(a)ovirt.org>
Sent: Wednesday, March 11, 2015 11:53:50 AM
Subject: Re: [ovirt-devel] Important changes in the Search Engine code
----- Original Message -----
> From: "Eli Mesika" <emesika(a)redhat.com>
> To: "engine-devel(a)ovirt.org" <devel(a)ovirt.org>
> Sent: Wednesday, March 11, 2015 10:48:44 AM
> Subject: [ovirt-devel] Important changes in the Search Engine code
>
> Hi All
>
> We had in the past many cases in which the search engine returned duplicate
> records.
> Most of those cases are not simple to resolve in the DB layer by changing
> the
> query due to schema limitations.
> We had decided to handle that by adding DISTINCT to the queries that the
> search engine generates [1]
Wouldn't that cause some penalty for each query ? Each navigation between
tabs in
the UI will become slower now that the returned values need to be sorted,
even when
not required ?
We had tested that for a while and the penalty is relatively small.
We surely can come with a better solution but it requires heavy schema changes
I think we can live with that ....
> However, we might have cases in which both DISTINCT and ORDER BY f({args})
> (where f is a function call) is used
> In that case, we will get SQL exception since the ORDER BY is applied on
> the
> DISTINCT result that does not include f as a field.
> I had prevented using DISTINCT in such cases [2]
> That means that you still may got duplicates in such cases and then you
> should handle it in the same method as in [3]
> (basically returning the function result in the select as a computed field)
>
>
> [1]
https://gerrit.ovirt.org/#/c/31896
> [2]
https://gerrit.ovirt.org/#/c/38459
> [3]
https://gerrit.ovirt.org/#/c/36946
>
>
> Thanks
> Eli Mesika
>
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