Re: mysql_fdw trouble

On 10/30/2015 08:13 AM, Dane Foster wrote:
>
> On Fri, Oct 30, 2015 at 10:57 AM, Adrian Klaver
> <adrian(dot)klaver(at)aklaver(dot)com <mailto:adrian(dot)klaver(at)aklaver(dot)com>> wrote:
>
> On 10/30/2015 07:21 AM, Dane Foster wrote:
>
>
> On Fri, Oct 30, 2015 at 9:40 AM, Adrian Klaver
> <adrian(dot)klaver(at)aklaver(dot)com <mailto:adrian(dot)klaver(at)aklaver(dot)com>
> <mailto:adrian(dot)klaver(at)aklaver(dot)com
> <mailto:adrian(dot)klaver(at)aklaver(dot)com>>> wrote:
>
> On 10/29/2015 05:38 PM, Dane Foster wrote:
>
> Hello,
>
> I think I've tripped over another mysq_fdw bug. I've
> filed a bug
> report
> on github already but just in case the problem is w/ my
> query I
> figured
> I would post it here in case someone sees something
> obvious.
>
> The error message I get is: null value in column
> "location" violates
> not-null constraint.
>
> The DDL is here:
> https://github.com/EnterpriseDB/mysql_fdw/issues/71
>
> For the record I know top posting is a crime against
> god and
> humanity
> but I feel justified because this post is not directly
> related
> to the
> original. So there! Granted it's in the same milieu;
> and yes this
> current sentence exists for the sole purpose of me
> being able to
> use the
> word milieu because the opportunity to use it is so few
> and far
> between.
>
> ​INSERT INTO series (cid, day, title, description,
> location,
> duration,
> can_join)
> SELECT
> cid,
> row_number() OVER (PARTITION BY cid ORDER BY
> lower(duration)),
> title,
> description,
> location,
> duration,
> can_join
> FROM (
> SELECT
> cid,
> title,
> description,
> can_join::BOOLEAN,
> (SELECT label FROM _locations WHERE
> loc=location) AS
> location,
> ('[' || starts || ', ' || (starts + INTERVAL '4
> HOUR') ||
> ']')::TSZ_PERIOD AS duration
> FROM
> _series
> ) AS v​
>
> ​Regards,​
>
>
> So what do you get when you do?:
>
> SELECT
> cid,
> title,
> description,
> can_join::BOOLEAN,
> (SELECT label FROM _locations WHERE loc=location) AS
> location,
> ('[' || starts || ', ' || (starts + INTERVAL '4
> HOUR') ||
> ']')::TSTZRANGE AS duration
> FROM
> _series
> );
>
>
> Dane
>
>
>
>
> --
> Adrian Klaver
> adrian(dot)klaver(at)aklaver(dot)com <mailto:adrian(dot)klaver(at)aklaver(dot)com>
> <mailto:adrian(dot)klaver(at)aklaver(dot)com
> <mailto:adrian(dot)klaver(at)aklaver(dot)com>>
>
> ​
> I get rows of data, location and all.
>
>
> And when you do?:
>
> SELECT
> cid,
> row_number() OVER (PARTITION BY cid ORDER BY lower(duration)),
> title,
> description,
> location,
> duration,
> can_join
> FROM (
> SELECT
> cid,
> title,
> description,
> can_join::BOOLEAN,
> (SELECT label FROM _locations WHERE loc=location) AS location,
> ('[' || starts || ', ' || (starts + INTERVAL '4 HOUR') ||
> ']')::TSTZRANGE AS duration
> FROM
> _series
> ) AS v
>
>
>
> Dane
> ​
>
>
>
> --
> Adrian Klaver
> adrian(dot)klaver(at)aklaver(dot)com <mailto:adrian(dot)klaver(at)aklaver(dot)com>
>
>
> ​Before I answer your second query question I need to revise my response
> to the first. Yes the first query runs w/o an error message but the bit
> about "rows and all" was not entirely correct. Out of 313 rows only the
> first row had a location. The other 312 rows have NULL in the location
> column which is not supposed to happen. To verify this I changed the
> table names and removed the PostgreSQL transformations (i.e., use of ||
> and :: for casting) and ran the query against the MySQL database; it
> returned 313 rows of data, location and all.

You would think that would also cause an issue with the first row that
is returned correctly. My suspicion is with this:

row_number() OVER (PARTITION BY cid ORDER BY lower(duration))

What happens if you run the full SELECT without it?

>
> Now that I've cleared that up.
>
> Your second query also runs w/o any error messages but like the first
> only the first row has a non NULL value in the location column.
>
>
>
> Dane
> ​
>

--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com