AFAIK MERGE has different concurrency semantics than what some DBMS call
UPSERT. PostgreSQL for example has a guaranteed insert or update
semantics whereas MERGE could end with constraint violation errors:
https://wiki.postgresql.org/wiki/UPSERT
Maybe it's worth adding that to the relational model after all?
Am 17.03.2020 um 07:17 schrieb Enrico Olivelli:
Il Lun 16 Mar 2020, 23:55 Julian Hyde <[email protected]> ha scritto:
Change the unparse operation for the dialect so that you generate UPSERT
rather than MERGE.
IIRC we did this for another dialect - maybe Phoenix.
Julian,
In my case (HerdDB) I need to see the presence of UPSERT in the RelNode
(EnumerableTableModify oŕ LogicalTableModify)
I saw the JIRA where you introduced UPSERT for Phoenix
I will check deeper, thanks
Enrico
Julian
On Mar 16, 2020, at 1:22 AM, Enrico Olivelli <[email protected]>
wrote:
Il Lun 16 Mar 2020, 09:06 Stamatis Zampetakis <[email protected]> ha
scritto:
Hi Enrico,
I have the impression that UPSERT is currently supported only at the
parser
level [1] so it seems normal that you don't find something relevant in
LogicalTableModify etc. Note that the SQL standard equivalent is the
MERGE
statement [2] but this also seems to be supported only at the
parser/validator level [2].
I guess it is not necessary to introduce more things in TableModify
since
UPSERT seems to be syntactic sugar. I think that most of the work can be
done in RelToSqlConverter [4] and possibly the rest of the code can be
left
intact.
I would like to sens a patch that introduces the ability to keep the
SqlInsert 'keywords' and pass them to TableModify?
Would it be a good approach?
The alternative is to introduce a new Operation but it would be a more
invasive change and I think it is not worth
Enrico
Best,
Stamatis
[1] https://issues.apache.org/jira/browse/CALCITE-492
[2] https://en.wikipedia.org/wiki/Merge_(SQL)
[3] https://issues.apache.org/jira/browse/CALCITE-985
[4]
https://github.com/apache/calcite/blob/d234626227954eefffe49f42abec65c649ffe3a6/core/src/test/java/org/apache/calcite/test/SqlToRelConverterTest.java#L2395
On Sun, Mar 15, 2020 at 6:53 PM Enrico Olivelli <[email protected]>
wrote:
Hi,
I am trying to use UPSERT but it seems to me that in TableModify (or
best LogicalTableModify or EnumerableTableModify) there is no way to
distinguish an INSERT from an UPSERT.
Am I missing something?
Regards
Enrico
