Hi JiaTao,
Very appreciated your iterative responses.
Best,
Trista
Juan Pan (Trista)
Senior DBA & PMC of Apache ShardingSphere
E-mail: panj...@apache.org
On 11/23/2020 18:17，JiaTao Tao<taojia...@gmail.com> wrote：
Emmmm, seems we don't have that.
Regards!
Aron Tao
Juan Pan <panj...@apache.org> 于2020年11月23日周一 下午2:54写道：
Hi JiaTao,
Very appreciated your share.
Actually, what I am confused about is how to make Calcite custom adaptor
works with other parsers.
For example, I use a non-Calcite parser to get the parsed result and
transform them into RelNode to tell Calcite, Hi, please use this RelNode
for the rest handling.
But I still implement a custom adaptor and wish Calcite can adopt them.
If I call Calcite JDBC, like `Driver.getConnection(Calcite_Conn)`, which
will bring Calcite parser to parser SQL instead of my own. : (
Is there any approach to make Calcite call the custom adapter and
third-party parser?
Best wishes,
Trista
Juan Pan (Trista)
Senior DBA & PMC of Apache ShardingSphere
E-mail: panj...@apache.org
On 11/23/2020 14:38，JiaTao Tao<taojia...@gmail.com> wrote：
Hi Juan Pan
As I said, you can archive this by "If you have to do this, you can either
generate SqlNode with Antlr OR transform your own AST tree to RelNode, you
can take a look at org.apache.calcite.sql2rel.SqlToRelConverter.", in fact,
hive does the same thing, you can take a look, it uses its own AST tree to
generate a RelNode tree.
Regards!
Aron Tao
Juan Pan <panj...@apache.org> 于2020年11月23日周一 下午1:04写道：
Hi JiaTao,
The reason we want to bypass Calcite parsing mainly contains two points.
First, as you said, we want to have a better query efficiency by only
parsing SQL one time. But from what you said, it looks like not a big deal.
Second, I am a bit concerned about the SQL supported capacity of Calcite.
[1] shows me the all supported SQLs. Is that in line with SQL92 or MySQL
5.x?
Currently, ShardingSphere parser has almost complete support for MySQL 8.0
and PostgreSQL, and basic support for SQLServer, Oracle, SQL92 [2] (As a
distributed Database middleware ecosystem, we have to do so).
Therefore, if we use Calcite parser, maybe we can not help users handle
some of the SQLs (Unsure).
Could you give me some hints to bypass the parsing of Calcite? Or maybe we
can not reach that goal?
Much appreciated your any points or reply. : )
Regards,
Trista
[1] https://calcite.apache.org/docs/reference.html
[2]
https://shardingsphere.apache.org/document/current/en/features/sharding/principle/parse
Juan Pan (Trista)
Senior DBA & PMC of Apache ShardingSphere
E-mail: panj...@apache.org
On 11/22/2020 16:17，JiaTao Tao<taojia...@gmail.com> wrote：
In fact, parse twice's impact is little, in Apache Kylin, every time we do
the transformation to SQL, we re-parse it.
What really takes time is validation (use metadata like getting it from
HMS) and optimization.
Regards!
Aron Tao
Juan Pan <panj...@apache.org> 于2020年11月22日周日 下午2:32写道：
Hi community,
Thanks for your attention. : )
Currently, Apache ShardingSphere community plans to leverage Apache
Calcite to implement federated SQL query,
i.e., the query from different database instances [1].
The draft approach is that we consider using the custom adaptor with the
SQL parser of ShardingSphere itself (Antlr involved),
and transforming the parsed result to the algebra of Calcite.
Lastly, Calcite will execute the SQLs by means of the custom adaptor.
Currently, I know the entrance of calling the custom adaptor is to use the
`DriverManager.getConnection(CalciteUrl)`, which will get Calcite's SQL
parsing involved.
But we want to avoid twice SQL parsing, which means we wish to ignore the
SQL parsing of CalciteN .
My question is that how we can leverage Calcite adaptor without using
Calcite parser.
Could you give me some hints?
Very appreciated your any help and reply.
Regards,
Trista
[1] https://github.com/apache/shardingsphere/issues/8284
Juan Pan (Trista)
Senior DBA & PMC of Apache ShardingSphere
E-mail: panj...@apache.org
