@tsl-karlp WRT to this error

# env ENGINES=h2,clickhouse lein test
... snip....
INSERT FAILED:
["INSERT INTO venues (name, latitude, longitude, price, category_id) VALUES (?, 10.0646, -165.374, 3, 4)" "Red Medicine"]

ClickHouseException:
 Message: ClickHouse exception, code: 27, host: localhost, port: 8123; Code: 27, e.displayText() = DB::Exception: Cannot parse input: expected \t before: \n: (at row 1)

Row 1:
Column 0,   name: name,        type: String,  parsed text: "Red Medicine"
ERROR: Line feed found where tab is expected. It's like your file has less columns than expected.
And if your file have right number of columns, maybe it have unescaped backslash in value before tab, which cause tab has escaped.

, e.what() = DB::Exception

 SQLState: null
 Error Code: 27

I Googled that error really quick and found this: ClickHouse/ClickHouse#2652. So my guess is it seems like it's trying to insert your rows in CSV format. So perhaps start by looking for the reason it's trying to insert them that way instead of the normal SQL syntax

Thanks, @camsaul !

I don't think Clickhouse itself supports the normal SQL syntax for insertion. The clickhouse-jdbc wrapper, when using PreparedStatements, will POST something like:

INSERT INTO test FORMAT CSVWithNames
column1, column2, column3
1, 1, 1
2, 2, 2

Can the tests be modified to use PreaparedStatements, or should the Clickhouse tests have their own way of inserting the data?

Yeah it seems you might need to write a custom implementation of load-data! for Clickhouse so you can insert data in a way it likes

@camsaul :

Yeah it seems you might need to write a custom implementation of load-data! for Clickhouse so you can insert data in a way it likes

Is there a good example of doing this in the code?

Not really, all of the other SQL drivers support normal SQL INSERT syntax in some form or another. But It shouldn't be too hard.

guys, thanks for your great work

Unfortunately, we lack the bandwidth and Clojure experience to finish this feature. We'll gladly hand it off to more capable hands now.

I have got my hands on this, and found that the latest code in twosixlabs/metabase@acbb5ab doesn't compile because db.spec/clickhouse was used in metabase.driver.clickhouse/connection-details->spec. Fixed, squashed/rebased on current master, added some (mostly cosmetic) stuff. Tests still need the custom load-data!, and it still throws the NullPointerException with unreadable stacktrace when trying to execute a query via metabase web UI (but the good news are - the appropriate query in the ClickHouse is actually executed). Working on it. Clojure is fun, got into it last night.

My 50 cents about docs/developers-guide.md - it is a bit unclear in sense it is missing a straight and sufficient sequence of commands to get the working build from the ground. There is a ./bin/build, but it failed. The main problem was I had a JDK version 10, but I had some other obstacles too, which could have been resolved easier if there was a sequence of commands.

Also, the clickhouse-jdbc URI parsing should be fixed, since (as of version 0.1.42) it doesn't allow the hypens in the database name, and (as it looks for me) has a broken the default database name selection logic if it is not specified in URI.

@ei-grad thank you for your work!

Hey all,

Thank you for this PR and apologies for the long delay responding. We've recently done some work to support drivers as plugins in Metabase and as of the next release (v0.32) we will be asking driver developers to first publish new drivers in their own repositories (typically named metabase-*-driver). If the driver fully passes the driver tests we will link to it from our documentation, and if a driver gains significant usage we will consider merging it into Metabase itself.

Here is some documentation about publishing a driver as a plugin in a separate repository: https://github.com/metabase/metabase/wiki/Writing-a-Driver:-Packaging-a-Driver-&-Metabase-Plugin-Basics#drivers-shipped-as-3rd-party-plugins

Here are two example drivers: https://github.com/metabase/sudoku-driver https://github.com/metabase/crate-driver

We still have some work to do on the documentation. You can follow progress and provide feedback on that here: #9348

Thank you.

By the way, I noticed there's another Clickhouse driver: #9469 You all may want to consider consolidating efforts.