error autorefresh tableau about clickhouse4j

[doom369]

@xadhatter cool. We just released version 1.4.4. Thanks again for the details.

[doom369]

@kirill3000 Hello. Could you please provide more info. What operation is performed? What tool are you using? Maybe some logs?

[doom369]

@kirill3000 Closing due to lack of info. Please reopen when you can provide more info.

[xadhatter]

Hey @doom369 I am getting this error as well when using Tableau Desktop v2019.1.12 from a Windows machine. It only occurs on tables that have a Date datatype, DateTime works fine. I get the same error message using the official Yandex JDBC driver as well. Hitting ClickHouse server version 20.1.3.7.

I don't see anything useful in the logs other than the error message provided. Any help would be greatly appreciated. The driver is working great otherwise, thanks for all the hard work!

*edited to add ClickHouse server version

[doom369]

@xadhatter thanks for the details. Do you have some log of queries that Tableau performs? I would like to know what exactly query Tableau perform when it fails. It will help a lot.

[xadhatter]

@doom369 , here is my test setup:

CREATE TABLE test (
	id UInt32,
	date Date
)
ENGINE = MergeTree()
ORDER BY (id);

INSERT INTO test VALUES (0, '2020-01-01');

And the query that is coming from Tableau:

SELECT
	TOP 1000 1 AS `Number_of_Records`,
	`test`.`date` AS `date`,
	`test`.`id` AS `id`
FROM
	`default`.`test` `test`

If I plug that query into DBeaver using your driver it works fine. So I assume Tableau is calling some method in the JDBC driver to deal with the Date field that isn't implemented yet. I'll try to get the stack trace for you.

[doom369]

@xadhatter date is implemented within driver, so that's why I need precise method call to look into. If you don't know where to look in the Tableau - you can take a look into Clickhouse log:

/var/log/clickhouse-server/clickhouse-server.log
or here
/var/log/clickhouse-server/clickhouse-server.err.log

Those logs will tell you about queries that are executed and thus we will know what causes the issue. I'm eager to help, but need some entry point to start.

One more thing - clickhouse driver is not fully implemented and it has ~ 30 methods that throw UnsupportedOperationException. So precise method will help.

[xadhatter]

@doom369 Thanks so much for the fast responses. The query above is the exact query that Tableau is making. No errors on the clickhouse side.

Tableau is a bit of a black box, gotta love debugging closed source software. Here is the exact log coming out from Tableau...

{
    "ts": "2020-02-10T10:31:41.783",
    "pid": 8968,
    "tid": "2138",
    "sev": "warn",
    "req": "-",
    "sess": "-",
    "site": "-",
    "user": "-",
    "k": "compute-task-error",
    "v": {
        "msg": "java.lang.UnsupportedOperationException\nThere was a Java error.\n",
        "stack": "disabled",
        "task-name": "class BuildDataSourcePresModelTask"
    }
}

I'm trying to figure out how to enable "stack" which I hope will give us the Java stacktrace and the exact method, to make your life waay too easy ;) but struggling. I will reach out to Tableau support shortly if I can't figure it out.

[xadhatter]

@doom369 I've opened a support ticket with Tableau. I'll keep you posted.

[xadhatter]

@doom369 I win! Did a dirty hack:

try {
	throw new UnsupportedOperationException();
} catch (UnsupportedOperationException ex) {
	try (PrintWriter pw = new PrintWriter("C:\\Users\\xadhatter\\Downloads\\jdbcerror.log")) {
		ex.printStackTrace(pw);
	} catch (FileNotFoundException e) { }
	throw ex;
}

...and got...

java.lang.UnsupportedOperationException
	at cc.blynk.clickhouse.response.AbstractResultSet.getDate(AbstractResultSet.java:1864)
	at com.tableausoftware.data.ProtobufResultSet.addValue(ProtobufResultSet.java:268)
	at com.tableausoftware.data.ProtobufResultSet.addRow(ProtobufResultSet.java:202)
	at com.tableausoftware.data.ProtobufResultSet.fetchRows(ProtobufResultSet.java:154)
	at com.tableausoftware.data.ProtobufResultSet.nextBlock(ProtobufResultSet.java:179)

[xadhatter]

Realized the line numbers will be off. It's this method, https://github.com/blynkkk/clickhouse4j/blob/master/src/main/java/cc/blynk/clickhouse/response/AbstractResultSet.java#L641

[doom369]

@xadhatter pushed the fix and made temporary build:

https://github.com/blynkkk/clickhouse4j/releases/download/clickhouse4j-1.4.3/clickhouse4j-1.4.4-SNAPSHOT.jar

Please let me know if it works.

[xadhatter]

@doom369 It works! Thanks so much for the speedy fix. I'm new to ClickHouse but really liking it. Nice to see such a great community forming around it.