[BUG] - jdbc driver throw exception when count() is used with JSONEachRow

[jonathanyuechun]

Valid SQL statement with clickhouse-client:

dev.server.io :) select count() from tutorial.visits_v1 format JSONEachRow

SELECT count()
FROM tutorial.visits_v1
FORMAT JSONEachRow

Query id: afa202e1-54cb-4c64-a628-f8d0711c71dc

{"count()":"1680609"}
↑ Progress: 1.00 rows, 4.10 KB (160.98 rows/s., 660.65 KB/s
1 rows in set. Elapsed: 0.006 sec. 
                 select count() from tutorial.visits_v1 format JSONEachRow

Snippet:

  public static void main(String... args) throws SQLException {
    String url = "jdbc:clickhouse://localhost:8123/tutorial";
    ClickHouseProperties properties = new ClickHouseProperties();
    // set connection options - see more defined in ClickHouseConnectionSettings
    properties.setClientName("Agent #1");
    // set default request options - more in ClickHouseQueryParam
    properties.setSessionId("default-session-id");
    ClickHouseDataSource dataSource = new ClickHouseDataSource(url, properties);

    String sql = "select count() from visits_v1 format JSONEachRow";
    Map<ClickHouseQueryParam, String> additionalDBParams = new HashMap<>();
    // set request options, which will override the default ones in ClickHouseProperties
    additionalDBParams.put(ClickHouseQueryParam.SESSION_ID, "new-session-id");
    List<String> datas = new ArrayList<>();
    try (ClickHouseConnection conn = dataSource.getConnection();
        ClickHouseStatement stmt = conn.createStatement();
        ResultSet rs = stmt.executeQuery(sql, additionalDBParams)) {
      while (rs.next()) {
        datas.add(rs.getString(1));
      }
    }
    System.out.println(datas.size());
  }

throws:

Exception in thread "main" ru.yandex.clickhouse.except.ClickHouseUnknownException: ClickHouse exception, code: 1002, host: localhost, port: 8123; ClickHouse response without column types
	at ru.yandex.clickhouse.except.ClickHouseExceptionSpecifier.getException(ClickHouseExceptionSpecifier.java:92)
	at ru.yandex.clickhouse.except.ClickHouseExceptionSpecifier.specify(ClickHouseExceptionSpecifier.java:56)
	at ru.yandex.clickhouse.except.ClickHouseExceptionSpecifier.specify(ClickHouseExceptionSpecifier.java:25)
	at ru.yandex.clickhouse.ClickHouseStatementImpl.executeQuery(ClickHouseStatementImpl.java:351)
	at ru.yandex.clickhouse.ClickHouseStatementImpl.executeQuery(ClickHouseStatementImpl.java:324)
	at ru.yandex.clickhouse.ClickHouseStatementImpl.executeQuery(ClickHouseStatementImpl.java:319)
	at org.thales.punch.server.services.api.TestMe.main(TestMe.java:35)
Caused by: java.lang.IllegalArgumentException: ClickHouse response without column types
	at ru.yandex.clickhouse.response.ClickHouseResultSet.<init>(ClickHouseResultSet.java:107)
	at ru.yandex.clickhouse.ClickHouseStatementImpl.createResultSet(ClickHouseStatementImpl.java:1121)
	at ru.yandex.clickhouse.ClickHouseStatementImpl.updateResult(ClickHouseStatementImpl.java:224)
	at ru.yandex.clickhouse.ClickHouseStatementImpl.executeQuery(ClickHouseStatementImpl.java:344)
	... 3 more

[zhicwu]

Similar issue as #725. For text format without header, we should use something like results Nullable(String) as default.

[jonathanyuechun]

@zhicwu Thanks for the quick reply. May i know the date the next release is scheduled for ?

[zhicwu]

@zhicwu Thanks for the quick reply. May i know the date the next release is scheduled for ?

I'm aiming a release in early Oct, during holidays in China :)

[jonathanyuechun]

@zhicwu Hi does the merged of : #736 fixed this issue ?

[zhicwu]

@zhicwu Hi does the merged of : #736 fixed this issue ?

The PR is a brand new Java client along with implementation built on top of gRPC. It's related but not really a "fix" to the issue. I still need some more time to apply the changes to JDBC driver.

In case you want to try the experimental staff on develop branch:

1. enable gRPC on server
   https://github.com/ClickHouse/ClickHouse/blob/d3df1c02bca5483eca30df3d9d362607139e3ce5/programs/server/config.xml#L203-L204

2. use new client

ClickHouseNode server = ClickHouseNode.of("localhost", ClickHouseProtocol.GRPC, 9100, "tutorial");
// important to close both client and response if you won't reuse them later
try (ClickHouseClient client = ClickHouseClient.newInstance(server.getProtocol());
    ClickHouseResponse resp = client.connect(server).format(ClickHouseFormat.JSONEachRow)
      .query("select count() from visits_v1").execute().get()) {
    for (ClickHouseRecord r : resp.records()) {
      System.out.println(r.getValue(0).asLong());
    }
    // or simply:
    // System.out.println(resp.firstRecord().getValue(0).asLong());
}

[zhicwu]

In addition to Java client, it works in new JDBC driver as well.

select count() from system.query_log format JSONEachRow
--
results
{"count()":"6768"}

select count() from system.query_log format Markdown
--
results
| count() |
|-:|
| 6772 |