Got NPE inside ClickHouseResultSet.toString when LogProxy is enabled

[volyx]

It looks like field ru.yandex.clickhouse.response.ClickHouseResultSet#dateTimeTimeZone can be null in some conditions

java.lang.NullPointerException: null
  at ru.yandex.clickhouse.response.ClickHouseResultSet.toString(ClickHouseResultSet.java:824) ~[clickhouse-jdbc-0.3.1.jar:0.3.1]
  at java.lang.String.valueOf(String.java:2951) ~[?:?]
  at java.lang.StringBuilder.append(StringBuilder.java:168) ~[?:?]
  at ru.yandex.clickhouse.util.LogProxy.invoke(LogProxy.java:53) ~[clickhouse-jdbc-0.3.1.jar:0.3.1]
  at com.sun.proxy.$Proxy48.executeQuery(Unknown Source) ~[?:?]
  at ru.yandex.clickhouse.ClickHouseConnectionImpl.initConnection(ClickHouseConnectionImpl.java:91) ~[clickhouse-jdbc-0.3.1.jar:0.3.1]
  at ru.yandex.clickhouse.ClickHouseConnectionImpl.<init>(ClickHouseConnectionImpl.java:78) ~[clickhouse-jdbc-0.3.1.jar:0.3.1]
  at ru.yandex.clickhouse.ClickHouseDriver.connect(ClickHouseDriver.java:62) ~[clickhouse-jdbc-0.3.1.jar:0.3.1]
  at ru.yandex.clickhouse.BalancedClickhouseDataSource.ping(BalancedClickhouseDataSource.java:144) [clickhouse-jdbc-0.3.1.jar:0.3.1]

[phoesh]

#682 Look at it.

[zhicwu]

Thanks @volyx for reporting the issue. It's not supposed to be null. What's the output of select timezone() on your server? We can add null check when constructing result set and be more defensive in resultset.toString method, but it's better to find the root case.

@phoesh, the pull request is incorrect but I got your point. Are you suffering the same issue? What will you get from select timezone()? TimeZone.getTimeZone() is not supposed to return a null value but we can add a check there to enforce UTC will be used when things go wrong.

[phoesh]

@zhicwu I was suffering this issue. I have checked the null value is returning here ru.yandex.clickhouse.ClickHouseStatementImpl.updateResult getConnection().getTimeZone(). And why it will get null value?
See ru.yandex.clickhouse.ClickHouseConnectionImpl.initConnection try (Statement s = createStatement(); ResultSet rs = s.executeQuery("select timezone(), version()")). This createStatement() method construct the connection but the timezone is not set in the connection object. So it executes the query and ResultSet.toString appending ru.yandex.clickhouse.response.ClickHouseResultSet#dateTimeTimeZone string will throw this NPE.

[zhicwu]

Hahaha... good catch :) Fortunately this issue does not exist in the upcoming new client. I'll fix this over the weekend.