[jdbc-v2, client-v2] MAX_NUM_OF_CONNECTIONS doesn't limit connection.

[chernser]

Description

There was an issue https://github.com/ClickHouse/clickhouse-java/issues/1705 The problem still exists: https://github.com/ClickHouse/clickhouse-java/issues/1705#issuecomment-2898237536

Hi @Paultagoras, I have taken some new tests - I tried to re-run both my old tests and the project @f1llon provided - with clickhouse-jdbc version 0.8.6 and using JDBC-v2 classes (for example DataSourceImpl instead of the old ClickHouseDataSource). On one hand, I don't see anymore the Hikari CP issue I first submitted, so many thanks! But on the other hand, I still have some issues:

running @f1llon 's test project, I still have the old logs "route allocated: 1 of N; total allocated: 1 of N" using the "default" connection pool and running my own tests of concurrent reading, property ClientConfigProperties.HTTP_MAX_OPEN_CONNECTIONS is ignored: when I run a netstat command on my PC, the number of connections opened toward ClickHouse can be well above the one I set with the ClientConfigProperties.HTTP_MAX_OPEN_CONNECTIONS property.

Is it enough to initialize my DataSourceImpl with baseProperties.setProperty(ClientConfigProperties.HTTP_MAX_OPEN_CONNECTIONS.getKey(), "5"); and then use datasource.getConnection() to make this configuration effective or do I need to do anything else?

Still, thank you for your help!

Steps to reproduce

Error Log or Exception StackTrace

Expected Behaviour

Code Example

Configuration

Client Configuration

Environment

• [ ] Cloud
• Client version:
• Language version:
• OS:

ClickHouse Server

• ClickHouse Server version:
• ClickHouse Server non-default settings, if any:
• CREATE TABLE statements for tables involved:
• Sample data for all these tables, use clickhouse-obfuscator if necessary