Solving a ClickHouse Connection Puzzle

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Encountering the Error ๐Ÿ”—

It all started with an error that seemed straightforward but proved to be elusive. Determined to get to the root of the problem, I set a breakpoint and started tracing the issue.

Initial Breakpoint Screenshot

Unraveling the Packet Mystery ๐Ÿ”—

The first piece of the puzzle was a packet labeled 72. A quick look at the ASCII table revealed that 72 corresponded to the character H. This was unexpected and piqued my curiosity.

The Mystery of H ๐Ÿ”—

Further investigation led me to examine the complete message received by the client. Surprisingly, it was only reading the first part of the raw data.

Full Message Screenshot

On inspecting the raw data in the debugger, I discovered that the H was part of an HTTP/1.1 400 Bad Request response. This was a significant clue.

Raw Data Screenshot

Analyzing the Handshake Message ๐Ÿ”—

I then scrutinized the handshake message sent to the server. It appeared standard, but the server’s response suggested otherwise. I meticulously checked each byte, searching for any anomalies.

The Resolution: A Simple Oversight ๐Ÿ”—

Eventually, the solution was found in an often-overlooked detail โ€“ the port number. I had been using port 8123 (intended for HTTP) instead of port 9000 (for TCP). This small misconfiguration was the root cause of the issue.