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Reuse keep-alive HTTP connections after a fully read response - #587
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The driver dropped the keep-alive connection after every request. Before sending a new request, and when closing a cursor, it checked the previous response stream with `in->fail() || !in->eof()`. AmortizedIStreamReader reads ahead in blocks of at least 8 KB, so the read that reaches the end of the body always stops short and sets both eofbit and failbit. That is the normal end-of-response state, but the check treated it as an error and reset the session, so every query opened a new TCP connection (and a new TLS handshake over HTTPS). Replace the check with Statement::resetConnectionIfNeeded(), which resets the session only when the stream is bad, the body has unread bytes, or the session recorded a socket exception. closeCursor() now destroys the result reader before inspecting the stream: the reader's destructor puts back pre-read bytes, which clears eofbit and can set badbit, so checking first could reuse a connection that still has unread rows on the wire. Test server: serve multiple requests per connection so keep-alive can actually be exercised, bind to an ephemeral loopback port instead of the hard-coded 8124, count accepted connections, and guard the response data with a mutex. Fix the ANSI networking test binary, which loaded the Unicode driver, and size the zstd output buffer with ZSTD_compressBound so compressing an empty body no longer produces a zero-length buffer. Add tests asserting the connection count across repeated selects and inserts (chunked, Content-Length, compressed), and that the driver reconnects when the server closes, when a cursor is closed with unread data, and after an incomplete response.
chernser
approved these changes
Sep 24, 2026
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The driver dropped the keep-alive connection after every request. Before sending a new request, and when closing a cursor, it checked the previous response stream with
in->fail() || !in->eof().AmortizedIStreamReaderreads ahead in blocks of at least 8 KB, so the read that reaches the end of the body always stops short and sets botheofbitandfailbit. That is the normal end-of-response state, but the check treated it as an error and reset the session, so every query opened a new TCP connection (and a new TLS handshake over HTTPS).