Decrease the default connection timeout to 3s to better align with the
default CQL query timeout of 10s.
The previous timeout allowed only one failover request in high availability
scenario before hitting the CQL query timeout.
By decreasing the timeout to 3s, we can perform up to three failover requests
within the CQL query timeout, which significantly improves the chances of
successfully completing the query in high availability scenarios.
Fixes: SCYLLADB-95
Pre-compute the total size and allocate a single uninitialized sstring
before copying the buffers, following the pattern from Seastar's
read_entire_stream_contiguous(). This avoids iterative reallocation
which is O(n^2) for large responses.
The connection timeout was 2 minutes and the keep-alive
timeout was 11 minutes. If a vector store node became unreachable, these
long timeouts caused significant delays before the system could recover,
negatively impacting high availability.
This change aligns both timeouts with the `request_timeout`
configuration, which defaults to 10 seconds. This allows for much
faster failure detection and recovery, ensuring that unresponsive nodes
are failed over from more quickly.
Move the response_content_to_sstring utility function from
vector_store_client.cc to utils.hh to enable reuse across
multiple files.
This refactoring prepares for the upcoming `client.cc` implementation
that will also need this functionality.
