Sorry for the clickbaity title. This is about static method
ConnectionTimeouts::getHTTPTimeouts(). It was be declared in header
IO/ConnectionTimeouts.h, and defined in header
IO/ConnectionTimeoutsContext.h (!). This is weird and caused issues with
linking on s390x (##45520). There was an attempt to fix some
inconsistencies (#45848) but neither did @Algunenano nor me at first
really understand why the definition is in the header.
Turns out that ConnectionTimeoutsContext.h is only #include'd from
source files which are part of the normal server build BUT NOT part of
the keeper standalone build (which must be enabled via CMake
-DBUILD_STANDALONE_KEEPER=1). This dependency was not documented and as
a result, some misguided workarounds were introduced earlier, e.g.
0341c6c54b
The deeper cause was that getHTTPTimeouts() is passed a "Context". This
class is part of the "dbms" libary which is deliberately not linked by
the standalone build of clickhouse-keeper. The context is only used to
read the settings and the "Settings" class is part of the
clickhouse_common library which is linked by clickhouse-keeper already.
To resolve this mess, this PR
- creates source file IO/ConnectionTimeouts.cpp and moves all
ConnectionTimeouts definitions into it, including getHTTPTimeouts().
- breaks the wrong dependency by passing "Settings" instead of "Context"
into getHTTPTimeouts().
- resolves the previous hacks
