HTTP-session tests, assorted fixes

[hhell]

clickhouse-over-HTTP is not obsolete.

This is a preliminary pull request; merging various improvements and fixes to upstream.

[coveralls]

Coverage increased (+1.0%) to 92.988% when pulling e0b5ba6 on hhell:some_fixes into 2f79283 on xzkostyan:master.

[xzkostyan]

Yes, you are right. Clickhouse-over-http is not obsolete.

I want to made http transport in this project obsolete (not fully supported). I don't have enough efforts to maintain both transports. But PRs are always appreciated!

If you are working with large datasets tcp transport is faster, than http. Types conversion object -> str or str -> object is main bottleneck.
If you are not working with large datasets you will not notice difference between http and tcp.

[hhell]

I don't have enough efforts to maintain both transports

Best-case is you could at least avoid breaking it (thus the tests),

worst-case – it will have to have the tests in a different fork, and PRs with fixes.

Types conversion object -> str or str -> object is main bottleneck.

That's mostly the problem of the TSV parsing;

another modification (intended for a next PR) is streamed JSONCompact parsing

(also, see ClickHouse/ClickHouse#7841 ).

[xzkostyan]

I'll try to review PR by the end of this week.

[hhell]

bump.

[xzkostyan]

I need a little more time for brief review of whole changes. I'll return with feedback asap.

[hhell]

bump.