Committer: maqroll <jluisoc@gmail.com>

Committer: maqroll <loteroc@gmail.com>

Display warning if clickhouse-client version is older than clickhouse-server.

Build fix

Rwlock sanitary update 1: removed weak_ptrs from implementation + added strong exception safety guarantee

Fix too early MySQL connection closure in MySQLBlockInputStreamream.cpp

Fix build error when cmake_minimum_required(3.12)

Split libdbms.so using object library

Use internal iteration over hash tables in Aggregator.

For compound hash tables such as the future StringHashMap, an
iterator-based API might be inefficient for iterating over a table or
for merging two tables, because:

1) the key has to be converted to a general format from a from a
   component-specific format, which may differ between the components;

2) the information about the component of the compound hash table to
   which the value belongs is lost, and has to be recalculated if the
   value is reinserted.

A more efficient approach is to use internal iteration, that is,
map-like functions, which avoids unnecessary conversions when iterating,
and allows to use an efficient component-wise approach when merging.

Now the linking time of incremental builds are around 1-2 seconds

Use separate key and "mapped" value references instead. This is
important for hash tables that do not store the key/"mapped" pair
directly, and cannot provide this interface without some runtime
overhead.

We don't need it anymore after we changed the hash table key memory
management to use callbacks. Removing this interface is important for
hash maps that do not store the key, such as FixedHashMap or the
prospective compound StringHashMap.

Use the right words

Based on std::list<>::emplace_back() and std::unordered_map<>::emplace()
provide strong exception safety, RWLockImpl is now changed to provide
the same level of exception safety.

* Typo fix.

* Links fix.

* Fixed links in docs.

* More fixes.

* Typo fix.

* Links fix.

* Typo fix.

* DOCAPI-7745: The first version.

* DOCAPI-7745: More text

* DOCAPI-7745: More text.

* Update docs/en/operations/settings/settings.md
Co-Authored-By: NIvan Blinkov <github@blinkov.ru>

* Update docs/en/query_language/misc.md
Co-Authored-By: NIvan Blinkov <github@blinkov.ru>

* DOCAPI-7745: Fixes.

Doc change. TTL examples

Doc change. Added some system queries (1st attempt).