When using a LIMIT to reduce the number of rows
read, JSONEachRow format would always read an
extra row as it triggered a scan to seek the
EOF or beginning of the next row. This is not
an issue with physical tables, but it is
for streaming tables as an extra row is
unintentionally consumed on each read.
* Log query id in executeQuery; Better type mismatch error; change format in report tool
* Better log query_id
* fix message
* Use c++11 thread_local instaed of gcc's __thread
* lock mutex before notifying waiting thread in sync insertion into distributed [#CLICKHOUSE-3379]
* Cmake: fix build without downloaded submodules (#1379)
* fix
* do not write out partition and minmax index files for old MergeTreeData format
* download the part from another replica if there are missing or extra files
The tryGet() operation creates a 1MB buffer on stack. This may or
may not work depending on the default stack size for threads,
whether the stack protector is enabled or not, recursion depth,
and the actual value size.
This is probably going to slow down some ZK operations, but I don't
see how else this could work reliably with the existing API.
In the current version of Poco, unsigned long no longer aliases to
UInt64 with LP64. The size_t aliases to unsigned long with clang,
so all the uses of size_t instead of UInt64 when interacting with
Poco interfaces are gone. I replaced uses with UInt64 where it makes
sense, and added an overloaded function for readVarUInt() to support size_t.
The built-in clang doesn’t support value() for
`std::experimental::optional`. It however supports
dereference operator, which is basically the
same thing:
```
/clickhouse/dbms/src/DataStreams/NullableAdapterBlockInputStream.cpp:83:67: error: call to unavailable member function 'value':
res.insert({elem.column, elem.type, rename[i].value()});
~~~~~~~~~~^~~~~
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/experimental/optional:547:17: note: candidate function has been explicitly made unavailable
value_type& value()
^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/experimental/optional:539:33: note: candidate function has been explicitly made unavailable
constexpr value_type const& value() const
```
The function is rewritten to avoid allocations on every insert with
Field deserialising each array. The key type is now specialized,
so it can be accessed directly. The value type is variant type,
but only individual values are deserialised (which is cheap, since they're PODs).
The function also support summing of multiple columns by the same key.
The SummingSortedBlockInputStream uses the function in case of
Nested structure with one numeric key and many values to sum.
This replaces custom summation function implementations with an implementation
using built-in aggregation functions (sum and sumMap). The goal is to be able to
use specialized variants of aggregation functions, and to have a single
efficient implementation.
This is basically useful for testing SummingSortedBlockInputStream
against the AggregatingBlockInputStream, which are used in the
{Summing,Aggregating}MergeTree table engines respectively.
