SQL with JOIN and columns ARRAY, will call function ColumnArray::replicate. At this pr,
we implement replicate for ARRAY type, to support SQL like this:
`SELECT count(lo_array),count(d_array),SUM(lo_extendedprice*lo_discount) AS REVENUE FROM lineorder, date WHERE lo_orderdate = d_datekey AND d_year = 1993 AND lo_discount BETWEEN 1 AND 3 AND lo_quantity < 25;`
## Design:
For now, there are two categories of types in Doris, one is for scalar types (such as int, char and etc.) and the other is for composite types (array and etc.). For the sake of performance, we can cache type info of scalar types globally (unique objects) due to the limited number of scalar types. When we consider the composite types, normally, the type info is generated in runtime (we can also use some cache strategy to speed up). The memory thereby should be reclaimed when we create type info for composite types.
There are a lots of interfaces to get the type info of a specific type. I reorganized those as the following describes.
1. `const TypeInfo* get_scalar_type_info(FieldType field_type)`
The function is used to get the type info of scalar types. Due to the cache, the caller uses the result **WITHOUT** considering the problems about memory reclaim.
2. `const TypeInfo* get_collection_type_info(FieldType sub_type)`
The function is used to get the type info of array types with just **ONE** depth. Due to the cache, the caller uses the result **WITHOUT** considering the problems about memory reclaim.
3. `TypeInfoPtr get_type_info(segment_v2::ColumnMetaPB* column_meta_pb)`
4. `TypeInfoPtr get_type_info(const TabletColumn* col)`
These functions are used to get the type info of **BOTH** scalar types and composite types. The caller should be responsible to manage the resources returned.
#### About the new type `TypeInfoPtr`
`TypeInfoPtr` is an alias type to `unique_ptr` with a custom deleter.
1. For scalar types, the deleter does nothing.
2. For composite types, the deleter reclaim the memory.
By analyzing the callers of `get_type_info`, these classes should hold TypeInfoPtr:
1. `Field`
2. `ColumnReader`
3. `DefaultValueColumnIterator`
Other classes are either constructed by the foregoing classes or hold those, so they can just use the raw pointer of `TypeInfo` directly for the sake of performance.
1. `ScalarColumnWriter` - holds `Field`
1. `ZoneMapIndexWriter` - created by `ScalarColumnWriter`, use `type_info` from the field in `ScalarColumnWriter`
1. `IndexedColumnWriter` - created by `ZoneMapIndexWriter`, only uses scalar types.
2. `BitmapIndexWriter` - created by `ScalarColumnWriter`, uses `type_info` from the field in `ScalarColumnWriter`
1. `IndexedColumnWriter` - created by `BitmapIndexWriter`, uses `type_info` in `BitmapIndexWriter` and `BitmapIndexWriter` doesn't support `ArrayType`.
3. `BloomFilterIndexWriter` - created by `ScalarColumnWriter`, uses `type_info` from the field in `ScalarColumnWriter`
1. `IndexedColumnWriter` - created by `BloomFilterIndexWriter`, only uses scalar types.
2. `IndexedColumnReader` initializes `type_info` by the field type in meta (only scalar types).
3. `ColumnVectorBatch`
1. `ZoneMapIndexReader` creates `ColumnVectorBatch`, `ColumnVectorBatch` uses `type_info` in `IndexedColumnReader`
2. `BitmapIndexReader` supports scalar types only and it creates `ColumnVectorBatch`, `ColumnVectorBatch` uses `type_info` in `BitmapIndexReader`
3. `BloomFilterIndexWriter` supports scalar types only and it creates `ColumnVectorBatch`, `ColumnVectorBatch` uses `type_info` in `BloomFilterIndexWriter`
Currently, there are 2 status code in BE, one is common/Status.h,
and the other is olap/olap_define.h called OLAPStatus.
OLAPStatus is just an enum type, it is very simple and could not save many informations,
I will unify these code to common/Status.
1. solved the previous delayed unit test file size is too large (1.7G+) and the unit test link time is too long problem problems
2. Unify all unit tests into one file to significantly reduce unit test execution time to less than 3 mins
3. temporarily disable stream_load_test.cpp, metrics_action_test.cpp, load_channel_mgr_test.cpp because it will re-implement part of the code and affect other tests
I met a failure of reading hdfs files in broker load, the error message is unclear and
I spent a lot of time to locate the problem.
```
W0330 11:08:01.093812 2755268 broker_scan_node.cpp:364] Scanner[0] process failed. status=connect failed.
W0330 11:08:01.097682 2018787 fragment_mgr.cpp:234] Got error while opening fragment 712ae2b848324cb6-94a83d646173c1e9: Internal error: connect failed.
W0330 11:08:01.097702 2018787 tablet_sink.cpp:148] connect failed.
```
We should add more information when connect to hdfs failed.
Current situation of Doris is that the cluster is balanced, but the disks of a backend may be unbalanced.
for example, backend A have two disks: disk1 and disk2, disk1's usage is 98%, but disk2's usage is only 40%.
disk1 is unable to take more data, therefore only one disk of backend A can take new data,
the available write throughput of backend A is only half of its ability, and we can not resolve this through load or
partition rebalance now.
So we introduce disk rebalancer, disk rebalancer is different from other rebalancer(load or partition)
which take care of cluster-wide data balancing. it takes care about backend-wide data balancing.
[For more details see #8550](https://github.com/apache/incubator-doris/issues/8550)
Add a new column-type to speed up the approximation of quantiles.
1. The new column-type is named `quantile_state` with fixed aggregation function `quantile_union`, which stores the intermediate results of pre-aggregated approximation calculations for quantiles.
2. support pre-aggregation of new column-type and quantile_state related functions.
Early Design Documentation: https://shimo.im/docs/DT6JXDRkdTvdyV3G
Implement a new way of memory statistics based on TCMalloc New/Delete Hook,
MemTracker and TLS, and it is expected that all memory new/delete/malloc/free
of the BE process can be counted.
