1. Add repeated PBlock.PColumnMeta.children field for complex data type, such as ARRAY;
2. change PBlock.PColumnMeta.name to optional, nested columns do not need to a column name;
This PR mainly changes:
1. Change the define of PBlock
The new PBlock consists of a set of PColumnMeta and a binary buffer.
The PColumnMeta records the metadata information of all columns in the Block,
while the buffer stores the serialized binary data of all columns.
2. Refactor the serialize/deserialize method of data type
Rewrite the `serialize()/deserialize()` of IDataType. And also add
a new method `get_uncompressed_serialized_bytes()` to get the total length
of uncompressed serialized data of a column.
3. Rewrite the serialize/deserialize method of Block
Now, when serializing a Block to PBlock, it will first get the total length
of uncompressed serialized data of all columns in this Block, and then allocate
the memory to write the serialized data to the buffer.
4. Use brpc attachment to transmit the serialized column data
This PR mainly changes:
1. Fix bug when enable `transfer_data_by_brpc_attachment`
In `data_stream_sender`, we will send a serialized PRowBatch data to multiple Channels.
And if `transfer_data_by_brpc_attachment` is enabled, we will mistakenly clear the data in PRowBatch
after sending PRowBatch to the first Channel.
As a result, the following Channel cannot receive the correct data, causing an error.
So I use a separate buffer instead of `tuple_data` in PRowBatch to store the serialized data
and reuse it in multiple channels.
2. Fix bug that the the offset in serialized row batch may overflow
Use int64 to replace int32 offset. And for compatibility, add a new field `new_tuple_offsets` in PRowBatch.
Transfer RowBatch in Protobuf Request to Controller Attachment,
when the maximum length of the RowBatch in the Protobuf Request is exceeded.
This can avoid reaching the upper limit of the Protobuf Request length (2G),
and it is expected that performance can be improved.
This CL mainly changes:
1. Support `SELECT INTO OUTFILE` command.
2. Support export query result to a file via Broker.
3. Support CSV export format with specified column separator and line delimiter.
Record query consumption into fe audit log. Its basic mode of work is as follows, one of instance of parent plan is responsible for accumulating sub plan's consumption and send to it's parent, BE coordinator will get total consumption because it's a single instance.
