1. Spark can set the timestamp precision by the following configuration:
spark.sql.parquet.outputTimestampType = INT96(NANOS), TIMESTAMP_MICROS, TIMESTAMP_MILLIS
DATETIME V1 only keeps the second precision, DATETIME V2 keeps the microsecond precision.
2. If using DECIMAL V2, the BE saves the value as decimal128, and keeps the precision of decimal as (precision=27, scale=9). DECIMAL V3 can maintain the right precision of decimal
Currently we use rapidjson to parse json document, It's fast but not fast enough compare to simdjson.And I found that the simdjson has a parsing front-end called simdjson::ondemand which will parse json when accessing fields and could strip the field token from the original document, using this feature we could reduce the cost of string copy(eg. we convert everthing to a string literal in _write_data_to_column by sprintf, I saw a hotspot from the flamegrame in this function, using simdjson::to_json_string will strip the token(a string piece) which is std::string_view and this is exactly we need).And second in _set_column_value we could iterate through the json document by for (auto field: object_val) {xxx}, this is much faster than looking up a field by it's field name like objectValue.FindMember("k1").The third optimization is the at_pointer interface simdjson provided, this could directly get the json field from original document.
Two improvements have been added:
1. Translate parquet physical type into doris logical type.
2. Decode parquet column chunk into doris ColumnPtr, and add unit tests to show how to use related API.
# Proposed changes
Read and decode parquet physical type.
1. The encoding type of boolean is bit-packing, this PR introduces the implementation of bit-packing from Impala
2. Create a parquet including all the primitive types supported by hive
## Remaining Problems
1. At present, only physical types are decoded, and there is no corresponding and conversion methods with doris logical.
2. No parsing and processing Decimal type / Timestamp / Date.
3. Int_8 / Int_16 is stored as Int_32. How to resolve these types.
* [feature](planner): push limit to olapscan when meet sort.
* if olap_scan_node's sort_info is set, push sort_limit, read_orderby_key
and read_orderby_key_reverse for olap scanner
* There is a common query pattern to find latest time serials data.
eg. SELECT * from t_log WHERE t>t1 AND t<t2 ORDER BY t DESC LIMIT 100
If the ORDER BY columns is the prefix of the sort key of table, it can
be greatly optimized to read much fewer data instead of read all data
between t1 and t2.
By leveraging the same order of ORDER BY columns and sort key of table,
just read the LIMIT N rows for each related segment and merge N rows.
1. set read_orderby_key to true for read_params and _reader_context
if olap_scan_node's sort info is set.
2. set read_orderby_key_reverse to true for read_params and _reader_context
if is_asc_order is false.
3. rowset reader force merge read segments if read_orderby_key is true.
4. block reader and tablet reader force merge read rowsets if read_orderby_key is true.
5. for ORDER BY DESC, read and compare in reverse order
5.1 segment iterator read backward using a new BackwardBitmapRangeIterator and
reverse the result block before return to caller.
5.2 VCollectIterator::LevelIteratorComparator, VMergeIteratorContext return
opposite result for _is_reverse order in its compare function.
Co-authored-by: jackwener <jakevingoo@gmail.com>
Analyze schema elements in parquet FileMetaData, and generate the hierarchy of nested fields.
For exmpale:
1. primitive type
```
// thrift:
optional int32 <column-name>;
// sql definition:
<column-name> int32;
```
2. nested type
```
// thrift:
optional group <column-name> (LIST) {
repeated group bag {
optional group array_element (LIST) {
repeated group bag {
optional int32 array_element
}
}
}
}
// sql definition:
<column-name> array<array<int32>>
```
When a rowset includes multiple segments, segments rows will be merged in generic_iterator but merged_rows is not maintained. Compaction will failed in check_correctness.
Co-authored-by: yixiutt <yixiu@selectdb.com>
add codes for collect_list and collect_set and update regression output, before output format for ARRAY(string) already changed.
Co-authored-by: cambyzju <zhuxiaoli01@baidu.com>
When the length of `Tuple/Block data` is greater than 2G, serialize the protoBuf request and embed the
`Tuple/Block data` into the controller attachment and transmit it through http brpc.
This is to avoid errors when the length of the protoBuf request exceeds 2G:
`Bad request, error_text=[E1003]Fail to compress request`.
In #7164, `Tuple/Block data` was put into attachment and sent via default `baidu_std brpc`,
but when the attachment exceeds 2G, it will be truncated. There is no 2G limit for sending via `http brpc`.
Also, in #7921, consider putting `Tuple/Block data` into attachment transport by default, as this theoretically
reduces one serialization and improves performance. However, the test found that the performance did not improve,
but the memory peak increased due to the addition of a memory copy.
Only support one level array now.
for example:
- nullable(array(nullable(tinyint))) is **support**.
- nullable(array(nullable(array(xx))) is **not support**.
* [Refactor][Bug-Fix][Load Vec] Refactor code of basescanner and vjson/vparquet/vbroker scanner
1. fix bug of vjson scanner not support `range_from_file_path`
2. fix bug of vjson/vbrocker scanner core dump by src/dest slot nullable is different
3. fix bug of vparquest filter_block reference of column in not 1
4. refactor code to simple all the code
It only changed vectorized load, not original row based load.
Co-authored-by: lihaopeng <lihaopeng@baidu.com>
