1. The Mysql Go driver has a logic that terminates when it reads an EOF (end-of-file) and expects no data in the buffer. However, the front-end (FE) mistakenly returns an additional OK packet, which causes an exception to be thrown when reading the buffer.
2. Refactor some logic to support full prepared not just in where clause, like
```
select ?, ? from tbl
```
fe foldconstRule make array() function expr with const literal , and would not pass this array literal to be . but we should make fe array string output format is same with be array string output
Add JNI metrics, for example:
```
- HudiJniScanner: 0ns
- FillBlockTime: 31.29ms
- GetRecordReaderTime: 1m5s
- JavaScanTime: 35s991ms
- OpenScannerTime: 1m6s
```
Add three common performance metrics for JNI scanner:
1. `OpenScannerTime`: Time to init and open JNI scanner
2. `JavaScanTime`: Time to scan data and insert into vector table in java side
3. `FillBlockTime`: Time to convert java vector table to c++ block
And support user defined metrics in java side, for example: `OpenScannerTime` is a long time for the open process, we want to determine which sub-process takes too much time, so we add `GetRecordReaderTime` in java side.
The user defined metrics in java side can be attached to BE profile automatically.
Before, refresh the TabletsChannel profile in the LoadChannelMgr refresh memory statistics thread
This means that enable_profile=false will refresh and have performance loss in stress test
Problem:
when use select group_concat(distinct a, 'seg1'), group_concat(distinct b, 'seg2') ... Error would rised
Reason:
Group_concat function regard 'seg' as arguments also, so multi distinct column error would rised
Solved:
let Multi Distinct group_concat function only get first argument as real argument
The current column statistic cache loader is to load data from column_statistics olap table.
This pr is to change the cache loader logic to First load from column_statistics olap table, if no data was loaded, then load from table metadata. This is mainly to support fetch statistics data for external catalog using HMS or Iceberg api.
This is the first PR, next pr will implement the fetch logic for different external catalogs.
Two optimizations:
1. Insert string bytes directly to remove decoding&encoding process.
2. Use native reader to read the hudi base file if it has no log file. Use `explain` to show how many splits are read natively.
When we use a label to load data, this label can not be used twice. But when we execute a sql 'CLEAN LABEL [label] FROM db;', we hope that the same label can be used again.
However, the sql above does not work. This PR is fixing this problem.
