# Proposed changes
Issue Number: close#6238
Co-authored-by: HappenLee <happenlee@hotmail.com>
Co-authored-by: stdpain <34912776+stdpain@users.noreply.github.com>
Co-authored-by: Zhengguo Yang <yangzhgg@gmail.com>
Co-authored-by: wangbo <506340561@qq.com>
Co-authored-by: emmymiao87 <522274284@qq.com>
Co-authored-by: Pxl <952130278@qq.com>
Co-authored-by: zhangstar333 <87313068+zhangstar333@users.noreply.github.com>
Co-authored-by: thinker <zchw100@qq.com>
Co-authored-by: Zeno Yang <1521564989@qq.com>
Co-authored-by: Wang Shuo <wangshuo128@gmail.com>
Co-authored-by: zhoubintao <35688959+zbtzbtzbt@users.noreply.github.com>
Co-authored-by: Gabriel <gabrielleebuaa@gmail.com>
Co-authored-by: xinghuayu007 <1450306854@qq.com>
Co-authored-by: weizuo93 <weizuo@apache.org>
Co-authored-by: yiguolei <guoleiyi@tencent.com>
Co-authored-by: anneji-dev <85534151+anneji-dev@users.noreply.github.com>
Co-authored-by: awakeljw <993007281@qq.com>
Co-authored-by: taberylyang <95272637+taberylyang@users.noreply.github.com>
Co-authored-by: Cui Kaifeng <48012748+azurenake@users.noreply.github.com>
## Problem Summary:
### 1. Some code from clickhouse
**ClickHouse is an excellent implementation of the vectorized execution engine database,
so here we have referenced and learned a lot from its excellent implementation in terms of
data structure and function implementation.
We are based on ClickHouse v19.16.2.2 and would like to thank the ClickHouse community and developers.**
The following comment has been added to the code from Clickhouse, eg:
// This file is copied from
// https://github.com/ClickHouse/ClickHouse/blob/master/src/Interpreters/AggregationCommon.h
// and modified by Doris
### 2. Support exec node and query:
* vaggregation_node
* vanalytic_eval_node
* vassert_num_rows_node
* vblocking_join_node
* vcross_join_node
* vempty_set_node
* ves_http_scan_node
* vexcept_node
* vexchange_node
* vintersect_node
* vmysql_scan_node
* vodbc_scan_node
* volap_scan_node
* vrepeat_node
* vschema_scan_node
* vselect_node
* vset_operation_node
* vsort_node
* vunion_node
* vhash_join_node
You can run exec engine of SSB/TPCH and 70% TPCDS stand query test set.
### 3. Data Model
Vec Exec Engine Support **Dup/Agg/Unq** table, Support Block Reader Vectorized.
Segment Vec is working in process.
### 4. How to use
1. Set the environment variable `set enable_vectorized_engine = true; `(required)
2. Set the environment variable `set batch_size = 4096; ` (recommended)
### 5. Some diff from origin exec engine
https://github.com/doris-vectorized/doris-vectorized/issues/294
## Checklist(Required)
1. Does it affect the original behavior: (No)
2. Has unit tests been added: (Yes)
3. Has document been added or modified: (No)
4. Does it need to update dependencies: (No)
5. Are there any changes that cannot be rolled back: (Yes)
Add a new field `Lag` in result of `show routine load` stmt.
`Lag: {"0":10, "1":0}` means kafka partition 0 has 10 msg behind and partition 1 is update-to-date.
Users can directly query the data in the hive table in Doris, and can use join to perform complex queries without laboriously importing data from hive.
Main changes list below:
FE:
Extend HiveScanNode from BrokerScanNode
HiveMetaStoreClientHelper communicate with HIVE and HDFS.
BE:
Treate HiveScanNode as BrokerScanNode, treate HiveTable as BrokerTable.
broker_scanner.cpp: suppot read column from HDFS path.
orc_scanner.cpp: support read hdfs file.
POM:
Add hive.version=2.3.7, hive-metastore and hive-exec
Add hadoop.version=2.8.0, hadoop-hdfs
Upgrade commons-lang to fix incompatiblity of Java 9 and later.
Thrift:
Add THiveTable
Add read_by_column_def in TBrokerRangeDesc
some user do not know Doris support type boolean, they use TINYINT,
so i add type BOOLEAN when enter 'help create table' in mysql client.
currently, type BOOLEAN size is 1 byte, but the value of boolean column only in {0,1} ,
which waste some memory, and i want change it's implement to 1 bit in the future.
```
EXPORT TABLE xxx
...
PROPERTIES
(
"label" = "mylabel",
...
);
```
And than user can use label to get the info by SHOW EXPORT stmt:
```
show export from db where label="mylabel";
```
For compatibility, if not specified, a random label will be used. And for history jobs, the label will be "export_job_id";
Not like LOAD stmt, here we specify label in `properties` because this will not cause grammatical conflicts,
and there is no need to modify the meta version of the metadata.
I tested hex in a 1000w times for loop with random numbers，
old hex avg time cost is 4.92 s，optimize hex avg time cost is 0.46 s which faster nearly 10x.
1. Fix bug of UNKNOWN Operation Type 91
2. Support using resource_tag property of user to limit the usage of BE
3. Add new FE config `disable_tablet_scheduler` to disable tablet scheduler.
4. Add documents for resource tag.
5. Modify the default value of FE config `default_db_data_quota_bytes` to 1PB.
6. Add a new BE config `disable_compaction_trace_log` to disable the trace log of compaction time cost.
7. Modify the default value of BE config `remote_storage_read_buffer_mb` to 16MB
8. Fix `show backends` results error
9. Add new BE config `external_table_connect_timeout_sec` to set the timeout when connecting to odbc and mysql table.
10. Modify issue template to enable blank issue, for release note or other specific usage.
11. Fix a bug in alpha_row_set split_range() function.
for issue #6474
```sql
create table test.table1 like test.table with rollup r1,r2 -- copy some rollup
create table test.table1 like test.table with rollup all -- copy all rollup
create table test.table1 like test.table -- only copy base table
```
