1. Supports sampling to collect statistics
2. Improved syntax for collecting statistics
3. Support histogram specifies the number of buckets
4. Tweaked some code structure
---
The syntax supports WITH and PROPERTIES, using the same syntax as before.
Column Statistics Collection Syntax:
```SQL
ANALYZE [ SYNC ] TABLE table_name
[ (column_name [, ...]) ]
[ [WITH SYNC] | [WITH INCREMENTAL] | [WITH SAMPLE PERCENT | ROWS ] ]
[ PROPERTIES ('key' = 'value', ...) ];
```
Column histogram collection syntax:
```SQL
ANALYZE [ SYNC ] TABLE table_name
[ (column_name [, ...]) ]
UPDATE HISTOGRAM
[ [ WITH SYNC ][ WITH INCREMENTAL ][ WITH SAMPLE PERCENT | ROWS ][ WITH BUCKETS ] ]
[ PROPERTIES ('key' = 'value', ...) ];
```
Illustrate：
- sync：Collect statistics synchronously. Return after collecting.
- incremental：Collect statistics incrementally. Incremental collection of histogram statistics is not supported.
- sample percent | rows：Collect statistics by sampling. Scale and number of rows can be sampled.
- buckets：Specifies the maximum number of buckets generated when collecting histogram statistics.
- table_name: The purpose table for collecting statistics. Can be of the form `db_name.table_name`.
- column_name: The specified destination column must be a column that exists in `table_name`, and multiple column names are separated by commas.
- properties：Properties used to set statistics tasks. Currently only the following configurations are supported (equivalent to the with statement)
- 'sync' = 'true'
- 'incremental' = 'true'
- 'sample.percent' = '50'
- 'sample.rows' = '1000'
- 'num.buckets' = 10
---
TODO:
- Supplement the complete p0 test
- `Incremental` statistics see #18653
add two phase read topn opt, the legacy planner's PR are:
- #15642
- #16460
- #16848
TODO:
we forbid limit(sort(project(scan))) since be core when plan has a project on the scan.
we need to remove this restirction after we fix be bug
Including below functions:
1. broker load
2. export
3. select into outfile
4. create repo and backup to gfs
after config env, use gfs like other hdfs system.
Probleam:
Dead loop cause of keep pushing analyze tasks into job stack. When doing analyze process and generate new operators, the same analyze rule would be pushed again, so it cause dead loop. And analyze process generate new operators when trying to bound order by key and aggregate function.
Solve:
We need to make it throw exception before complex analyze and rewrite process, so checking whether all expressions being bound should be done twice. One is done after bounding all expression, another is done after all analyze process in case of generate new expressions and new operators.
Example:
Cases were put in file: regression-test/suites/nereids_p0/except/test_bound_exception.groovy
`Export` syntax provides asynchronous export function, but `Export` does not achieve vectorization.
`Outfile` syntax provides synchronous export function`.
So we can reimplement the export syntax with oufile syntax.
Fix decimal v3 precision loss issues in the multi-catalog module.
Now it will use decimal v3 to represent decimal type in the multi-catalog module.
Regression Test: `test_load_with_decimal.groovy`
add catalog comment and create time info
```
create catalog hms_ctl
comment 'your comment'
properties (
'type'='hms',
'hive.metastore.uris' = 'thrift://xx:1234' );
```
Create Time will generate when the catalog is created.
use show catalogs and show create catalog to get these info.
estimate broadcast cost by an experience formula: beNumber^0.5 * rowCount
1. sender number and receiver number is not available at RBO stage now, so we use beNumber
2. senders and receivers work in parallel, that why we use square of beNumber
1. Evict the dropped stats from cache
2. Remove codes for the partition level stats collection
3. Disable analyze whole database directly
4. Fix the potential death loop in the stats cleaner
5. Sleep thread in each loop when scanning stats table to avoid excessive IO usage by this task.
`commons-lang`(1and2) is no longer maintained since 2011, and the official recommendation is `commons-lang3`, which can be smoothly upgraded to be compatible with `commons-lang`.
We use both dependencies in `fe`, which can be completely unified.
`PatternGenerator#generateTypePattern` has many meaningless loops, and IntegerRange is introduced for,
which is unnecessary. So I refactored it.
Tpc-h q10 and q5 benefit from this optimization.
For a given hash join condition, A=B, sometimes both A and B are reduced by filters. In this pr, both reductions are counted in join estimation.
For each release of Doris, there are some experimental features.
These feature may not stable or qualified enough, and user need to use it by setting config or session variables,
eg, set enable_mtmv = true, otherwise, these feature is disable by default.
We should explicitly tell user which features are experimental, so that user will notice that and decide whether to
use it.
Changes
In this PR, I support the experimental_ prefix for FE config and session variables.
Session Variable
Given enable_nereids_planner as an example.
The Nereids planner is an experimental feature in Doris, so there is an EXPERIMENTAL annotation for it:
@VariableMgr.VarAttr(..., expType = ExperimentalType.EXPERIMENTAL)
private boolean enableNereidsPlanner = false;
And for compatibility, user can set it by:
set enable_nereids_planner = true;
set experimental_enable_nereids_planner = true;
And for show variables, it will only show experimental_enable_nereids_planner entry.
And you can also see all experimental session variables by:
show variables like "%experimental%"
Config
Same as session variable, give enable_mtmv as an example.
@ConfField(..., expType = ExperimentalType.EXPERIMENTAL)
public static boolean enable_mtmv = false;
User can set it in fe.conf or ADMIN SET FRONTEND CONFIG stmt with both names:
enable_mtmv
experimental_enable_mtmv
And user can see all experimental FE configs by:
ADMIN SHOW FRONTEND CONFIG LIKE "%experimental%";
TODO
Support this feature for BE config
Only add experimental for:
enable_pipeline_engine
enable_nereids_planner
enable_single_replica_insert
and FE config:
enable_mtmv
enabel_ssl
enable_fqdn_mode
Should modify other config and session vars
