This rule is rewrite project -> limit to limit -> project. The reason is we could get tree like project -> limit -> project -> other node. If we do not rewrite it. we could not merge the two project into one. And if we has more than one project on one node, the second one will overwrite the first one when translate. Then, be will core dump or return slot cannot find error.
in some case, the output slots of agg info may be materialized by call SlotDescriptor's materializeSrcExpr method, but not the intermediate slots. This pr set intermediate slots materialized info to keep consistent with output slots.
This PR introduce a new enum type `PushDownType`:
```
enum class PushDownType {
// The predicate can not be pushed down to data source
UNACCEPTABLE,
// The predicate can be pushed down to data source
// and the data source can fully evaludate it
ACCEPTABLE,
// The predicate can be pushed down to data source
// but the data source can not fully evaluate it.
PARTIAL_ACCEPTABLE
};
```
And derived class of VScanNode can override following method to determine whether to accept
a bianry/in/bloom filter/is null predicate:
```
PushDownType _should_push_down_binary_predicate();
PushDownType _should_push_down_in_predicate();
PushDownType _should_push_down_function_filter();
PushDownType _should_push_down_bloom_filter();
PushDownType _should_push_down_is_null_predicate();
```
When FE send cancel rpc to BE, it does not notify the wait_for_start() thread, so that the fragment will be blocked and occupy the execution thread.
Add a max wait time for wait_for_start() thread. So that it will not block forever.
When select large number of data from a table, the profile will show that:
- ScannerCtxSchedCount: 2.82664M(2826640)
But there is only 8 times of ScannerSchedCount, most of them are busy running.
After improvement, the ScannerCtxSchedCount will be reduced to only 10.
# Proposed changes
First step of #12303
## Problem summary
This is the first step for supporting rollup index selection for aggregate/unique key OLAP table.
This PR aims to select rollup index when the aggregate node is present and the aggregate function matches the value type. So pre-aggregation is turned on by default. Cases that pre-aggregation should be turned off will be addressed in the next PR.
Main steps for rollup index selection:
1. filter rollup indexes with all the required columns.
2. filter rollup indexes that match the key prefix most.
3. order the rollup indexes by row count, column count, rollup index id.
TODO remaining:
1. address cases that pre-aggregation should be turned off. (next PR)
2. add more test cases.
Refactor
- Add `Project.getSlotToProducer` to extract a map from the project output slot to its producing expression.
- Add `Filter.getConjuncts` to split the filter condition to conjunctive predicates.
- Move the usage of `ExpressionReplacer` to `ExpressionUtils.replace(expr, replaceMap)` to simplify the code.
When the current non-correlated subquery is executed, an error will be reported that the corresponding column cannot be found.
The reason is that the tupleID of the child obtained in visitPhysicalNestedLoopJoin is not consistent with the child.
The non-correlated subquery will trigger this bug because it uses crossJoin.
At the same time, sub-query regression tests for non-associative and complex scenarios have been added
Co-authored-by: morrySnow <morrysnow@126.com>
Support function registry.
The classes:
- BuiltinFunctions: contains the built-in functions list
- FunctionRegistry: used to register scalar functions and aggregate functions, it can find the function by name
- FunctionBuilder: used to resolve a BoundFunction class, extract the constructor, and build to a BoundFunction by arguments(`List<Expression>`)
Register example: you can add built-in functions in the list for simplicity
```java
public class BuiltinFunctions implements FunctionHelper {
public final List<ScalarFunc> scalarFunctions = ImmutableList.of(
scalar(Substring.class, "substr", "substring"),
scalar(WeekOfYear.class),
scalar(Year.class)
);
public final ImmutableList<AggregateFunc> aggregateFunctions = ImmutableList.of(
agg(Avg.class),
agg(Count.class),
agg(Max.class),
agg(Min.class),
agg(Sum.class)
);
}
```
Note:
- Currently, we only support register scalar functions add aggregate functions, we will support register table functions.
- Currently, we only support resolve function by function name and difference arity, but can not resolve the same arity override function, e.g. `some_function(Expression)` and `some_function(Literal)`
when uncorrelated subquery in having predicates, having's output will appears one slot from subquery by mistake. This PR fix it by always add a project on the top of having.
Co-authored-by: mch_ucchi <organic_chemistry@foxmail.com>
Failed when reading parquet file with many columns(>1600).
mysql> select int_col from types_sf100_r100w limit 5;
ERROR 1105 (HY000): errCode = 2, detailMessage = Couldn't deserialize thrift msg:
TProtocolException: Invalid data
parse_thrift_footer uses fixed length buffer(=64k) to read parquet footer, but the meta data of a parquet file with 1600 columns can exceed 5MB.
Therefore, the buffer size needs to be applied according to the actual length.
1. For query with 1656 union, the plan thrift size will be reduced from 400MB+ to 2MB.
This optimization is introduced from #4904, but lost after #9720
2. Disable ExprSubstitutionMap.verify when debug is disable.
So that the plan time of query with 1656 union will be reduced from 20s to 2s
The original statistic derive calculate algorithm rely on NDV and other column statistics. But we cannot get these stats in product environment.
This PR change these operator's stats calc algorithm to use a DEFAULT RATIO variable instead of column statistics.
We should change these algorithm when we could get column stats in product environment
Implement uncheckedCast on VarcharLiteral for a temp way to let TimestampArithmetic work.
We should remove these code and do implicit cast in TypeCoercion rule in future.
Just as legacy planner, Nereids parse all fractional literal to decimal.
In the future, we will add more syntax for user to control the fractional literal type.
