Supported SQL Operators and Expressions
This section describes the operators and expressions supported when using OmniStream, and the data types of the supported operators and expressions.
- The operators and expressions described in this section are used for Flink 1.16.3 only.
- The lists of supported operators and expressions display only the data types supported by or involved in OmniStream. The data types that are not displayed are not supported by OmniStream.
- If you use operators and expressions that are not supported by OmniStream, the execution plan will be rolled back to native execution, which deteriorates the performance.
- When you use the SQL Client interactive user interface to execute SQL statements, you are advised to export the execution result to the data table whose connector is blackhole. For details, see the execution mode of Nexmark Q0.
- Due to memory restrictions, only the Calc and LookupJoin operators are supported by default. To support other operators, set export FLINK_PERFORMANCE to false to enable environment variables.
The lists of operators and expressions use different symbols to indicate support states. See Table 1.
State |
Description |
|---|---|
S |
Indicates that OmniStream is supported. |
PS |
Indicates that OmniStream is partially supported and there are some restrictions. |
NS |
Indicates that OmniStream is not supported. |
NA |
Not applicable. No such input scenarios exist even on the native Flink engine. |
[Blank Cell] |
A scenario that is irrelevant or needs to be confirmed. |
Operator List
Table 2 lists the operators supported by OmniStream.
Operator |
BIGINT |
VARCHAR |
TIMESTAMP(3) |
|---|---|---|---|
Calc |
S |
S |
S |
Sink |
S |
S |
S |
Csv Source |
S |
S |
S |
Kafka Source |
S |
S |
S |
Kafka Sink |
S |
S |
S |
Join |
PS |
PS |
PS |
LookupJoin |
PS |
PS |
PS |
GroupAggregate |
PS |
PS |
PS |
LocalGroupAggregate |
PS |
PS |
PS |
GlobalGroupAggregate |
PS |
PS |
PS |
IncrementalGroupAggregate |
PS |
PS |
PS |
LocalWindowAggregate |
PS |
PS |
PS |
GlobalWindowAggregate |
PS |
PS |
PS |
GroupWindowAggregate |
PS |
PS |
PS |
WindowAggregate |
PS |
PS |
PS |
WindowJoin |
PS |
PS |
PS |
Deduplicate |
PS |
PS |
PS |
Expand |
PS |
PS |
PS |
Rank |
PS |
PS |
PS |
Expression List
Table 3 lists the expressions and functions supported by OmniStream.
Expression |
Function Type |
BIGINT |
VARCHAR |
NULL |
TIMESTAMP(3) |
|---|---|---|---|---|---|
* |
Scalar functions |
S |
NS |
S |
S |
+ |
Scalar functions |
S |
NS |
S |
S |
- |
Scalar functions |
S |
NS |
S |
S |
/ |
Scalar functions |
S |
NS |
S |
S |
LOWER |
Scalar functions |
NA |
S |
NA |
NA |
SPLIT_INDEX |
Scalar functions |
S |
S |
NA |
NA |
DATE_FORMAT |
Scalar functions |
NA |
NA |
NA |
S |
COUNT_CHAR |
Scalar functions |
NA |
S |
NA |
NA |
HOUR |
Scalar functions |
S |
NA |
NS |
S |
REGEX_EXTRACT |
Scalar functions |
NA |
S |
NS |
NA |