Currently, we have supported nexmark sql taks from q0 to q22` in gluten flink, but some operator still need to be refined. We plan to prioritize support for stateless operators first , then add support for stateful operators.

Stateless opeators

• Connector support: kafka, pulsar, hdfs
  1. kafka [Flink][Feature]Support kafka connector bigo-sg/velox#2 , hdfs [FLINK]Support filesystem sink bigo-sg/velox#6 connectors are already implementd,need more tests and refine
  2. pulsar connector not implement yet
• Format support: json, pb, parquet, orc
  1. json format is done. pb, parquet ,orc is still not implemented.
• state management: pulsar/kafka offset, hive write part counter ...;
• checkpoint: periodic snapshot and restore
  1. interfaces have been defined
• failover:exceptions or errors need to be catched by velox, and flink controll the failover process
• support mutiple parallelism
  currently only support single pallelism
• basic data type
  1. primitive and complex types already supported: Boolean, Int, Bigint, Double, Varchar, Char, Timestamp, Decimal, Date, Row, Array, Map;
  2. types not fully supported : Timestamp with precision or timezone, e.g timestamp(n), timestamp_ltz
• experssion support
  FROM_UNIXTIME, DATE_FORMAT, UNIX_TIMESTAMP, HOUR, DAY, YEAR, TO_TIMESTAMP, PROCTIME, unix_timestamp, concat, Json_Value, TO_DATE, TO_TIMESTAMP_LTZ, SUBSTRING, CURRENT_DATE, FROM_BASE64, COALESCE, ifnull, TIMESTAMPADD, LOCALTIMESTAMP, ``

Stateful operators

• window aggregate:tumble / hop / session / cumulative
  some prs: [FLINK] Support Processing time window aggregate for nexmark q12 bigo-sg/velox#30 (processing time window)
  [FLINK]Support event time window KevinyhZou/velox#2 (event time window)
  session / cumulative window need to be implemented

• watermark
  a basic version has been implemented

• retraction semantics
  this feature is required for group aggregate and join, which has not been implemented, maybe we should introduce the rowkind just as defined in flink, combine it with row vector.

• group aggregate
  A simple version has been implemented.

• TopN rank
  A simple version has been implemented,need more tests and refine

• join: regular join / window join / interval join / temporary join
  some prs: [FLINK] Support filesystem dim table join bigo-sg/velox#16 (temporary join for nexmark q13)

• state: rockdb state / heap state
  A simple version for rocksdb state backend has been implemented: [FLINK]Support rocksdb state bigo-sg/velox#21 , yet further refinement is still needed.
  A simple version for heap state backend has been introduced in pr: [FLINK] Support Processing time window aggregate for nexmark q12 bigo-sg/velox#30

• timers: processing time timers and event time timers
  A basic version has been implemented: [FLINK] Support timer service bigo-sg/velox#29 , still need some additional work:timers serialization / stateful storage

Feature list

• Support parquet format: [FLINK] Support parquet format in hdfs writer #12202
• Support orc format: [FLINK] Support orc format in hdfs writer #12203
• Support pulsar connector: [FLINK] Support pulsar connector #12204
• Kafka / Pulsar offset state management: [FLINK] Kafka/Pulsar offset state management #12205
• Checkpoint snapshot and restore: [FLINK] Checkpoint snapshot and restore #12206
• Support multiple parallelism: [FLINK] Support multiple parallelism #12207
• Failover controll by Flink: [FLINK] Failover controll by flink #12208
• Data type support: timestamp with precision and timezone: [FLINK] Support timestamp with precision and timezone #12209
• Expressions support: [FLINK] Support regular expressions #12210