AnishMahto opened a new pull request, #55969:
URL: https://github.com/apache/spark/pull/55969

   Approved AutoCDC SPIP: 
https://lists.apache.org/thread/j6sj9wo9odgdpgzlxtvhoy7szs0jplf7
   
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   This is a stacked PR. Review incremental diff here: 
https://github.com/AnishMahto/spark/compare/SPARK-56838-introduce-ChangeArgs...SPARK-56856-SCD1-microbatch-deduplication
   
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   **Preamble:**
   
   The SCD type 1 flow is a foreachBatch streaming query on an input 
change-data-feed, and is responsible for reconciling the incoming change data 
onto some target table that follows SCD1 replication semantics.
   
   SCD1 flows also maintain an "auxiliary" table to keep track of 
early-arriving out-of-order received events state. Each microbatch will need to 
reconcile against this auxiliary table as well, and update the auxiliary 
table's state appropriately for future microbatches.
   
   
   **Microbatch Deduplication:**
   
   The first step of microbatch reconciliation for SCD1 is deduplicating the 
microbatch such that there is a single row per key. 
   
   Since SCD1 is only concerned with maintaining latest state per key from the 
change data source, within a microbatch we only care about the row with the 
latest sequencing per key - drop all other rows for that same key.


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