Jun Zhang created FLINK-31338:
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             Summary: support  infer parallelism for flink table store
                 Key: FLINK-31338
                 URL: https://issues.apache.org/jira/browse/FLINK-31338
             Project: Flink
          Issue Type: Improvement
          Components: Table Store
    Affects Versions: table-store-0.3.0
            Reporter: Jun Zhang
             Fix For: table-store-0.4.0


When using flink  to query the fts table, we can config the scan parallelism by 
set the scan.parallelism, but the user may do not know how much parallelism 
should be used,  setting a too large parallelism will cause resource waste, 
setting the parallelism too small will cause the query to be slow, so we can 
add parallelism infer.

The function is enabled by default. the parallelism is equal to the number of 
read splits. Of course, the user can manually turn off the infer function. In 
order to prevent too many datafiles from causing excessive parallelism, we also 
set a max infer parallelism. When the infer parallelism exceeds the setting, 
use the max parallelism.

In addition, we also need to compare with the limit in the select query 
statement to get a more appropriate parallelism in the case of limit pushdown, 
for example we have a sql select * from table limit 1, and finally we infer the 
parallelism is 10, but we only one parallel is needed , besause we only need 
one data .



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