alamb opened a new issue, #10546:
URL: https://github.com/apache/datafusion/issues/10546

   ### Is your feature request related to a problem or challenge?
   
   It is common in databases and other analytic system to have additional 
external "indexes" (perhaps stored in the "metadata catalog", perhaps stored 
alongside the data files, perhaps embedded in the files, perhaps elsewhere)
   
   These indexes are used to speed up queries by "pruning" the files -- 
specifically evaluating a predicate on the index and then only reading files / 
portions of files that would pass the filters in the query
   
   Implementing such a index requires several three steps:
   1. Creating / maintaining the actual index
   2. A way to evaluate the index against the query predicate
   3. A way to use the index to filter the files that need to be read
   
   DataFusion has code already to do 2 (PruningPredicate) and 3 (ParquetExec) 
but I am not sure how obvious it is to put togeher
   
   DataFusion actually also has basic support for 1 (e.g. the 
ListingTableProvider reads statistics and prunes based on their statistics)
   
   We have some version of this in InfluxDB today, and we are in the process of 
extending it. However, I think the usecase is much more general and could be 
useful for other systems as well (e.g. full text indexes across parquet, for 
example). 
   
   I also think creating an  example will help motivate the work from @NGA-TRAN 
 in https://github.com/apache/datafusion/issues/10453 and myself in 
https://github.com/apache/datafusion/issues/9929
   
   
   ### Describe the solution you'd like
   
   _No response_
   
   ### Describe alternatives you've considered
   
   _No response_
   
   ### Additional context
   
   _No response_


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