[ 
https://issues.apache.org/jira/browse/SPARK-31962?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
 ]

Christopher Highman updated SPARK-31962:
----------------------------------------
    Description: 
When using structured streaming with a FileDataSource, I've encountered a 
number of occasions where I want to be able to stream from a folder containing 
any number of historical files in CSV format.  When I start reading from a 
folder, however, I might only care about files that were created after a 
certain time.
{code:java}
spark.readStream
     .option("header", "true")
     .option("delimiter", "\t")
     .format("csv")
     .load("/mnt/Deltas")
{code}
In 
[https://github.com/apache/spark/blob/f3771c6b47d0b3aef10b86586289a1f675c7cfe2/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/InMemoryFileIndex.scala],
 there is a method, _listLeafFiles,_ which builds _FileStatus_ objects 
containing an implicit _modificationDate_ property.  We may already iterate the 
resulting files if a filter is applied to the path.  In this case, its trivial 
to do a primitive comparison against _modificationDate_ and a date specified 
from an option.  Without the filter specified, we would be expending less 
effort than if the filter were applied by itself since we are comparing 
primitives.  

Having the ability to provide an option where specifying a timestamp when 
loading files from a path would minimize complexity for consumers who leverage 
the ability to load files or do structured streaming from a folder path but do 
not have an interest in reading what could be thousands of files that are not 
relevant.

One example to could be "_filesModifiedAfterDate_" accepting a UTC datetime 
like below.
{code:java}
spark.readStream
     .option("header", "true")
     .option("delimiter", "\t")
     .option("filesModifiedAfterDate", "2020-05-01T12:00:00")
     .format("csv")
     .load("/mnt/Deltas")
{code}
If this option is specified, the expected behavior would be that files within 
the _"/mnt/Deltas/"_ path must have been created at or later than the specified 
time in order to be consumed for purposes of reading files from a folder path 
or via structured streaming.

 I have unit tests passing under _CSVSuite_ and _FileIndexSuite_ in the 
_spark.sql.execution.datasources_ package.

  was:
When using structured streaming with a FileDataSource, I've encountered a 
number of occasions where I want to be able to stream from a folder containing 
any number of historical files in CSV format.  When I start reading from a 
folder, however, I might only care about files that were created after a 
certain time.
{code:java}
spark.readStream
     .option("header", "true")
     .option("delimiter", "\t")
     .format("csv")
     .load("/mnt/Deltas")
{code}
In 
[https://github.com/apache/spark/blob/f3771c6b47d0b3aef10b86586289a1f675c7cfe2/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/InMemoryFileIndex.scala],
 there is a method, _listLeafFiles,_ which builds _FileStatus_ objects 
containing an implicit _modificationDate_ property.  We may already iterate the 
resulting files if a filter is applied to the path.  In this case, its trivial 
to do a primitive comparison against modificationDate and a date specified from 
an option.  Without the filter specified, we would be expending less effort 
than if the filter were applied by itself since we are comparing primitives.  

Having the ability to provide an option where specifying a timestamp when 
loading files from a path would minimize complexity for consumers who leverage 
the ability to load files or do structured streaming from a folder path but do 
not have an interest in reading what could be thousands of files that are not 
relevant.

One example to could be "_filesModifiedAfterDate_" accepting a UTC datetime 
like below.
{code:java}
spark.readStream
     .option("header", "true")
     .option("delimiter", "\t")
     .option("filesModifiedAfterDate", "2020-05-01T12:00:00")
     .format("csv")
     .load("/mnt/Deltas")
{code}
If this option is specified, the expected behavior would be that files within 
the _"/mnt/Deltas/"_ path must have been created at or later than the specified 
time in order to be consumed for purposes of reading files from a folder path 
or via structured streaming.

 I have unit tests passing under _CSVSuite_ and _FileIndexSuite_ in the 
_spark.sql.execution.datasources_ package.


> Provide option to load files after a specified date when reading from a 
> folder path
> -----------------------------------------------------------------------------------
>
>                 Key: SPARK-31962
>                 URL: https://issues.apache.org/jira/browse/SPARK-31962
>             Project: Spark
>          Issue Type: Improvement
>          Components: SQL, Structured Streaming
>    Affects Versions: 3.1.0
>            Reporter: Christopher Highman
>            Priority: Minor
>
> When using structured streaming with a FileDataSource, I've encountered a 
> number of occasions where I want to be able to stream from a folder 
> containing any number of historical files in CSV format.  When I start 
> reading from a folder, however, I might only care about files that were 
> created after a certain time.
> {code:java}
> spark.readStream
>      .option("header", "true")
>      .option("delimiter", "\t")
>      .format("csv")
>      .load("/mnt/Deltas")
> {code}
> In 
> [https://github.com/apache/spark/blob/f3771c6b47d0b3aef10b86586289a1f675c7cfe2/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/InMemoryFileIndex.scala],
>  there is a method, _listLeafFiles,_ which builds _FileStatus_ objects 
> containing an implicit _modificationDate_ property.  We may already iterate 
> the resulting files if a filter is applied to the path.  In this case, its 
> trivial to do a primitive comparison against _modificationDate_ and a date 
> specified from an option.  Without the filter specified, we would be 
> expending less effort than if the filter were applied by itself since we are 
> comparing primitives.  
> Having the ability to provide an option where specifying a timestamp when 
> loading files from a path would minimize complexity for consumers who 
> leverage the ability to load files or do structured streaming from a folder 
> path but do not have an interest in reading what could be thousands of files 
> that are not relevant.
> One example to could be "_filesModifiedAfterDate_" accepting a UTC datetime 
> like below.
> {code:java}
> spark.readStream
>      .option("header", "true")
>      .option("delimiter", "\t")
>      .option("filesModifiedAfterDate", "2020-05-01T12:00:00")
>      .format("csv")
>      .load("/mnt/Deltas")
> {code}
> If this option is specified, the expected behavior would be that files within 
> the _"/mnt/Deltas/"_ path must have been created at or later than the 
> specified time in order to be consumed for purposes of reading files from a 
> folder path or via structured streaming.
>  I have unit tests passing under _CSVSuite_ and _FileIndexSuite_ in the 
> _spark.sql.execution.datasources_ package.



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