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https://issues.apache.org/jira/browse/DRILL-4905?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15530256#comment-15530256
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ASF GitHub Bot commented on DRILL-4905:
---------------------------------------
Github user jinfengni commented on a diff in the pull request:
https://github.com/apache/drill/pull/597#discussion_r80968605
--- Diff:
exec/java-exec/src/main/java/org/apache/drill/exec/ExecConstants.java ---
@@ -125,13 +125,14 @@
String PARQUET_WRITER_ENABLE_DICTIONARY_ENCODING =
"store.parquet.enable_dictionary_encoding";
OptionValidator PARQUET_WRITER_ENABLE_DICTIONARY_ENCODING_VALIDATOR =
new BooleanValidator(
PARQUET_WRITER_ENABLE_DICTIONARY_ENCODING, false);
-
String PARQUET_VECTOR_FILL_THRESHOLD =
"store.parquet.vector_fill_threshold";
OptionValidator PARQUET_VECTOR_FILL_THRESHOLD_VALIDATOR = new
PositiveLongValidator(PARQUET_VECTOR_FILL_THRESHOLD, 99l, 85l);
String PARQUET_VECTOR_FILL_CHECK_THRESHOLD =
"store.parquet.vector_fill_check_threshold";
OptionValidator PARQUET_VECTOR_FILL_CHECK_THRESHOLD_VALIDATOR = new
PositiveLongValidator(PARQUET_VECTOR_FILL_CHECK_THRESHOLD, 100l, 10l);
String PARQUET_NEW_RECORD_READER = "store.parquet.use_new_reader";
OptionValidator PARQUET_RECORD_READER_IMPLEMENTATION_VALIDATOR = new
BooleanValidator(PARQUET_NEW_RECORD_READER, false);
+ String PARQUET_RECORD_BATCH_SIZE = "store.parquet.record_batch_size";
+ OptionValidator PARQUET_RECORD_BATCH_SIZE_VALIDATOR = new
LongValidator(PARQUET_RECORD_BATCH_SIZE, 256*1024);
--- End diff --
If you want to specify the maximum of allowed batch_size, you probably have
to use PositiveLongValidator, which will allow u to specify max.
> Push down the LIMIT to the parquet reader scan to limit the numbers of
> records read
> -----------------------------------------------------------------------------------
>
> Key: DRILL-4905
> URL: https://issues.apache.org/jira/browse/DRILL-4905
> Project: Apache Drill
> Issue Type: Bug
> Components: Storage - Parquet
> Affects Versions: 1.8.0
> Reporter: Padma Penumarthy
> Assignee: Padma Penumarthy
> Fix For: 1.9.0
>
>
> Limit the number of records read from disk by pushing down the limit to
> parquet reader.
> For queries like
> select * from <table> limit N;
> where N < size of Parquet row group, we are reading 32K/64k rows or entire
> row group. This needs to be optimized to read only N rows.
>
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