Do filter push down when reading from views #160
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/gcbrun |
davidrabinowitz
requested changes
Apr 24, 2020
| def getNumBytes(tableDefinition: TableDefinition): Long = { | ||
| val tableType = tableDefinition.getType | ||
| if (options.viewsEnabled && TableDefinition.Type.VIEW == tableType) { | ||
| 0 |
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Please replace the value with the default: sqlContext.conf.defaultSizeInBytes (taken from here)
Based on the documentation having a size of 0 may have side effects.
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sqlContext.conf is not accessible outside of org.apache.spark.sql so I had to use sqlContext.sparkSession.sessionState.conf.defaultSizeInBytes instead
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Hi @diggerk , thanks for the contribution! Can you please have a look at the comment above? |
Using 0 as Spark relation size estimate may lead to spark broadcasting the relation that potentially represets a large table
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Hi @davidrabinowitz , thanks for the catch, I fixed that. |
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/gcbrun |
davidrabinowitz
approved these changes
Apr 24, 2020
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Here's a fix for filter push down for views. I've moved temp table creation to the moment when "buildScan" is invoked. The defaultTableDefinition type is changed to "TableDefinition" and a separate method "getNumBytes" is created to calculate the size of the table. The "getNumBytes" returns zero bytes for views, and that should be fine as the important part is that the connector calculates the number of partitions after the temp table is generated and by that time the getNumBytes will be called on the temp table, not the view.