Improve generating and writing out changes in Merge #1854
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This changes is part of a larger effort to improve merge performance, see delta-io#1827 ## Description This change rewrites the way modified data is written out in merge to improve performance. `writeAllChanges` now generates a dataframe containing all the updated and copied rows to write out by building a large expression that selectively applies the right merge action to each row. This replaces the previous method that relied on applying a function to individual rows. Changes: - Move `findTouchedFiles` and `writeAllchanges` to a dedicated new trait `ClassicMergeExecutor` implementing the regular merge path when `InsertOnlyMergeExecutor` is not used. - Introduce methods in `MergeOutputGeneration` to transform the merge clauses into expressions that can be applied to generate the output of the merge operation (both main data and CDC data). This change fully preserve the behavior of merge which is extensively tested in `MergeIntoSuiteBase`, `MergeIntoSQLSuite`, `MergeIntoScalaSuite`, `MergeCDCSuite`, `MergeIntoMetricsBase`, `MergeIntoNotMatchedBySourceSuite`. Closes delta-io#1854 GitOrigin-RevId: d8c8a0e9439c6710978f2ec345cb94b2b9b19e0e
scottsand-db
pushed a commit
that referenced
this pull request
Jun 26, 2023
This changes is part of a larger effort to improve merge performance, see #1827 ## Description This change rewrites the way modified data is written out in merge to improve performance. `writeAllChanges` now generates a dataframe containing all the updated and copied rows to write out by building a large expression that selectively applies the right merge action to each row. This replaces the previous method that relied on applying a function to individual rows. Changes: - Move `findTouchedFiles` and `writeAllchanges` to a dedicated new trait `ClassicMergeExecutor` implementing the regular merge path when `InsertOnlyMergeExecutor` is not used. - Introduce methods in `MergeOutputGeneration` to transform the merge clauses into expressions that can be applied to generate the output of the merge operation (both main data and CDC data). This change fully preserve the behavior of merge which is extensively tested in `MergeIntoSuiteBase`, `MergeIntoSQLSuite`, `MergeIntoScalaSuite`, `MergeCDCSuite`, `MergeIntoMetricsBase`, `MergeIntoNotMatchedBySourceSuite`. Closes #1854 GitOrigin-RevId: d8c8a0e9439c6710978f2ec345cb94b2b9b19e0e
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Note: This PR is based on #1851 and #1852 and includes the corresponding changes in the first two commits. Actual change can be seen starting from commit Improve writing changes out in Merge
This changes is part of a larger effort to improve merge performance, see #1827
Description
This change rewrites the way modified data is written out in merge to improve performance.
writeAllChangesnow generates a dataframe containing all the updated and copied rows to write out by building a large expression that selectively applies the right merge action to each row. This replaces the previous method that relied on applying a function to individual rows.Changes:
findTouchedFilesandwriteAllchangesto a dedicated new traitClassicMergeExecutorimplementing the regular merge path whenInsertOnlyMergeExecutoris not used.MergeOutputGenerationto transform the merge clauses into expressions that can be applied to generate the output of the merge operation (both main data and CDC data).How was this patch tested?
This change fully preserve the behavior of merge which is extensively tested in
MergeIntoSuiteBase,MergeIntoSQLSuite,MergeIntoScalaSuite,MergeCDCSuite,MergeIntoMetricsBase,MergeIntoNotMatchedBySourceSuite.