Github user jinfengni commented on a diff in the pull request:
https://github.com/apache/drill/pull/376#discussion_r53068818
--- Diff:
exec/java-exec/src/main/java/org/apache/drill/exec/store/parquet/ParquetGroupScan.java
---
@@ -529,6 +549,36 @@ public long getRowCount() {
}
+
+ // Create and return a new file selection based on reading the metadata
cache file.
+ // This function also initializes a few of ParquetGroupScan's fields as
appropriate.
+ private FileSelection
+ initFromMetadataCache(DrillFileSystem fs, FileSelection selection)
throws IOException {
+ FileStatus metaRootDir = selection.getFirstPath(fs);
+ Path metaFilePath = new Path(metaRootDir.getPath(),
Metadata.METADATA_FILENAME);
+
+ // get (and set internal field) the metadata for the directory by
reading the metadata file
+ this.parquetTableMetadata = Metadata.readBlockMeta(fs,
metaFilePath.toString());
+ List<String> fileNames = Lists.newArrayList();
+ for (Metadata.ParquetFileMetadata file :
parquetTableMetadata.getFiles()) {
+ fileNames.add(file.getPath());
+ }
+ // when creating the file selection, set the selection root in the
form /a/b instead of
+ // file:/a/b. The reason is that the file names above have been
created in the form
+ // /a/b/c.parquet and the format of the selection root must match that
of the file names
+ // otherwise downstream operations such as partition pruning can break.
+ final Path metaRootPath =
Path.getPathWithoutSchemeAndAuthority(metaRootDir.getPath());
+ this.selectionRoot = metaRootPath.toString();
+
+ // Use the FileSelection constructor directly here instead of the
FileSelection.create() method
+ // because create() changes the root to include the scheme and
authority; In future, if create()
+ // is the preferred way to instantiate a file selection, we may need
to do something different...
+ FileSelection newSelection = new
FileSelection(selection.getStatuses(fs), fileNames, metaRootPath.toString());
--- End diff --
I see. Agreed that we should prioritize DRILL-4381 to address this
inconsistency.
Overall, the revised patch looks good to me.
+1
---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at infrastruct...@apache.org or file a JIRA ticket
with INFRA.
---
