export-parameter-if-dir-exists.md
What to do if directory
already exists, one of:
-
fail
(default) -
overwrite
: replace the entire directory -
append
: export new files into the existing directory with a prepended hash that identifies all files in the exported batch -
appendNoHash
: export new files into the existing directory without a prepended hash; with this option, Vertica cannot clean up partial exports
If you specify overwrite
for an export to an object store, the existing directory is deleted recursively at the beginning of the operation and is not restored if the operation fails. Be careful not to export to a directory containing data you want to keep. For an export to a Linux file system or HDFS, the directory is only overwritten if the export succeeds.
Do not do concurrent exports to the same directory. In particular, if you do so with a value of overwrite
, all operations appear to succeed, but the results are incorrect.
When using append
, be careful to use the same table schema. Otherwise, queries of external tables using this data path could fail.