Copy from local to HP Vertica
In the document, it is saying “copy from local” can’t do parallel load. What does this really mean?
In the client side, can multithreads run "copy table1 from local fileName " at the same time? For example:
thread 1: copy table1 from local fileName1
thread 2: copy table1 from local fileName2
thread 3: copy table1 from local filename3
if above scenario is ok, does above strategy runs faster than one thread, for example:
thread1: copy table1 from local fileName1,fileName2,fileName3
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Comments
From the documents:
By default, the initiator node for a COPY statement using the default parser uses parallel parsing for each significant (1GB and over) load file. Parsing load files is a multi-threaded operation that start at different offsets in the file. In addition, you can create multiple parallel load streams, as this section describes. Creating parallel load streams can significantly increase performance and use resources more efficiently.
Found here
In my experience it's not a problem to import multiple files into the same tables. As long as you are not doing multiple copy statements on the same file simultaneously there shouldn't be any problems.