Main differents between encoding and compression

eli_revach

Hi , What is the main different between encoding and compression ? i know Vertica is able to work on top of encoding data but not on top of compress data its need first to be decompress Did encoding is a stage before compression or its type of compression ?

[Deleted User]

Hi Eli: Conceptually, encoding depends on the data type of the data being encoded, and compression treats a compressed block as opaque / doesn't really care what's in it. That's why Vertica operates on encoded data but not compressed data. Encoding is a separate step that's always performed before compression.

eli_revach

Hi Adam , So the data in a column with RLE encoding is both and encoded and compress or it just encoded ?

[Deleted User]

Hi Eli, In that case, when Vertica writes the column to disk, it is both encoded and compressed.

tolgahan

Hi aseering,

 

Thanks for reply, we have felt a bit confused about your answer. So can we say, encoded column automatically compressed before it written to the disk? Or it is a feature for only RLE encoding type?

 

And if it is automatically compressing then could we disable that by any parameter or manual operation. Because we thought it would be fast to read uncompressed data from disk in proportion to compressed data. (Please assume that we have enough space in db)

 

Thanks a lot.