Buffer control

With compressed numeric time series, you can specify the buffer size using the compression option bc(). If not specified, it will pick a default buffer size being the usable page size of the container.

You can specify it once in a compression string. It takes on following forms:

  • bc(p) – default size if the option is unspecified. This will maximize the buffer to use 1 page only and it will not spill over into a TS large element row.
  • bc(m) -allocates a buffer to hold up a 256 rows if every variable length column has its maximum length. 256 is also the maximum number of rows cached in swingdoor compress. The buffer size is 256*rowsize. (where rowsize is the maximum size of a row being compressed).
  • bc(o) – provided for backward compatibility and gets the current buffer size and compression format.
  • bc(n) – where n is a positive number in bytes. This sets the size of the buffer to n.
  • bc(nk) – where n is a positive number in kilobytes (and k is a suffix). This sets the size of the buffer to n * 1024.
  • bc(nr) – where n is a positive number of rows (and k is a suffix). This sets the size of the buffer to n * rowsize
Note: Specifying the number of rows as part of the buffer size does not limit the number of rows that will be compressed into that buffer.

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