Disk space needed for parallel indexing

• Article Type: General
• Product: Aleph
• Product Version: 17.01

Description:
We wish to implement parallel indexing, and understand that the data itself is not replicated, but only index pointers to the data. How should we calculate the amount of disk space necessary for these additional index pointers? Is there a method to do this? We have read the Parallel Indexing documentation, but still do not have a good idea of how to go about calculating needed disk space.

Resolution:
The index pointers take no space. The Oracle space required in the parallel library will be the space required for the znn index tables and znn_idx Oracle indexes which are being built. You can use util a/17/11/2 to check the space which each table and Oracle index are currently occupying.

(The first column in util a/17/11/2 has the number of bytes the table/index is taking, in Kilobytes. Thus, if you see:

BYTES/1024 BLOCKS EXTENTS INITIAL_EXTENT NEXT_EXTENT
---------- ---------- ---------- -------------- -----------
5529600 691200 27 1006632960 209715200

this table is taking 5.5 gigabytes.

The size of the tables/indexes in the parallel library could be greater or less, depending on what fields are being sent to what indexes in tab11_ind, tab11_acc, or tab11_word in the parallel library (compared to the current library).