To estimate TEXT index main store size, use this formula:
Number of bytes = (15+L)*U + U*PAGESIZE * R + T
where:
L = average term length for the vocabulary
U = number of unique terms in the vocabulary
R = number of millions of documents
T = total number of all terms in all documents
The temporary space required in bytes for the TEXT index is (M+20)* T, where:
M = the maximum term length for the text configuration in bytes
The temporary space required is subject to compressibility
of the sort data.
