index_words, index_rel

Words-table and word-relation table. Almost self-explanatory.

Both tables are not used when basic.useMysqlFulltext extension configuration is enabled.

For the index_rel table some fields require explanation:

count

Field: count
Description: Number of occurrences on the page

first

Field: first
Description: How close to the top (low number is better)

freq

Field: freq
Description: Frequency (please see source for the calculations. This is converted from some floating point to an integer)

flags

Field

flags

Description

Bits, which describes the weight of the words:

8th bit (128) = word found in title,

7th bit (64) = word found in keywords,

6th bit (32) = word found in description,

Last 5 bits are not used yet, but if used they will enter the weight hierarchy. The result rows are ordered by this value if the "Weight/Frequency" sorting is selected. Thus results with a hit in the title, keywords or description are ranked higher in the result list.