How does the format of my data affect queries?

Answer: The format of the documents (plain ASCII text, HTML, or Microsoft Word) should make no difference to query speed. The documents are filtered to plain text at indexing time, not query time.

The cleanliness of the data makes a difference. Spell-checked and subedited text for publication tends to have a much smaller total vocabulary (and therefore size of the index table) than informal text such as email, which contains spelling errors and abbreviations. For a given index memory setting, the extra text takes up memory, creates more fragmented rows, and adversely affects query response time.