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The purpose of an inverted index is to allow fast full-text searches, at a cost of increased processing when a document is added to the database. The inverted file may be the database file itself, rather than its index.
Reverse-key indexes reduce "hot spots" in indexes, especially primary key indexes, by reversing the bytes of the leaf blocks and thus eliminating the contention for leaf blocks across instances.
An inverted index is a mapping of words to their location in a set of documents. Most modern search engines utilize some form of an inverted index to process user-submitted queries. In its most basic form, an inverted index is a simple hash table which maps words in the documents to some sort of document identifier.
This type of index is called an inverted index, namely because it is an inversion of the forward index.
I just learned about reverse indexing. The wikipedia page says that
In database management systems, a reverse key index strategy reverses the key value before entering it in the index.1 E.g., the value 24538 becomes 83542 in the index. Reversing the key value is particularly useful for indexing data such as sequence numbers, where each new key value is greater than the prior value, i.e., values monotonically increase. Reverse key indexes have become particularly important in high volume transaction processing systems because they reduce contention for index blocks.
Why is reversing the key value useful for indexing sequence numbers? Also, why do reverse indexes help reduce contention for index blocks in high volume systems? In short: what is the point of reverse indexing?
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