bitcoin/bitcoin — pull request #2168 by sipa (2013-01-11 01:56:30+00:00)
Title: Add optional transaction index to databases

By specifying -txindex when initializing the database, a txid-to-diskpos index is maintained in the blktree database. This database is used to help answering getrawtransaction() RPC queries, when enabled.

Changing the -txindex value requires a -reindex; the client will abort at startup if the database and the specified -txindex mismatch.