tldr: Aries
Part of the tldr series , which summarizes papers I'm currently reading. Inspired by the morning paper . tldr: ARIES - A Transaction Recovery Method [1992] Mohan et. al *With Concurrency Control and Recovery, by Franklin and an example from http://db.csail.mit.edu/6.830/notes.php ARIES is a protocol for DBMS recovery based on WAL. (For a review of the basics of WAL, you can take a look here .) This blog post will go over ARIES with an example and explanations along the way. Example This is the example we'll be following: CP = checkpoint, Flush = flush to disk, W = write Assume the following is the log right before the crash: SOT = start of transaction, EOT = end of transaction, UP = update (In this example, each data item is on a different page. Treat them synonymously for simplicity.) Data Structures Transaction Table The transaction table stores data about ongoing transactions. One of the pieces of data is lastLSN , which is the LSN of the