Hi John, 1. There is no "begin prepare" record, nodes acquire locks on TX keys and then transfer local TX to PREPARED state. 2. TxRecord is logged when local TX state changes to PREPARED, COMMITED or ROLLED_BACK before sending a response to what you call "coordinator" (in Ignite we use the term "near node", because the term "coordinator" is already used in another case). 3. Yes.
Hope this helps. On Wed, Aug 8, 2018 at 6:29 PM, John Wilson <sami.hailu...@gmail.com> wrote: > No they are not. I just want to understand. > > On Wednesday, August 8, 2018, Dmitriy Pavlov <dpavlov....@gmail.com> > wrote: > > > Hi John, > > > > Are these questions related to some contribution? > > > > Sincerely, > > Dmitriy Pavlov > > > > ср, 8 авг. 2018 г. в 3:18, John Wilson <sami.hailu...@gmail.com>: > > > > > Hi, > > > > > > Assume the following: > > > > > > > > > - I have a transaction coordinator and two primary nodes with 0 > backup > > > nodes. > > > - Persistence store is enabled. > > > - I'm running a transaction in pessimistic mode with serializable > > > isolation. > > > > > > I have these questions: > > > > > > 1. What exactly happens during the prepare phase? Only acquiring > locks > > > on the two primary nodes? Or do the primary nodes themselves, in > > > addition > > > to acquiring locks, write to their respective WAL a TxRecord with a > > > "begin > > > prepare" info? > > > 2. Assume locks have been acquired successfully, would the nodes > then > > > write a "prepared" TxRecord to WAL before returning a "Yes" vote to > > > coordinator? > > > 3. When the coordinator sends a commit message, would each node > write > > > the key-values to the DataRecord and a commit to the TxRecord before > > > returning to coordinator? > > > > > > > > > Overall, I'm trying to understand what happens exactly during prepare > and > > > commit phases and when the key-values involved in the transaction are > > > actually written; as well as the exact updates that are written to the > > WAL > > > files in each phase. > > > > > > appreciate your response. > > > > > > Thanks, > > > > > > -- Best regards, Ilya
