http://orientdb.com/docs/2.1/Transactions.html
Check the isolation part. I might not be precise about "reads". The COMMANDS are executed out of TX scope. The point is that when a record is "fetched" from DB you will get lastly commited version of that record, every time this "fetch" is requested and it does not matter if there is or isn't a transaction. However, as far as my observations go, accessing the same record via Graph API multiple times (Graph.getVertex(id)) in a single transaction does not lead to refetching/querying DB for that record again. (Actually I am not sure about that, but I am sure that changes performed on this record in a single TX are preserved, so it leads me to a conclusion, that you're working with a local cached copy of that record) So by using this (imho) very limited Graph API exclusively you will basically achieve a REPEATABLE READS behavior, but in reality it isn't, because it does not work with other retrieval methods (quries/commands). This is at least my understanding of the documentation. Dne úterý 15. září 2015 21:44:14 UTC+2 Alan47 napsal(a): > > Hi, > thanks for the response, much appreciated! The fact that OrientDB executes > reads exclusively outside of transactions is new to me, and rather > surprising. Is this documented anywhere? > > We are running OrientDB in plocal mode exclusively, and according to a doc > page I read today the default isolation level is serializable, which is > more than sufficient. > > If reads do indeed not require a transaction, i.e. a OrientGraphNoTx, then > it would be interesting how that class is intended to behave under > concurrent access, as the documentation refers to "one transaction per > thread". That would imply that if there is no transaction, we are free to > execute parallel reads on the same graph instance, but thats just my > interpretation. > > You are absolutely correct about the threat of future problems when > relying on undocumented behaviour. This is exactly why I ask this question, > in fact our application is running fine right now with concurrent reads on > the same graph. > > -- --- You received this message because you are subscribed to the Google Groups "OrientDB" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
