Github user afs commented on a diff in the pull request:
https://github.com/apache/jena/pull/423#discussion_r189391030
--- Diff:
jena-db/jena-dboe-transaction/src/main/java/org/apache/jena/dboe/transaction/txn/TransactionCoordinator.java
---
@@ -88,6 +89,22 @@
// See also {@code lock} which protects the datastructures during
transaction management.
private ReadWriteLock exclusivitylock = new ReentrantReadWriteLock() ;
+ // The version is the serialization point for a transaction.
+ // All transactions on the same view of the data get the same
serialization point.
+
+ // A read transaction can be promoted if writer does not start
+ // This TransactionCoordinator provides Serializable, Read-lock-free
+ // execution. With no item locking, a read can only be promoted
+ // if no writer started since the reader started or if it is "read
committed",
+ // seeing changes made since it started and comitted at the poiont of
promotion.
+
+ /* The version of the data - incremented when transaction commits.
+ * This is the version with repest to the last commited transaction.
+ * Aborts do not cause the data version to advance.
+ * This counterr never goes backwards.
--- End diff --
lang="pirate"
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