Replacing the [tx|long] with a thin interface which includes both the distinct transaction identifier and the timestamp of the commit record against which that tx is reading. This change will have to be propagated through the API with an eye to which methods should be sensitive to the tx identifier versus the commit point on which the tx is reading.
This change will effect at least:
- All public methods which accept a [tx|long].
- The required constructor signature for locatable resources.
- DefaultResourceLocator (which has hacks to reveal the commit time).
See https://sourceforge.net/apps/trac/bigdata/ticket/222 (term cache sharing for the same commit point).
See https://sourceforge.net/apps/trac/bigdata/ticket/431 (Use of read-only tx per query defeats cache on cluster)
See https://sourceforge.net/apps/trac/bigdata/ticket/677 (HA deadlock under UPDATE + QUERY)