Natvie sequence problems uncovered after OPENJPA-1376
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Key: OPENJPA-2069
URL: https://issues.apache.org/jira/browse/OPENJPA-2069
Project: OpenJPA
Issue Type: Bug
Components: jdbc, kernel
Affects Versions: 2.1.2, 2.2.0
Reporter: Albert Lee
After OPENJPA-1376 commits, it uncovered a few issues, some old and some new.
1. Backward compatibility - Previous, openjpa relies on the native sequence to
provide the next value based on the sequence's INCREMENT BY setting. Now that
openjpa manages the next sequence value and allocation size, if the db sequence
is manually created that does not match the application's increment and
allocation size, committing a new entity may result a constraint violation
exception when new sequence value is requested that crossed the allocation
boundary. This behavior is indirectly documented in the migration
consideration section in the user manual, but it would be better if this can be
handled automatically or at least to provide a compatibility option to honor
previous behavior.
2. Initial value always start with the same value (default to 1) - In
NativeJDBCSeq, the _initial, _increment and _allocate are used for the CREATE
SEQUENCE generation for SynchronizeMapping function. For existing db sequence,
next returns whatever managed by the db sequence. After the commit, next will
first return the_nextValue value in NativeJDBCSeq until _maxValue is reached,
then it go to db to get the sequence's next value, which may be ways off from
the current _maxValue.
3. _nextValue not handled proper when crossing _allocate boundary - When
NativeJDBCSeq's _nextValue exceeds the _maxValue boundary, it queries db's
sequence for the next incremental value and assign directly as the next return
value. It works for incrementBy = 1 but for some value (e.g. 3), the difference
of the before and after cross boundary values may NOT be the _increment value.
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