Hello,
We have a requirement to determine whether a PUT will create a new row or
update an existing one. I looked at using preBatchMutate in a co-processor and
have the code below.
Few things I need to ask:
1) Is there a more efficient way of doing this?
2) Will region.getClosestRowBefore() add additional IO to go to disk? or will
the row be in memory since the row lock was already acquired before
preBatchMutate is called?
3) Will region.getClosestRowBefore() always give the correct result? Or are
there scenarios where the previous state will not be visible?
@Override
public void preBatchMutate(ObserverContext<RegionCoprocessorEnvironment> c,
MiniBatchOperationInProgress<Mutation> miniBatchOp) throws IOException {
for (int i = 0; i < miniBatchOp.size(); i++) {
Mutation operation = miniBatchOp.getOperation(i);
byte[] rowKey = operation.getRow();
NavigableMap<byte[], List<Cell>> familyCellMap =
operation.getFamilyCellMap();
for (Entry<byte[], List<Cell>> entry : familyCellMap.entrySet()) {
for (Iterator<Cell> iterator = entry.getValue().iterator();
iterator.hasNext();) {
Cell cell = iterator.next();
byte[] family = CellUtil.cloneFamily(cell);
Result closestRowBefore =
c.getEnvironment().getRegion().getClosestRowBefore(rowKey, family);
// closestRowBefore would return null if there is not
record for the rowKey and family
if (closestRowBefore != null) {
// PUT is doing an update for the given rowKey, family
} else {
// PUT is doing an insert for the given rowKey, family
}
}
}
}
super.preBatchMutate(c, miniBatchOp);
}
Thanks
Venu Bora
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