Major Description
For local indexes, we'll want to continue to process updates on the server-side. After PHOENIX-4278, updates even for local indexes are occurring on the client-side. The reason is that we know the updates to the index table will be a local write and we can generate the write on the server side. Having a separate RPC and sending the updates across the wire would be tremendously inefficient. On top of that, we need the region boundary information which we have already in the coprocessor, but would need to retrieve it on the client side (with a likely race condition too if a split occurs after we retrieve it).
To fix this, we need to modify PhoenixTxnIndexMutationGenerator such that it can be use on the server-side as well. The main change will be to change this method signature to pass through an IndexMaintainer instead of a PTable (which isn't available on the server-side):
public List<Mutation> getIndexUpdates(final PTable table, PTable index, List<Mutation> dataMutations) throws IOException, SQLException {
I think this can be changed to the following instead and be used both client and server side:
public List<Mutation> getIndexUpdates(final IndexMaintainer maintainer, byte[] dataTableName, List<Mutation> dataMutations) throws IOException, SQLException {
We can tweak the code that makes PhoenixTransactionalIndexer a noop for clients >= 4.14 to have it execute if the index is a local index. The one downside is that if there's a mix of local and global indexes on the same table, the index update calculation will be done twice. I think having a mix of index types would be rare, though, and we should advise against it.
There's also this code in UngroupedAggregateRegionObserver which needs to be updated to write shadow cells for Omid:
} else if (buildLocalIndex) {
for (IndexMaintainer maintainer : indexMaintainers) {
if (!results.isEmpty()) {
result.getKey(ptr);
ValueGetter valueGetter =
maintainer.createGetterFromKeyValues(
ImmutableBytesPtr.copyBytesIfNecessary(ptr),
results);
Put put = maintainer.buildUpdateMutation(kvBuilder,
valueGetter, ptr, results.get(0).getTimestamp(),
env.getRegion().getRegionInfo().getStartKey(),
env.getRegion().getRegionInfo().getEndKey());
indexMutations.add(put);
}
}
result.setKeyValues(results);
This is the code that builds a local index initially (unlike the global index code path which executes an UPSERT SELECT on the client side to do this initial population).