[HBASE-16992] The usage of mutation from CP is weird.

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 1.3.0, 1.4.0, 2.0.0
• Fix Version/s: 1.4.0, 2.0.0
• Hadoop Flags: Reviewed
• Assignee: Chia-Ping Tsai
• Reporter: Chia-Ping Tsai
• Created: 02/Nov/16 10:16
• Updated: 07/Nov/16 23:36
• Resolved: 07/Nov/16 17:57

Description

HRegion#doMiniBatchMutate

Mutation cpMutation = cpMutations[j];
Map<byte[], List<Cell>> cpFamilyMap = cpMutation.getFamilyCellMap();
checkAndPrepareMutation(cpMutation, replay, cpFamilyMap, now);
 // Acquire row locks. If not, the whole batch will fail.
acquiredRowLocks.add(getRowLockInternal(cpMutation.getRow(), true));
if (cpMutation.getDurability() == Durability.SKIP_WAL) {
  recordMutationWithoutWal(cpFamilyMap);
}
// Returned mutations from coprocessor correspond to the Mutation at index i. We can
 // directly add the cells from those mutations to the familyMaps of this mutation.
mergeFamilyMaps(familyMaps[i], cpFamilyMap); // will get added to the memstore later

1. Does the returned mutation from coprocessor have the same row as the corresponded mutation? If so, the acquiredRowLocks() can be saved. If not, the corresponded mutation may maintain the cells with different row due to mergeFamilyMaps().
2. Is returned mutation's durability useful? If so, we should deal with the different durabilities before mergeFamilyMaps(). If not, the recordMutationWithoutWal can be saved.
3. If both the returned mutation and corresponded mutation have Durability.SKIP_WAL, the recordMutationWithoutWal() may record the duplicate cells due to mergeFamilyMaps().

Any comment? Thanks.

Issue Links

• is related to: HBASE-15600 Add provision for adding mutations to memstore or able to write to same region in batchMutate coprocessor hooks