Github user ohadshacham commented on a diff in the pull request:
https://github.com/apache/incubator-omid/pull/46#discussion_r223975170
--- Diff:
hbase-client/src/main/java/org/apache/omid/transaction/SnapshotFilterImpl.java
---
@@ -181,22 +179,44 @@ public CommitTimestamp locateCellCommitTimestamp(long
cellStartTimestamp, long e
// 2) Then check the commit table
// If the data was written at a previous epoch, check whether
the transaction was invalidated
- Optional<CommitTimestamp> commitTimeStamp =
commitTableClient.getCommitTimestamp(cellStartTimestamp).get();
- if (commitTimeStamp.isPresent()) {
- return commitTimeStamp.get();
+ boolean invalidatedByOther = false;
+ Optional<CommitTimestamp> commitTimestampFromCT =
commitTableClient.getCommitTimestamp(cellStartTimestamp).get();
+ if (commitTimestampFromCT.isPresent()) {
+ if (isLowLatency && !commitTimestampFromCT.get().isValid())
+ invalidatedByOther = true;
+ else
+ return commitTimestampFromCT.get();
}
// 3) Read from shadow cell
- commitTimeStamp =
readCommitTimestampFromShadowCell(cellStartTimestamp, locator);
+ Optional<CommitTimestamp> commitTimeStamp =
readCommitTimestampFromShadowCell(cellStartTimestamp, locator);
if (commitTimeStamp.isPresent()) {
return commitTimeStamp.get();
}
+ // In case of LL, if found invalid ct cell, still must check
sc in stage 3 then return
+ if (invalidatedByOther) {
+ assert(!commitTimestampFromCT.get().isValid());
+ return commitTimestampFromCT.get();
+ }
+
// 4) Check the epoch and invalidate the entry
// if the data was written by a transaction from a previous
epoch (previous TSO)
- if (cellStartTimestamp < epoch) {
+ if (cellStartTimestamp < epoch || isLowLatency) {
boolean invalidated =
commitTableClient.tryInvalidateTransaction(cellStartTimestamp).get();
if (invalidated) { // Invalid commit timestamp
+
+ // If we are running lowLatency Omid, we could have
manged to invalidate a ct entry,
+ // but the committing client already wrote to shadow
cells:
--- End diff --
This can happen only in low latency mode, since in the regular mode the
client keeps the commit table entry if persisting the commit was done after the
tso lost its lease.
---
