kuczoram opened a new pull request, #6768:
URL: https://github.com/apache/hive/pull/6768
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### What changes were proposed in this pull request?
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I propose to extend the SQL queries which are fetching the potential
compaction with an oder by CTC_TXNID. Since the TXNID is an always increasing
number, this way we can be sure that the older entries in the
COMPLETED_TXN_COMPONENTS tables are fetched first. This way we can make sure
that all tables will get into the compaction cycle at once.
Also propose to apply separate limit for the aborted txn cleaup. If the
fetch limit is smaller then the compaction candidates, the aborted txns will
never be fetched.
### Why are the changes needed?
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After [HIVE-27444](https://issues.apache.org/jira/browse/HIVE-27444), if the
number of candidates is bigger than the compactor.fetch.size value, it can
happen that the Initiator doesn't schedule all tables for compaction.
For example: we have 4 tables, which are all eligible for compaction, but
the fetch size is 2.
In the first initiator run, it will pick two of these tables. It would be
expected that during the second run of the initiator it would pick the other
two tables, so all 4 tables have been scheduled for compaction.
Since there is no ordering when selecting the tables for compaction, this
was not always the case. It could happen that some tables never got compacted.
Also if the number of candidates is bigger than the compactor.fetch.size
limit, the aborted txn candidates will never be picked up by the initiator.
Because the "remaining budget" will always be 0 in the
FindPotentialCompactionsFunction.
Set<CompactionInfo> candidates = new HashSet<>(jdbcResource.execute(new
CompactionCandidateHandler(lastChecked, fetchSize)));
int remaining = fetchSize - candidates.size();
if (collectAbortedTxns && remaining > 0) {
candidates.addAll(jdbcResource.execute(new
AbortedTxnHandler(abortedTimeThreshold, abortedThreshold, remaining)));
}
This affects only the cases when the aborted txn clean-up is done by the
compaction cycle and not just the cleaner.
### Does this PR introduce _any_ user-facing change?
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No
### How was this patch tested?
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Unit test
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