HDDS-11714. resetDeletedBlockRetryCount with --all may fail and can cause long db lock in large cluster #7665
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nandakumar131
requested changes
Jan 10, 2025
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| @Override | ||
| public List<DeletedBlocksTransaction> getFailedTransactionsBatch( | ||
| int batchSize, long startTxId) throws IOException { | ||
| List<DeletedBlocksTransaction> failedTXs = new ArrayList<>(); | ||
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| lock.lock(); | ||
| try { | ||
| try ( | ||
| TableIterator<Long, ? extends Table.KeyValue<Long, DeletedBlocksTransaction>> iter = | ||
| deletedBlockLogStateManager.getReadOnlyIterator()) { | ||
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| iter.seek(startTxId); | ||
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| while (iter.hasNext() && failedTXs.size() < batchSize) { | ||
| DeletedBlocksTransaction delTX = iter.next().getValue(); | ||
| if (delTX.getCount() == -1) { | ||
| failedTXs.add(delTX); | ||
| } | ||
| } | ||
| } | ||
| } finally { | ||
| lock.unlock(); | ||
| } | ||
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| return failedTXs; | ||
| } | ||
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There was a problem hiding this comment.
Why do we need this additional method? The same thing can be achieved with the existing getFailedTransactions method.
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| } while (!batch.isEmpty()); | ||
| } else { | ||
| // Process txIDs provided by the user in batches |
There was a problem hiding this comment.
The user provided list of txIDs reaches SCM via RPC call, so it's ok to process this in single go.
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What changes were proposed in this pull request?
In case of resetDeletedBlockRetryCount with --all option, scm takes lock and tries to get all the transaction with max retry and then updates DB with 0 count. In some large scale env this count can be huge which can lead to multiple problem.
i) Lock can lead to block all other normal operation.
ii) Since message is passed through ratis, which will fail because of size.
Instead of doing like above we should do this operation in batches to avoid long lock and ratis message size failure.
What is the link to the Apache JIRA
https://issues.apache.org/jira/browse/HDDS-11714
How was this patch tested?
Tested Manually.