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https://issues.apache.org/jira/browse/IGNITE-18497?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Denis Chudov updated IGNITE-18497:
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Fix Version/s: 3.0.0-beta2
> Read only get returns a first one value getting from primary index
> ------------------------------------------------------------------
>
> Key: IGNITE-18497
> URL: https://issues.apache.org/jira/browse/IGNITE-18497
> Project: Ignite
> Issue Type: Bug
> Reporter: Vladislav Pyatkov
> Assignee: Denis Chudov
> Priority: Major
> Labels: ignite-3
> Fix For: 3.0.0-beta2
>
> Time Spent: 10m
> Remaining Estimate: 0h
>
> *Motivation*
> Indexes store all value associated with different versions of one entry. By
> the reason, for getting value by primary index, we scan the index with the
> specific key. If we insert, delete and again insert an entry with the same
> indexed fields, the entry can resolve in versioned storage for different row
> ids. But only one resolution should return not empty value, because only one
> entry can exist by the unique index.
> *Implementation notes*
> The resolution happens here:
> {code:java}
> PartitionReplicaListener#resolveRowByPk(BinaryRow, HybridTimestamp){code}
> But in case when a read result is resolved to null, need to continue the
> loop, because the actual value associated with the key may be removed (this
> is the null value, but it is not actual) and inserted again.
>
> h3. upd 1:
> # Seems that it's rather simple in case of primary index (and given ticket
> is about primary index) because keys are unmodifiable, so it's only possible
> to have multiple entries for particular search key only in case of creation->
> removal -> creation. That means that we can have one and only one non empty
> readResult for any read timestamp for the given key. Which in turn means that
> if we found non empty readResult during PK index iteration we can proceed
> with readResult resolution and stop the iteration, oterwise, in case of empty
> read result we should continue the iteration as Vlad told. So basically we
> should add
> {code:java}
> if (readResult.isEmpty()) {continue;}{code}
> after
> {code:java}
> ReadResult readResult = mvDataStorage.read(rowId, ts);{code}
> # We should probably fix PartitionReplicaListener#resolveReadResult instead
> of returning null in case of null readResult we should complete future with
> null.
> {code:java}
> private CompletableFuture<BinaryRow> resolveReadResult(
> ReadResult readResult,
> @Nullable UUID txId,
> @Nullable HybridTimestamp timestamp,
> @Nullable Supplier<BinaryRow> lastCommitted
> ) {
> if (readResult == null) {
> return null;
> {code}
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