[core] Support append read/write for MAP shared-shredding#8524
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lxy-9602 wants to merge 3 commits into
Open
[core] Support append read/write for MAP shared-shredding#8524lxy-9602 wants to merge 3 commits into
lxy-9602 wants to merge 3 commits into
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JingsongLi
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Jul 13, 2026
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| private FormatWriterFactory writerFactory() { | ||
| FormatWriterFactory factory = fileFormat.createWriterFactory(writeSchema); | ||
| return ShreddingWritePlanWriterFactories.wrapMapSharedShredding( |
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Why wrap here? Parquet will wrap this for itsself?
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MAP shared-shredding needs a MapSharedShreddingContext initialized from previous file metadata to determine the physical column count, which is difficult to handle in the format layer. That is why it is currently wrapped in AppendOnlyWriter, while Variant is wrapped inside Parquet. For consistency, would you suggest keeping this split, moving both wrappers to the writer framework, or handling both in the format layer?
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I moved the wrapping into FileFormat so Variant and MAP shared-shredding share the same write path. Could you please take another look?
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Purpose
This is a subtask of MAP shared-shredding support.
Add append table read/write support for MAP shared-shredding.
This wires MAP shared-shredding into the append write path and ORC/Parquet read path, keeps the format layer working with physical read rows, and converts them back to logical MAP rows through the shredding read plan. It also adds end-to-end coverage for basic read/write, multiple shared-shredding MAP fields, projection, data evolution, metadata recovery, null values, overflow values, and complex value types.
This PR may look somewhat large at first glance, but more than 1600 lines are tests, and the amount of production code added is relatively limited.
Tests
mvn -pl paimon-common,paimon-core -am -Pfast-build -DfailIfNoTests=false -DwildcardSuites=none -Dtest=MapSharedShreddingReadPlanTest,AppendOnlyWriterTest testmvn -pl paimon-core -am -Pfast-build -DfailIfNoTests=false -DwildcardSuites=none -Dtest=MapSharedShreddingTableTest testmvn -pl paimon-common,paimon-core -am -DskipTests spotless:applygit diff --check