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Posted to issues@hbase.apache.org by "rstest (Jira)" <ji...@apache.org> on 2026/01/28 09:44:00 UTC
[jira] [Updated] (HBASE-29857) BucketCache fails to start when persistence file was written with empty cache
[ https://issues.apache.org/jira/browse/HBASE-29857?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
rstest updated HBASE-29857:
---------------------------
Description:
When a RegionServer with BucketCache persistence enabled is restarted, if the BucketCache was empty at shutdown time, the new RegionServer fails to start with a `NullPointerException` in `BucketCache.parsePB()`.
The bug is in the interaction between `BucketProtoUtils.serializeAsPB()` and `BucketCache.retrieveChunkedBackingMap()`:
1. **During shutdown with empty cache**: When `backingMap.size() == 0`, `serializeAsPB()` writes `numChunks = 0` to the persistence file, but the loop that writes `BucketCacheEntry` objects never executes (because there are no entries to iterate). This means **no BucketCacheEntry is written to the file**.
2. **During startup**: `retrieveChunkedBackingMap()` reads `numChunks = 0` from the file, but still attempts to read the first chunk using `parseDelimitedFrom()`. Since no `BucketCacheEntry` was written, `parseDelimitedFrom()` returns `null`.
3. **NPE occurs**: The null `firstChunk` is passed to `parsePB()`, which calls `firstChunk.getDeserializersMap()` on the null object, causing NPE.
Use the attached test can reproduce this bug.
was:
When a RegionServer with BucketCache persistence enabled is restarted, if the BucketCache was empty at shutdown time, the new RegionServer fails to start with a `NullPointerException` in `BucketCache.parsePB()`.
> BucketCache fails to start when persistence file was written with empty cache
> -----------------------------------------------------------------------------
>
> Key: HBASE-29857
> URL: https://issues.apache.org/jira/browse/HBASE-29857
> Project: HBase
> Issue Type: Bug
> Components: regionserver
> Affects Versions: 2.6.3
> Reporter: rstest
> Priority: Major
>
> When a RegionServer with BucketCache persistence enabled is restarted, if the BucketCache was empty at shutdown time, the new RegionServer fails to start with a `NullPointerException` in `BucketCache.parsePB()`.
>
> The bug is in the interaction between `BucketProtoUtils.serializeAsPB()` and `BucketCache.retrieveChunkedBackingMap()`:
> 1. **During shutdown with empty cache**: When `backingMap.size() == 0`, `serializeAsPB()` writes `numChunks = 0` to the persistence file, but the loop that writes `BucketCacheEntry` objects never executes (because there are no entries to iterate). This means **no BucketCacheEntry is written to the file**.
> 2. **During startup**: `retrieveChunkedBackingMap()` reads `numChunks = 0` from the file, but still attempts to read the first chunk using `parseDelimitedFrom()`. Since no `BucketCacheEntry` was written, `parseDelimitedFrom()` returns `null`.
> 3. **NPE occurs**: The null `firstChunk` is passed to `parsePB()`, which calls `firstChunk.getDeserializersMap()` on the null object, causing NPE.
> Use the attached test can reproduce this bug.
>
>
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