[OAK-9905] File Store GC leaves the Store in an unconsistent state

• Type: Bug
• Status: Resolved
• Priority: Blocker
• Resolution: Not A Problem
• Affects Version/s: 1.42.0
• Component/s: segment-tar, segmentmk
• Assignee: Unassigned
• Reporter: Piercarlo Slavazza
• Created: 18/Aug/22 07:56
• Updated: 15/Sep/22 12:04
• Resolved: 15/Sep/22 12:04

Description

I created a File Store using Jackrabbit Oak v. 1.42.0.

I added some nodes, and then deleted some of them.

I then inspect the "history" of the store, using the very same code used by oak-run - but executed in my application (no OSGi):

Iterator<RevisionHistory.HistoryElement> history = new RevisionHistory(fileStoreFolder).getHistory(
        new LocalJournalFile(journal),
        path);
while (history.hasNext()) {
    printWriter.println(history.next().toString(depth));
} 

I got the following output:

7b35a984-cf56-4a6d-a571-db38ac0f12aa:6={"root":{}}
c5b06947-64ea-48b9-a0c9-dbb65fdefb82:147={"root":{}}
8c0036ef-0160-4f6c-a408-a956f38b421d:7653={"root":{}}
55db2d1f-ffb0-4c47-ab7f-eca779bb4e08:450={"root":{}}
daadf7ca-0183-4a93-a94a-0c2347c89443:302={"root":{}}
fd234c75-9329-41f1-a9be-f7cef1d2ae7b:371={"root":{}}
3e86d6a1-76a5-4983-a779-48b3ee0e98fd:6={"root":{}}
5d05a2d8-f239-4fa0-a643-27bd281a6573:7102={"root":{}} 

that is fine - as far as I can tell.

Then, I run fileStore.fullGC(); - log attached full_gc.log.

Then, I run again the code that inspect the history, and I got the following output:

10cedc98-86ed-4a48-a22b-18fe8c34ed3e:7424={"root":{}}
7b35a984-cf56-4a6d-a571-db38ac0f12aa:6={"root":{}}
c5b06947-64ea-48b9-a0c9-dbb65fdefb82:147={"root":{}}
8c0036ef-0160-4f6c-a408-a956f38b421d:7653={"root":{}}

Segment 55db2d1f-ffb0-4c47-ab7f-eca779bb4e08 not found

The expected behaviour is that:

• either revision 55db2d1f-ffb0-4c47-ab7f-eca779bb4e08 is no more present in the history of the file store
• or revision is present and can be found

Despite this issue, it seems that everything is running smoothly, but I cannot tell whether this issue will bug some thing at some point.

Also note that, if I stop my application and run oak-run compact from the command line, the troubled revision is removed and I end up with just one revision:

Apache Jackrabbit Oak 1.42.0
07:53:00.534 [main] WARN  o.a.j.oak.segment.file.JournalReader - Skipping invalid journal entry: 
07:53:00.549 [main] WARN  o.a.j.oak.segment.file.JournalReader - Skipping invalid journal entry: 
635924e4-2e18-4bad-ac43-7347f4b1dfe0:7424={"root":{}}
 

(Please also note the two warnings printed by oak-run…).