[
https://issues.apache.org/jira/browse/IGNITE-23417?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17889212#comment-17889212
]
Ivan Zlenko commented on IGNITE-23417:
--------------------------------------
LGTM
> Fix race between compaction and KeyValueStorage#range
> -----------------------------------------------------
>
> Key: IGNITE-23417
> URL: https://issues.apache.org/jira/browse/IGNITE-23417
> Project: Ignite
> Issue Type: Bug
> Reporter: Kirill Tkalenko
> Assignee: Kirill Tkalenko
> Priority: Major
> Labels: ignite-3
> Fix For: 3.0
>
> Time Spent: 10m
> Remaining Estimate: 0h
>
> I found that in IGNITE-23288 a some problem with
> *org.apache.ignite.internal.metastorage.server.KeyValueStorage#range* was not
> solved.
> To understand it, let's look at an example:
> * Let's say there is a key "bar" and it has revisions 1, 3, 5 (tombstone).
> * We set the compaction revision to 5, via
> *KeyValueStorage#setCompactionRevision*.
> * We waited for complete all cursors on revision less than or equal to 5.
> * We invoke *KeyValueStorage#compact* on revision 5 and let's say it will be
> quite long.
> * We will not be able to create a cursor on revision 5, but on 6 it is quite
> possible.
> * We create a cursor for revision 6.
> * Cursor reaches the key "bar" and what can happen:
> # Compaction deleted the key "bar" from storage before opening the cursor -
> then everything is {color:#00875A}fine{color}.
> # Compaction did not have time to delete the "bar" key - the cursor will
> return an entry with revision 5, which {color:#DE350B}should not
> present{color}.
> # Compaction started deleting the "bar" key in parallel - the cursor will
> either {color:#DE350B}get a value for revision 5 or throw an error{color}.
> In this ticket we need to fix cases 2 and 3.
> Also, we must not forget the case that if the cursor was created on a
> revision less than or equal to the new revision of the compaction, from the
> example this is on revision 5 but strictly before calling
> *KeyValueStorage#setCompactionRevision(5)*. Then we must return the entry on
> revision 5 after *KeyValueStorage#setCompactionRevision(5)*.
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
