[
https://issues.apache.org/jira/browse/CASSANDRA-14570?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16547248#comment-16547248
]
Shichao An commented on CASSANDRA-14570:
----------------------------------------
There are some mistakes in my initial description of the issue. I just updated
it. The correction is: when total size of commit logs reaches
commitlog_total_space_in_mb, only the writes to cdc=true tables will fail,
rather than all writes will fail. (mutation.trackedByCDC()).
[~JoshuaMcKenzie] "cl size > free_space on volume". I think you mean total
space of the volume, right? i.e. "whether size + cl size > total space of the
volume". We can definitely handle it, but it seems it's more of the problem of
handling commitlog_total_space_in_mb, as the user can set it to an arbitrary
value, which can be greater than total disk space.
For you second point, I definitely agree. The cdc_total_space_in_mb is kind of
misleading. "extra buffer space" name makes more sense.
> Improper default value of cdc_total_space_in_mb
> -----------------------------------------------
>
> Key: CASSANDRA-14570
> URL: https://issues.apache.org/jira/browse/CASSANDRA-14570
> Project: Cassandra
> Issue Type: Bug
> Components: Configuration
> Reporter: Shichao An
> Assignee: Shichao An
> Priority: Minor
> Labels: CDC
>
> The code for calculating cdc_total_space_in_mb in DatabaseDescriptor.java
> does not reflect the latest architecture introduced by CASSANDRA-12148.
> In short, cdc_total_space_in_mb should be equal or greater than
> commitlog_total_space_in_mb; otherwise, the writes will fail when on-disk
> commit logs size reaches the value of cdc_total_space_in_mb. For example, If
> cdc_total_space_in_mb is 4096 and commitlog_total_space_in_mb is 8192, when
> we enabled the cdc_enabled flag (even if we didn't enable cdc=true on any
> table), when total size of commit logs reaches 4096 MB, there is the same of
> amount of hard links in cdc_raw directory, that is, 4096 MB of cdc logs.
> Then, if a table has cdc=true, the writes will fail in that table because the
> CommitLogSegmentManagerCDC will be unable to process new CDC segments. (See
> allocate and processNewSegment in CommitLogSegmentManagerCDC class)
>
> I will attach patches later.
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
