[
https://issues.apache.org/jira/browse/HBASE-20471?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16533226#comment-16533226
]
Biju Nair commented on HBASE-20471:
-----------------------------------
Would like to get clarifications for some of the comments
{quote}unless the user changes the Durability setting, and then it's unclear,
but we don't expect this for the normal case
{quote}
Does this mean that if {{FSYNC_WAL}} is set at the cluster level (site.xml) and
user sets {{SYNC_WAL}} as the durability for the mutation in code, it is not
clear which durability takes in effect or it will be {{SYNC_WAL}} for that
mutation. Assuming the latter.
{quote}If the user assumes SYNC_WAL or FSYNC_WAL is applied to every mutation,
this is not correct and should be documented.
{quote}
Assuming that the set durability will be applicable to all the mutations in a
batch as with discussion on {{SKIP_WAL}}?
> Recheck the design and implementation of FSYNC_WAL durability for WAL
> ---------------------------------------------------------------------
>
> Key: HBASE-20471
> URL: https://issues.apache.org/jira/browse/HBASE-20471
> Project: HBase
> Issue Type: Task
> Reporter: Yu Li
> Priority: Major
>
> This is something derived from discussion in HBASE-19024 around [this
> comment|https://issues.apache.org/jira/browse/HBASE-19024?focusedCommentId=16445592&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-16445592]
> We have been supplying user the API to set durability per mutation for a long
> time, by design the SYNC_WAL durability to call {{FSDataOutputStream#hflush}}
> and FSYNC_WAL {{FSDataOutputStream#hsync}}, while in implementation we have
> been calling hflush for FSYNC_WAL also until HBASE-19024. Although
> HBASE-19024 tried to fix the syntax with good willing, the implementation
> there cannot assure the FSYNC_WAL edits are truly hsync'ed due to the
> disruptor mechanism used in WAL implementation. Here in this JIRA we aim to
> have more discussion and give it a complete solution.
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
