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https://issues.apache.org/jira/browse/USERGRID-909?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Jeffrey updated USERGRID-909:
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Sprint: Usergrid 28 (was: Usergrid 27)
> Evaluate removing cache from edge shard management
> --------------------------------------------------
>
> Key: USERGRID-909
> URL: https://issues.apache.org/jira/browse/USERGRID-909
> Project: Usergrid
> Issue Type: Story
> Components: Stack
> Reporter: Todd Nine
> Assignee: Todd Nine
>
> Currently, using caches with the proposal phase for new shards has caused
> large numbers of tombstones. Review the algorithm, and determine the cause
> of the additional shard proposals.
> Usergrid currently performs 5 shard lookups on write and most miss the cache.
> We'll change the following
> *Shard allocation*
> Shard allocation will not perform a propose + check phase. The following
> algorithm will occur. This must occur at EACH_QUORUM to ensure that we have
> consensus across regions.
> Any node will propose a new shard pivot. This pivot will have compacted set
> to false, and will have a column timestamp of a new timeuuid in micros
> The proposing node will then read back all compacted = false shard pivots.
> The shard pivot with the minimum timestamp will be retained, all others will
> be deleted as proposals. This will function similarly to distributed read
> locks in Cassandra. Lowest proposed value always wins.
> Allocation is complete
> *Shard compaction*
> After a successful proposal allocation, the allocating node will copy all
> edges from the previously compacted shard into the new shard. It will
> continue to copy until no new edges are returned on read.
> Once read has been completed, all edges that were copied can be deleted from
> the previous shard.
> This target shard will be marked as compacted
> *Consistency*
> When performing consistency, we will need a higher consistency level. To
> ensure that shards exist worldwide, proposal + selection should occur at
> EACH_QUORUM. Standard reads can occur as LOCAL_QUORUM
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