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Posted to issues@ignite.apache.org by "Kirill Gusakov (Jira)" <ji...@apache.org> on 2022/12/28 00:48:00 UTC
[jira] [Updated] (IGNITE-18474) Read sql queries has significant number of RAFT write commands
[ https://issues.apache.org/jira/browse/IGNITE-18474?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Kirill Gusakov updated IGNITE-18474:
------------------------------------
Description:
It is counterintuitive, but at the moment usual {{select * from table where pk = 1}} query produces even more raft WriteCommands, than insert query.
The reason is: we have numberOfPartitions*TxCleanupCommand + FinishTxCommand for each select query. With the default number of partitons 25 and 1-node installation we will have 26 synced writes to rocksDB per query. Together with https://issues.apache.org/jira/browse/IGNITE-18475 it blows up our latency in 10times per simple select by primary key query.
Possible solution:
- Detect, that we have only select query in transaction and use read-only path for these type of queries
> Read sql queries has significant number of RAFT write commands
> --------------------------------------------------------------
>
> Key: IGNITE-18474
> URL: https://issues.apache.org/jira/browse/IGNITE-18474
> Project: Ignite
> Issue Type: Task
> Reporter: Kirill Gusakov
> Priority: Major
>
> It is counterintuitive, but at the moment usual {{select * from table where pk = 1}} query produces even more raft WriteCommands, than insert query.
> The reason is: we have numberOfPartitions*TxCleanupCommand + FinishTxCommand for each select query. With the default number of partitons 25 and 1-node installation we will have 26 synced writes to rocksDB per query. Together with https://issues.apache.org/jira/browse/IGNITE-18475 it blows up our latency in 10times per simple select by primary key query.
>
> Possible solution:
> - Detect, that we have only select query in transaction and use read-only path for these type of queries
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