You are viewing a plain text version of this content. The canonical link for it is here.
Posted to issues@spark.apache.org by "Eric Liang (JIRA)" <ji...@apache.org> on 2016/10/18 20:01:03 UTC
[jira] [Updated] (SPARK-17994) Add back a file status cache for
catalog tables
[ https://issues.apache.org/jira/browse/SPARK-17994?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Eric Liang updated SPARK-17994:
-------------------------------
Issue Type: Sub-task (was: Improvement)
Parent: SPARK-17861
> Add back a file status cache for catalog tables
> -----------------------------------------------
>
> Key: SPARK-17994
> URL: https://issues.apache.org/jira/browse/SPARK-17994
> Project: Spark
> Issue Type: Sub-task
> Reporter: Eric Liang
>
> In SPARK-16980, we removed the full in-memory cache of table partitions in favor of loading only needed partitions from the metastore. This greatly improves the initial latency of queries that only read a small fraction of table partitions.
> However, since the metastore does not store file statistics, we need to discover those from remote storage. With the loss of the in-memory file status cache this has to happen on each query, increasing the latency of repeated queries over the same partitions.
> The proposal is to add back a per-table cache of partition contents, i.e. Map[Path, Array[FileStatus]]. This cache would be retained per-table, and would be invalidated through refreshTable() and refreshByPath(). Unlike the prior cache, it can be incrementally updated as new partitions are read.
> cc [~michael]
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
---------------------------------------------------------------------
To unsubscribe, e-mail: issues-unsubscribe@spark.apache.org
For additional commands, e-mail: issues-help@spark.apache.org