[
https://issues.apache.org/jira/browse/MAPREDUCE-7241?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Zhihua Deng updated MAPREDUCE-7241:
-----------------------------------
Description:
This case sometimes sees in hive when user issues queries over all partitions
by mistakes. The file status cached when listing status could accumulate to
over 3g. After digging into the dumped memory, the LocatedBlock occupies
about 50%(sometimes over 60%) memory that retained by LocatedFileStatus, as
shows followed,
!filestatus.png!
Right now we only extract the block locations info from LocatedFileStatus, the
datanode infos(types) or block token are not taken into account. So there is no
need to cache LocatedBlock, as do like this:
BlockLocation[] blockLocations = dedup(stat.getBlockLocations());
LocatedFileStatus shrink = new LocatedFileStatus(stat, blockLocations);
private static BlockLocation[] dedup(BlockLocation[] blockLocations) {
BlockLocation[] copyLocs = new BlockLocation[blockLocations.length];
int i = 0;
for (BlockLocation location : blockLocations)
{ copyLocs[i++] = new BlockLocation(location); }
return copyLocs;
}
was:
This case sometimes sees in hive when user issues queries over all partitions
by mistakes. The file status cached when listing status could accumulate to
over 3g. After digging into the dumped memory, the LocatedBlock occupies
about 50%(sometimes over 60%) memory that retained by LocatedFileStatus, as
shows in the filestatus.png attached.
Now we only extract the block locations info from LocatedFileStatus, the
datanode infos(types) or block token are not taken into account. So there is no
need to cache LocatedBlock, as do like this:
```java
BlockLocation[] blockLocations = dedup(stat.getBlockLocations());
LocatedFileStatus shrink = new LocatedFileStatus(stat, blockLocations);
private static BlockLocation[] dedup(BlockLocation[] blockLocations) {
BlockLocation[] copyLocs = new BlockLocation[blockLocations.length];
int i = 0;
for (BlockLocation location : blockLocations) {
copyLocs[i++] = new BlockLocation(location);
}
return copyLocs;
}
```
> FileInputFormat listStatus causes oom when there are lots of files
> ------------------------------------------------------------------
>
> Key: MAPREDUCE-7241
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-7241
> Project: Hadoop Map/Reduce
> Issue Type: Improvement
> Components: job submission
> Affects Versions: 2.6.1
> Reporter: Zhihua Deng
> Priority: Major
> Attachments: filestatus.png
>
>
> This case sometimes sees in hive when user issues queries over all partitions
> by mistakes. The file status cached when listing status could accumulate to
> over 3g. After digging into the dumped memory, the LocatedBlock occupies
> about 50%(sometimes over 60%) memory that retained by LocatedFileStatus, as
> shows followed,
> !filestatus.png!
> Right now we only extract the block locations info from LocatedFileStatus,
> the datanode infos(types) or block token are not taken into account. So there
> is no need to cache LocatedBlock, as do like this:
> BlockLocation[] blockLocations = dedup(stat.getBlockLocations());
> LocatedFileStatus shrink = new LocatedFileStatus(stat, blockLocations);
> private static BlockLocation[] dedup(BlockLocation[] blockLocations) {
> BlockLocation[] copyLocs = new BlockLocation[blockLocations.length];
> int i = 0;
> for (BlockLocation location : blockLocations)
> { copyLocs[i++] = new BlockLocation(location); }
> return copyLocs;
> }
>
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