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https://issues.apache.org/jira/browse/HDFS-16102?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
lei w updated HDFS-16102:
-------------------------
Description:
The current logic in removeBlocksAssociatedTo(...) is as follows：
{code:java}
void removeBlocksAssociatedTo(final DatanodeDescriptor node) {
providedStorageMap.removeDatanode(node);
for (DatanodeStorageInfo storage : node.getStorageInfos()) {
final Iterator<BlockInfo> it = storage.getBlockIterator();
//add the BlockInfos to a new collection as the
//returned iterator is not modifiable.
Collection<BlockInfo> toRemove = new ArrayList<>();
while (it.hasNext()) {
toRemove.add(it.next()); // First iteration : to put blocks to another
collection
}
for (BlockInfo b : toRemove) {
removeStoredBlock(b, node); // Another iteration : to remove blocks
}
}
// ......
}
{code}
In fact , we can use the first iteration to achieve this logic , so should we
remove the redundant iteration to save time and memory?
was:
The current logic in removeBlocksAssociatedTo(...) is as follows：
{code:java}
void removeBlocksAssociatedTo(final DatanodeDescriptor node) {
providedStorageMap.removeDatanode(node);
for (DatanodeStorageInfo storage : node.getStorageInfos()) {
final Iterator<BlockInfo> it = storage.getBlockIterator();
//add the BlockInfos to a new collection as the
//returned iterator is not modifiable.
Collection<BlockInfo> toRemove = new ArrayList<>();
while (it.hasNext()) {
toRemove.add(it.next()); // First iteration : to put blocks to another
collection
}
for (BlockInfo b : toRemove) {
removeStoredBlock(b, node); // Another iteration : to remove blocks
}
}
// ......
}
{code}
In fact , we can use the first iteration to achieve this logic , so should we
remove the redundant iteration to save time?
> Remove redundant iteration in BlockManager#removeBlocksAssociatedTo(...) to
> save time
> --------------------------------------------------------------------------------------
>
> Key: HDFS-16102
> URL: https://issues.apache.org/jira/browse/HDFS-16102
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: namenode
> Reporter: lei w
> Assignee: lei w
> Priority: Minor
> Attachments: HDFS-16102.001.patch
>
>
> The current logic in removeBlocksAssociatedTo(...) is as follows：
> {code:java}
> void removeBlocksAssociatedTo(final DatanodeDescriptor node) {
> providedStorageMap.removeDatanode(node);
> for (DatanodeStorageInfo storage : node.getStorageInfos()) {
> final Iterator<BlockInfo> it = storage.getBlockIterator();
> //add the BlockInfos to a new collection as the
> //returned iterator is not modifiable.
> Collection<BlockInfo> toRemove = new ArrayList<>();
> while (it.hasNext()) {
> toRemove.add(it.next()); // First iteration : to put blocks to
> another collection
> }
> for (BlockInfo b : toRemove) {
> removeStoredBlock(b, node); // Another iteration : to remove blocks
> }
> }
> // ......
> }
> {code}
> In fact , we can use the first iteration to achieve this logic , so should
> we remove the redundant iteration to save time and memory?
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