[
https://issues.apache.org/jira/browse/HDDS-1986?focusedWorklogId=324797&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-324797
]
ASF GitHub Bot logged work on HDDS-1986:
----------------------------------------
Author: ASF GitHub Bot
Created on: 08/Oct/19 01:30
Start Date: 08/Oct/19 01:30
Worklog Time Spent: 10m
Work Description: arp7 commented on pull request #1588: HDDS-1986. Fix
listkeys API.
URL: https://github.com/apache/hadoop/pull/1588#discussion_r332303770
##########
File path:
hadoop-ozone/ozone-manager/src/main/java/org/apache/hadoop/ozone/om/OmMetadataManagerImpl.java
##########
@@ -680,26 +688,85 @@ public boolean isBucketEmpty(String volume, String
bucket)
seekPrefix = getBucketKey(volumeName, bucketName + OM_KEY_PREFIX);
}
int currentCount = 0;
- try (TableIterator<String, ? extends KeyValue<String, OmKeyInfo>> keyIter =
- getKeyTable()
- .iterator()) {
- KeyValue<String, OmKeyInfo> kv = keyIter.seek(seekKey);
- while (currentCount < maxKeys && keyIter.hasNext()) {
- kv = keyIter.next();
- // Skip the Start key if needed.
- if (kv != null && skipStartKey && kv.getKey().equals(seekKey)) {
- continue;
+
+
+ TreeMap<String, OmKeyInfo> cacheKeyMap = new TreeMap<>();
+ Set<String> deletedKeySet = new TreeSet<>();
+ Iterator<Map.Entry<CacheKey<String>, CacheValue<OmKeyInfo>>> iterator =
+ keyTable.cacheIterator();
+
+ //TODO: We can avoid this iteration if table cache has stored entries in
+ // treemap. Currently HashMap is used in Cache. HashMap get operation is an
+ // constant time operation, where as for treeMap get is log(n).
+ // So if we move to treemap, the get operation will be affected. As get
+ // is frequent operation on table. So, for now in list we iterate cache map
+ // and construct treeMap which match with keyPrefix and are greater than or
+ // equal to startKey. Later we can revisit this, if list operation
+ // is becoming slow.
+ while (iterator.hasNext()) {
+ Map.Entry< CacheKey<String>, CacheValue<OmKeyInfo>> entry =
+ iterator.next();
+
+ String key = entry.getKey().getCacheKey();
+ OmKeyInfo omKeyInfo = entry.getValue().getCacheValue();
+ // Making sure that entry in cache is not for delete key request.
+
+ if (omKeyInfo != null) {
+ if (key.startsWith(seekPrefix) && key.compareTo(seekKey) >= 0) {
+ cacheKeyMap.put(key, omKeyInfo);
}
+ } else {
+ deletedKeySet.add(key);
+ }
+ }
+
+ // Get maxKeys from DB if it has.
+
+ try (TableIterator<String, ? extends KeyValue<String, OmKeyInfo>>
+ keyIter = getKeyTable().iterator()) {
+ KeyValue< String, OmKeyInfo > kv;
+ keyIter.seek(seekKey);
+ // we need to iterate maxKeys + 1 here because if skipStartKey is true,
+ // we should skip that entry and return the result.
+ while (currentCount < maxKeys + 1 && keyIter.hasNext()) {
+ kv = keyIter.next();
if (kv != null && kv.getKey().startsWith(seekPrefix)) {
- result.add(kv.getValue());
- currentCount++;
+
+ // Entry should not be marked for delete, consider only those
+ // entries.
+ if(!deletedKeySet.contains(kv.getKey())) {
+ cacheKeyMap.put(kv.getKey(), kv.getValue());
+ currentCount++;
+ }
} else {
// The SeekPrefix does not match any more, we can break out of the
// loop.
break;
}
}
}
+
+ // Finally DB entries and cache entries are merged, then return the count
+ // of maxKeys from the sorted map.
+ currentCount = 0;
+
+ for (Map.Entry<String, OmKeyInfo> cacheKey : cacheKeyMap.entrySet()) {
Review comment:
The second iteration is unfortunate. We should see if there is a way to
avoid it.
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Issue Time Tracking
-------------------
Worklog Id: (was: 324797)
Time Spent: 1h 10m (was: 1h)
> Fix listkeys API
> ----------------
>
> Key: HDDS-1986
> URL: https://issues.apache.org/jira/browse/HDDS-1986
> Project: Hadoop Distributed Data Store
> Issue Type: Sub-task
> Reporter: Bharat Viswanadham
> Assignee: Bharat Viswanadham
> Priority: Major
> Labels: pull-request-available
> Time Spent: 1h 10m
> Remaining Estimate: 0h
>
> This Jira is to fix listKeys API in HA code path.
> In HA, we have an in-memory cache, where we put the result to in-memory cache
> and return the response, later it will be picked by double buffer thread and
> it will flush to disk. So, now when do listkeys, it should use both in-memory
> cache and rocksdb key table to list keys in a bucket.
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