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https://issues.apache.org/jira/browse/HDDS-1499?focusedWorklogId=242133&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-242133
]
ASF GitHub Bot logged work on HDDS-1499:
----------------------------------------
Author: ASF GitHub Bot
Created on: 14/May/19 23:25
Start Date: 14/May/19 23:25
Worklog Time Spent: 10m
Work Description: arp7 commented on pull request #798: HDDS-1499.
OzoneManager Cache.
URL: https://github.com/apache/hadoop/pull/798#discussion_r284037057
##########
File path:
hadoop-hdds/common/src/main/java/org/apache/hadoop/utils/db/TypedTable.java
##########
@@ -69,8 +94,40 @@ public boolean isEmpty() throws IOException {
return rawTable.isEmpty();
}
+ /**
+ * Returns the value mapped to the given key in byte array or returns null
+ * if the key is not found.
+ *
+ * First it will check from cache, if it has entry return the value
+ * otherwise, get from the RocksDB table.
+ *
+ * @param key metadata key
+ * @return VALUE
+ * @throws IOException
+ */
@Override
public VALUE get(KEY key) throws IOException {
+ // Here the metadata lock will guarantee that cache is not updated for same
+ // key during get key.
+ if (cache != null) {
+ CacheValue<VALUE> cacheValue = cache.get(new CacheKey<>(key));
+ if (cacheValue == null) {
+ return getFromTable(key);
+ } else {
+ // Doing this because, if the Cache Value Last operation is deleted
+ // means it will eventually removed from DB. So, we should return null.
+ if (cacheValue.getLastOperation() != CacheValue.OperationType.DELETED)
{
+ return cacheValue.getValue();
+ } else {
+ return null;
Review comment:
Instead of making delete operation a special case, in case of delete we can
just push a null value into the cache. So it will automatically return null.
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Issue Time Tracking
-------------------
Worklog Id: (was: 242133)
Time Spent: 4.5h (was: 4h 20m)
> OzoneManager Cache
> ------------------
>
> Key: HDDS-1499
> URL: https://issues.apache.org/jira/browse/HDDS-1499
> Project: Hadoop Distributed Data Store
> Issue Type: Sub-task
> Components: Ozone Manager
> Reporter: Bharat Viswanadham
> Assignee: Bharat Viswanadham
> Priority: Major
> Labels: pull-request-available
> Time Spent: 4.5h
> Remaining Estimate: 0h
>
> In this Jira, we shall implement a cache for Table.
> As with OM HA, we are planning to implement double buffer implementation to
> flush transaction in a batch, instead of using rocksdb put() for every
> operation. When this comes in to place we need cache in OzoneManager HA to
> handle/server the requests for validation/returning responses.
>
> This Jira will implement Cache as an integral part of the table. In this way
> users using this table does not need to handle like check cache/db. For this,
> we can update get API in the table to handle the cache.
>
> This Jira will implement:
> # Cache as a part of each Table.
> # Uses this cache in get().
> # Exposes api for cleanup, add entries to cache.
> Usage to add the entries in to cache will be done in further jira's.
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