carbondata-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From manishgupta88 <...@git.apache.org>
Subject [GitHub] incubator-carbondata pull request #337: [CARBONDATA-428] Removed Redundant C...
Date Mon, 21 Nov 2016 13:01:55 GMT
Github user manishgupta88 commented on a diff in the pull request:

    https://github.com/apache/incubator-carbondata/pull/337#discussion_r88889114
  
    --- Diff: core/src/main/java/org/apache/carbondata/core/cache/CacheProvider.java ---
    @@ -84,14 +84,13 @@ public static CacheProvider getInstance() {
         //check if cache is null for given cache type, if null create one
         if (!dictionaryCacheAlreadyExists(cacheType)) {
           synchronized (lock) {
    -        if (!dictionaryCacheAlreadyExists(cacheType)) {
    -          if (null == cacheTypeToLRUCacheMap.get(cacheType)) {
    -            createLRULevelCacheInstance(cacheType);
    -          }
    -          createDictionaryCacheForGivenType(cacheType, carbonStorePath);
    +        if (null == cacheTypeToLRUCacheMap.get(cacheType)) {
    +          createLRULevelCacheInstance(cacheType);
             }
    +        createDictionaryCacheForGivenType(cacheType, carbonStorePath);
    --- End diff --
    
    @PallaviSingh1992 ....dictionaryCacheAlreadyExists will check if for a given cache type
(Forward/Reverse), the object has already been created. Now this check is before and inside
synchronized block to handle concurrent access (double locking mechanism). If this check is
removed inside the synchronized block then it can happen that in concurrent scenarios, multiple
threads end up in creating multiple objects for the same cache type and the object in the
map keeps getting overridden. 
    Therefore I think that this double check is required. Please correct me if I am wrong.


---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at infrastructure@apache.org or file a JIRA ticket
with INFRA.
---

Mime
View raw message