[GitHub] incubator-hawq pull request: modify metadata cache read lock logic

[wengyanqing]

Github user wengyanqing commented on a diff in the pull request:

    https://github.com/apache/incubator-hawq/pull/146#discussion_r46654739
  
    --- Diff: src/backend/cdb/cdbmetadatacache.c ---
    @@ -619,6 +619,9 @@ BlockLocation *GetHdfsFileBlockLocations(const 
HdfsFileInfo *file_info, uint64_t
                 if (cache_entry->block_num <= 1)
                 {
                     // only one file, re-fetch 
    +                LWLockRelease(MetadataCacheLock); 
    +                
    +                LWLockAcquire(MetadataCacheLock, LW_EXCLUSIVE);
    --- End diff --
    
    Hi George,
    
    Thanks for your comment. It only has one lock (MetadataCacheLock) and one 
resource (MetadataCache) which lock on, so it should not cause dead lock.



---
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 infrastruct...@apache.org or file a JIRA ticket
with INFRA.
---