[ https://issues.apache.org/jira/browse/HBASE-2023?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12788157#action_12788157 ]
Joydeep Sen Sarma commented on HBASE-2023: ------------------------------------------ i am looking at some pauses while loading data in and trying to figure out if this is applicable. we have multiple machines loading data - each multithreaded - each thread writing to a different range. all get paused at the same times once in a while. there's no cpu/io going on the region servers when this happens. (next time i reproduce - i will get a jstack dump on the regionservers). can this happen on region splits? (I sure wasn't going any table offline/online during the test). > Client sync block can cause 1 thread of a multi-threaded client to block all > others > ----------------------------------------------------------------------------------- > > Key: HBASE-2023 > URL: https://issues.apache.org/jira/browse/HBASE-2023 > Project: Hadoop HBase > Issue Type: Bug > Affects Versions: 0.20.2 > Reporter: ryan rawson > > Take a highly multithreaded client, processing a few thousand requests a > second. If a table goes offline, one thread will get stuck in > "locateRegionInMeta" which is located inside the following sync block: > synchronized(userRegionLock){ > return locateRegionInMeta(META_TABLE_NAME, tableName, row, > useCache); > } > So when other threads need to find a region (EVEN IF ITS CACHED!!!) it will > encounter this sync and wait. > This can become an issue on a busy thrift server (where I first noticed the > problem), one region offline can prevent access to all other regions! > Potential solution: narrow this lock, or perhaps just get rid of it > completely. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.