Please be patient when waiting for a response. Apache HBase is made up
of community volunteers. Your expectation should be on the order of many
hours (although, we strive to be faster).
I'd recommend that you begin by looking at a newer release than 0.94.2
as there have likely been over 50 (guessing) newer releases since this
release was made.
In general, rowlocks must be acquired to ensure that multiple updates to
the same row are applied in full. Consider two transactions against the
same row:
tx1: row=r1 set a=1, b=1
tx2: row=r1 set a=2, b=2
After tx1 and tx2 are both applied, r1 must either have the columns
a=1,b=1 or a=2,b=2. It must not have a=1,b=2 or a=2,b=1. This is why
some form of mutual exclusion must be applied inside of the RegionServer.
On 8/28/17 10:06 AM, JH Lin wrote:
ping...
在2017年08月28 17时55分, "JH Lin"<[email protected]>写道:
hi all,i dived into hbase source these days.when i read at the
HRegion#doMiniBatchMutation(...) block then one question flashed in my mind:why
did writer use at least one rowlock to implement mutation?(ie.Puts or Deletes
etc)
since if i have 10 rows to update,then it means that 9 rows have no
rowlocks.so is 'at least one rowlock' more symbolic than practical significane?
AFAIK now,i think it's used to verify hbase' basic functions eg. rowlock
mechanism.
---
release:hbase-0.94.2
pardon me if it's a bit old,but i just wonder to know its principle inside it.
one more thing, my english is poor,so sorry for any typo.
many thanks~
