Hi , Can you please provide more details : what do you mean elease server-side resources?
I get the similar Issue and the only what I do is return HTable to the pool. I do nothing to release server-side resources. Actually I don't know how to do it from java client? Thanks Oleg. On Thu, Jul 15, 2010 at 7:14 AM, Ryan Rawson <[email protected]> wrote: > One thing to watch out for is closing scanners when you are done with > them to release server-side resources. Without doing that it would be > possible to overwhelm the server. We currently don't protect against > this, but its quite possible we should. > > On Wed, Jul 14, 2010 at 9:07 PM, Jonathan Gray <[email protected]> wrote: > > Hard to imagine a scan of 1500 rows (~100k total KVs) taking down > anything, but it is of course possible. > > > > Did the RSs actually die or the increments just got slow enough to > timeout your application? If they got slow, how slow did they get and how > fast do they usually go? > > > > If you put up logs from the RSs during this time we might be able to see > if there's anything strange going on. > > > > On this scanner, did you have the block cache enabled or disabled? I'd > recommend disabling the block cache on the Scan object, just in case it was > increased GC activity that hurt performance. On big scans I've seen this > make a difference. > > > > JG > > > >> -----Original Message----- > >> From: Vaibhav Puranik [mailto:[email protected]] > >> Sent: Wednesday, July 14, 2010 8:57 PM > >> To: [email protected] > >> Subject: Scanner call crashed regionserver under load > >> > >> Hi all, > >> > >> > >> We experienced a downtime in our HBase installation today. > >> > >> We have our HBase hosted in EC2 with 1 master (with ZK) and 3 slaves > >> (all of > >> them are m1.large). We are using HBase version 0.20.4 > >> > >> We have a method that opens a scanner and retrieves some values. The > >> method > >> approximately scans 300 rows. Each row has three column families and > >> approximately 75 longs. > >> The table is fairly small and in total the table has approximately 1500 > >> rows. > >> > >> We tried calling this method under huge traffic and the CPU of the > >> regionserver that hosted this table spiked to 100%. It brought down our > >> application. > >> > >> We are doing multiple incrementColumnValue calls for every request for > >> this > >> traffic and HBase seems to take it well. > >> > >> So, does that mean, it's a bad idea to call a scanner under huge > >> traffic? > >> Will this problem get solved if we make a new table and store the > >> values > >> with a different key so that the exact value can be retrieved (with a > >> Get > >> call) ? Are there any other ways to resolve this hotspotting without > >> duplicating data? > >> > >> Are we limited by what a machine can handle if we have a fairly small > >> table > >> (that can fit in a region server or possibly in a single region)? Are > >> there > >> any creative solutions people are using? > >> > >> Regards, > >> Vaibhav Puranik > >> GumGum > > >
