Hi, I'm currently having some scan speed issues with Accumulo and I would like to understand why and how can I solve it. I have geographical data and I use as primary key the day and then the geohex, which is a linearisation of lat and lon. The reason for this key is that I always query the data for one day but for a set of geohexes with represent a zone, so with this schema I can scan use a single scan to read all the data for one day with few seeks. My problem is that the scan is painfully slow: for instance, to read 5617019 rows it takes around 17 seconds and the scan speed is 13MB/s, less than 750k scan entries/s and around 300 seeks. I enable the tracer and this is what I've got
17325+0 Dice@srv1 Dice.query 11+1 Dice@srv1 scan 11+1 Dice@srv1 scan:location 5+13 Dice@srv1 scan 5+13 Dice@srv1 scan:location 4+19 Dice@srv1 scan 4+19 Dice@srv1 scan:location 5+23 Dice@srv1 scan 4+24 Dice@srv1 scan:location I'm not sure how to speedup the scanning. I have the following question: - is this speed normal? - can I involve more servers in the scan? Right now only two server have the ranges but with a cluster of 15 machines it would be nice to involve more of them. Is it possible? Thanks, Mario -- Mario Pastorelli | TERALYTICS *software engineer* Teralytics AG | Zollstrasse 62 | 8005 Zurich | Switzerland phone: +41794381682 email: [email protected] www.teralytics.net Company registration number: CH-020.3.037.709-7 | Trade register Canton Zurich Board of directors: Georg Polzer, Luciano Franceschina, Mark Schmitz, Yann de Vries This e-mail message contains confidential information which is for the sole attention and use of the intended recipient. Please notify us at once if you think that it may not be intended for you and delete it immediately.
