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How to improve random read latency?
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| May 29, 2011 | |||||
 Harold Lim |
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Introduce Random latency April 6, 2011 12:21:08 PM I want to run some tests where I incorporate random latency in some of the nodes (that varies over time). I think the best place is to place a 'sleep (random(10 to 50 seconds)) function' somewhere in the source code of cassandra. Or maybe the sleep… Re: Read Latency October 19, 2010 08:22:25 AM The changes seems to do the trick. We are down to about 1/2 of the original quorum read performance. I did not see any more errors. More than 3 seconds on the client side is still not acceptable to us. We need the data in Python, but would we be… Read Latency October 14, 2010 03:18:51 PM Can someone help to determine the anatomy of a quorum read? We are trying to understand why CFSTATS reports one time and the client actual gets data back almost 4x slower. Below are the debug logs from a read that all 3 nodes reported < 2.5secs… Read Latency October 6, 2010 08:56:05 AM I have been seeing some strange trends in read latency that I wanted to throw out there to find some explanations. We are running .6.5 in a 10 node cluster rf=3. We find that the read latency reported by the cfstats is always about 1/4 of the… High read latency June 4, 2010 01:26:22 AM we have a SupperCF which may have up to 1000 supper columns and 50000 clumns for each supper column, the read latency may go up to 50ms (even higher), I think it's a long time to response, how to tune the storage config to optimize the performace?… How to reduce the Read Latency. May 20, 2011 02:43:36 AM Hi All, I'm running three cassandra 0.7.4 nodes in a cluster, and I give 2G memory to each node. Now, I get the cfstats here: Keyspace: UserMap Read Count: 38411 Read Latency: 123.54214613001484 ms. Write Count: 44155 Write Latency:… Tracking down read latency February 2, 2011 11:36:04 PM Hello. We?re encountering some high read latency issues. But our main Cass expert is out-of-office so it falls to me. We're more read than write, though there doesn't seem to be many pending reads. I have seen active/pending row-read at three or… HBase read latency March 26, 2011 12:01:37 PM Hi guys, On what factors does HBase read latency primarily depend? What would be the approx theoretical limit for read latency in v0.90.1 on a cluster of 7 nodes (16 core/16 GB RAM on 5 machines and 36 GB on the other two)? I have an application… Read Latency Degradation December 16, 2010 04:36:06 PM We are running .6.8 and are reaching 1tb/node in a 10 node cluster rf=3. Our reads times seem to be getting worse as we load data into the cluster, and I am worried there is a scale problem in terms of large column families. All benchmarks/times… read latency in cassandra February 4, 2011 01:14:51 PM Hi all, It often takes more than two seconds to load: - one row of ~450 events comprising ~600k - cluster size of 1 - client is pycassa 1.04 - timeout on recv - cold read (I believe) - load generally < 0.5 on a 4-core machine, 2 EC2 instance… CF Read and Write Latency Histograms February 4, 2011 11:42:53 AM Hi All, I suspect that Write and Read Latency column headers need to be swapped. I am running a bulk load with no reads on this CF but I see Read column with values while the Write column has zeros only. The MBean shows the values correctly. … Cassandra performance and read/write latency July 6, 2010 10:26:46 AM Greetings Cassandra Developers! We've been trying to benchmark Cassandra performance and have developed a test client written in C++ that uses multiple threads to send out a large number of write and read requests (as fast as the server can… HBase tuning - minimise table read latency January 10, 2011 04:00:49 AM Hi All, I have an application with two HBase tables. One table is written to frequently, by a crawler writing web pages. Another table is written to occasionally (the result of some processing), but end users read data from this table, and I… Read latency on one ColumnFamily greater than the rest of Column Families .. June 11, 2010 02:32:26 PM So I have setup some test with Cassandra (with OCM). Though not very impressed with the single read speeds , I have observed that it does scale very well even with numerous number of concurrent readers .. However I have observed that no matter what… improve read performance for read-only store February 10, 2011 07:19:37 PM Hi, I have deployed 2 application in production using Voldemort and am concentrating on performance and monitoring now. I have been going through the discussions on this group looking for fine-tuning server/ client configuration or any other tips… Re: improve read performance for read-only store February 21, 2011 12:24:43 AM Hi Anani, >>> I have deployed 2 application in production using Voldemort and am >>> concentrating on performance and monitoring now. I have been going >>> through the discussions on this group looking for fine-tuning… improving random read performance August 19, 2010 07:53:57 PM I am currently running under Hbasev0.20.3. I increased the block cache to .4 from .2. The heap size is 2GB. The default regionserver handler count is 25 in hbase-default.xml. Will try LZO compression. What are other performance tunings I can do ?… The hfile.block.cache.size = 0 performance is better than default(0.2) in random read? Is it possibl October 20, 2010 10:19:49 PM Hi all, I run my performance testing in random read, but I got the hfile.block.cache.size = 0 performance is better than default, Is it possible? My cluster (4 nodes): Hadoop 0.20.2, HBase 0.20.6 1 * namenode & hmaster & zookeeper 3… The hfile.block.cache.size = 0 performance is better than default(0.2) in random read? Is it possibl October 20, 2010 10:19:49 PM Hi all, I run my performance testing in random read, but I got the hfile.block.cache.size = 0 performance is better than default, Is it possible? My cluster (4 nodes): Hadoop 0.20.2, HBase 0.20.6 1 * namenode & hmaster & zookeeper 3… Improve read/write-concurrency September 7, 2010 04:09:42 AM Hi, is it correct that mongodb can only do one write in parallel and during a write no reads are allowed? Is the main reason for this limitation that the implementation of btree can not process concurrent reads and writes? ciao.hans. Rails + Amazon RDS : latency issues May 9, 2011 Hello I have an app whose database is being migrated to amazon RDS. I experienced a significant drop of performance, due to the latency of the… What latency can I expect when using MongoHQ from an external web server February 21, 2011 Does anyone have advice to offer regarding using a hosted DB solution, specifically MongoDB, with a web server. Specifically: Is the latency… WebException with SecureChannelFailure in high latency situation February 28, 2011 Hello, I have a .NET 3.5 application, client of some REST services, and deployed in networks having high latencies (ping time > 300 ms). In that… Latency time to sometimes load css or js file to 5s on localhost March 27, 2011 I use windows 7 64 bit + xampp 1.74 (apache) You can see in this picture: http://www.pixhost.org/show/2206/6438394_capture.png all that files is on… MySQL: How to retrieve a random row or multiple random rows? January 3, 2011 I have a MySQL database table that stores the URLs of photos. I need to pull 5 random records from the database of a particular type. I can pull 5… Apache mysql localhost latency delay problem. May 20, 2011 When i'm connecting to the internet and surf my localhost website "http://localhost". It takes aroud 2-5secs waiting for localhost. When i… MySql : how can I implement a sort of "read/not read yet" topics? January 28, 2011 Hi. 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The idea is that they have a kind… How do I improve my parsing technique? March 7, 2011 I am writing a pythonic parser for a custom language and as of now I have something like this: re1 = re.compile(r"...") re2 = re.compile(r"...") re3… | |||||
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