Oh! Thanks.
journalMaxGroupWaitMSec=2 every addEntry request will wait this MSec? Thanks. Thanks. Thanks. Thanks. 原始邮件 发件人:[email protected] 收件人:[email protected] 发送时间:2018年7月6日(周五) 17:56 主题:Re: latency of bookkeeper Can I close the WAL if i can tolerate any enries lost. if WAL can be closed, i can use bookkeeper in different scenes. 原始邮件 发件人:Sijie [email protected] 收件人:[email protected] 发送时间:2018年7月6日(周五) 16:11 主题:Re: latency of bookkeeper I think your question is a bit not clear, latency and throughput are two kind of different metrics. Your question seems to be asking for high throughput. Anyway, I will try to explain the performance tradeoff between latency and throughput and hope that helps. Bookkeeper by default fsync the data to disks. It does 1ms group commit by default to keep a good tradeoff between throughput and latency. 1) if you are using synchronous adds, since you are blocking on waiting write response, your single thread throughput will be limited by the group commit interval. You can use multiple threads to improve throughput, since multiple writes will be grouped together writing to disks, you will get as lower latency as your group commit interval for your writes. 2) if your application can leverage asynchronous adds, you should consider using asynchronous apis. It will offer you the best latency while be able to achieve high throughput. 3) the latency will eventually be dominated by your disk fsync latency. SSD or HDD with battery will have good fsync latency (about half millisecond). However if your disk is not as good to provide such lower latency, you can consider disable fsync and rely on replication to achieve durability.https://github.com/apache/bookkeeper/blob/master/conf/bk_server.conf#L309 Hope this helps. On Thu, Jul 5, 2018 at 11:46 PM [email protected] [email protected] wrote: Hi I try to use bookkeeper. i care latency of write. so start a test in single thread. get 400 ops/s in double SSD. how to improve performance to get the low-latency. Thanks. [email protected]
