cassandra

Cassandra: NoSpamLogger log Maximum memory usage reached

由 安稳与你 提交于 2021-01-27 04:22:36
问题 Every 15 min I see this log entry: 2018-07-30 10:29:57,529 INFO [pool-1-thread-2] NoSpamLogger.java:91 log Maximum memory usage reached (512.000MiB), cannot allocate chunk of 1.000MiB I´ve been reading through this Question, but I cant see anything wrong with my tables: NoSpamLogger.java Maximum memory usage reached Cassandra I have 4 large tables: iot_data/derived_device_data histograms Percentile SSTables Write Latency Read Latency Partition Size Cell Count (micros) (micros) (bytes) 50% 0

Cassandra: NoSpamLogger log Maximum memory usage reached

由 扶醉桌前 提交于 2021-01-27 04:22:31
问题 Every 15 min I see this log entry: 2018-07-30 10:29:57,529 INFO [pool-1-thread-2] NoSpamLogger.java:91 log Maximum memory usage reached (512.000MiB), cannot allocate chunk of 1.000MiB I´ve been reading through this Question, but I cant see anything wrong with my tables: NoSpamLogger.java Maximum memory usage reached Cassandra I have 4 large tables: iot_data/derived_device_data histograms Percentile SSTables Write Latency Read Latency Partition Size Cell Count (micros) (micros) (bytes) 50% 0

Why secondary indexes are less efficient in Cassandra?

由 柔情痞子 提交于 2021-01-24 07:06:08
问题 I read in Cassandra documentation that creating secondary index is less efficient as because in worst case it need to touch all nodes in order to find out the data of that non-key column. But my doubt is even if we do not create secondary index, then also it will have to touch all nodes (in worst case) and find out where that particular row with this non-key column value resides. Note: Yeah, I understand that it is possible that if the cardinality is high then the secondary index will contain

NoHostAvailable error in cqlsh console

由 青春壹個敷衍的年華 提交于 2021-01-22 08:02:14
问题 I was able to get rid of this error later but i am not sure what i did is correct. 1 ) CREATE KEYSPACE myKeySpace WITH replication = {'class': 'NetworkTopologyStrategy', 'dc1': '1', 'dc2': '2'} AND durable_writes = true; Execute create table and select table after this. This throws "NoHostAvailable:" error in the console. 2 ) If I change the create statement to the below one, the select query works. CREATE KEYSPACE myKeySpace WITH replication = {'class': 'NetworkTopologyStrategy',

NoHostAvailable error in cqlsh console

由 巧了我就是萌 提交于 2021-01-22 08:00:57
问题 I was able to get rid of this error later but i am not sure what i did is correct. 1 ) CREATE KEYSPACE myKeySpace WITH replication = {'class': 'NetworkTopologyStrategy', 'dc1': '1', 'dc2': '2'} AND durable_writes = true; Execute create table and select table after this. This throws "NoHostAvailable:" error in the console. 2 ) If I change the create statement to the below one, the select query works. CREATE KEYSPACE myKeySpace WITH replication = {'class': 'NetworkTopologyStrategy',

com.datastax.driver.core.exceptions.BusyPoolException

由 …衆ロ難τιáo~ 提交于 2021-01-20 04:36:44
问题 Whenever I insert data in table in Cassandra, more than 1000 and fetching the data by id, it throws the following exception: com.datastax.driver.core.exceptions.NoHostAvailableException: All host(s) tried for query failed (tried: localhost/127.0.0.1:9042 (com.datastax.driver.core.exceptions.BusyPoolException: [localhost/127.0.0.1] Pool is busy (no available connection and the queue has reached its max size 256))) at com.datastax.driver.core.RequestHandler.reportNoMoreHosts(RequestHandler.java

com.datastax.driver.core.exceptions.BusyPoolException

由 谁都会走 提交于 2021-01-20 04:32:49
问题 Whenever I insert data in table in Cassandra, more than 1000 and fetching the data by id, it throws the following exception: com.datastax.driver.core.exceptions.NoHostAvailableException: All host(s) tried for query failed (tried: localhost/127.0.0.1:9042 (com.datastax.driver.core.exceptions.BusyPoolException: [localhost/127.0.0.1] Pool is busy (no available connection and the queue has reached its max size 256))) at com.datastax.driver.core.RequestHandler.reportNoMoreHosts(RequestHandler.java

详谈分布式最终一致性

由 北慕城南 提交于 2021-01-14 13:34:59
“什么是分布式系统？这取决于看系统的角度。对于坐在键盘前使用IBM个人电脑的人来说，电脑不是一个分布式的系统。但对于在电脑主板上趴着的虫子来说，这台电脑就是一个分布式系统。” —— Leslie Lamport 引言 分布式一致性问题随处可见，任何一个实体/联接模型，都可能存在分布式一致性问题。如果把单机拆开来看，CPU、内存、I/O设备组成的机箱本身就是一个小型的分布式系统，需要确保对这个系统操作的最终一致性。幸运的是这部分工作已经交给操作系统和数据库软件来帮我们完成。而在大型分布式企业级应用中，分布式最终一致性方案需要根据系统自身特点量身定制，是系统设计的重点。近年来随着沪江业务的快速增长和微服务治理推广，本地ACID事务早已不能满足业务和系统的发展需求。大部分业务流程都需要跨多微服务的调用来协作完成，并且要求系统确保分布式最终一致性。 可以选择分布式事务框架方案，目前主流的分布式事务框架大致可分为3类实现 : 基于XA协议的两阶段提交(2PC)方案 基于支付宝最早提出的TCC(Try、Confirm、Cancel)方案 基于ebay最早提出的消息队列异步确保方案 此外还有较轻的解决方案，业务系统可以根据自身需要，选择通过幂等/重试、状态机、恢复日志、异步校验等技术来确保最终一致性。 重型武器 采用分布式事务框架的方案，最终一致性由分布式事务框架保证

Apache Flink 零基础入门（二十）Flink connector

由 ￡可爱￡侵袭症＋ 提交于 2021-01-14 03:55:05
内置source和sink 内置source包括从文件读取，从文件夹读取，从socket中读取、从集合或者迭代器中读取。内置的sink包括写文件、控制台输出、socket 内置connectors Apache Kafka (source/sink) Apache Cassandra (sink) Amazon Kinesis Streams (source/sink) Elasticsearch (sink) Hadoop FileSystem (sink) RabbitMQ (source/sink) Apache NiFi (source/sink) Twitter Streaming API (source) HDFS Connector 这个connector提供了一个sink，可以写分区到任何一个文件系统（只要支持hadoop filesystem就可以）。 来源： oschina 链接： https://my.oschina.net/u/946962/blog/3106670

使用Lens管理多云Kubernetes

由 ↘锁芯ラ 提交于 2021-01-12 13:16:56
大量报告不断表明，今天的企业将混合和多云作为其首选的IT基础设施部署模式。根据IDG的一项 调查 ，超过一半（55%）的组织目前使用多个公有云，21%的组织说他们使用三个或更多的公有云。 云计算调查： https://resources.idg.com/download/2020-cloud-computing-executive-summary-rl 本文来自于CNCF： https://www.cncf.io/blog/2021/01/06/multicloud-kubernetes-management-with-lens/ 更多参考： kubernetes for china Kubernetes知识体系-从入门到精通 Kubernetes知识体系-架构图版 Kubernetes 1.20.0高可用集群快速升级及扩容 Kubernetes 1.20：最优秀、美妙、酷的版本 使用Kubeadm Upgrade更新Kubernetes集群的过程 使用kubeadm部署高可用Kubernetes 1.17.0 Kubernetes 多集群管理平台-wayne实践 KubeSphere®️ 容器集群管理平台 随着开发人员逐渐适应构建和发布容器，Kubernetes已成为容器编排的首选。 组织为什么要跨多个云供应商部署Kubernetes有很多原因： 云爆发 在多云基础设施中，“爆发
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