etcd的dbsize引起的集群故障

故障现象

k8s集群不能访问，具体表现kubectl命令不能使用。

思路

检查apiserver服务状态，检查etcd集群状态中errors列中存在一个alarm:NOSPACE的告警

解决&分析

具体表现
在这里插入图片描述
恢复使用第一，先尝试解除告警看能否恢复

etcdctl --endpoints=https://192.168.1.15:2379 --cacert=/etc/kubernetes/pki/etcd/ca.crt --cert=/etc/kubernetes/pki/etcd/server.crt --key=/etc/kubernetes/pki/etcd/server.key alarm disarm

验证集群中是否还有alarm信息

etcdctl --endpoints=https://192.168.1.15:2379 --cacert=/etc/kubernetes/pki/etcd/ca.crt --cert=/etc/kubernetes/pki/etcd/server.crt --key=/etc/kubernetes/pki/etcd/server.key alarm list

可以愉快的访问集群了。

继续观察 15节点的DB SIZE达到2.1GB了，其它两个节点正常
使用资料中的方法通过执行压缩节点1的数据释放blobDB并对数据库文件进行defragmentation碎片整理，结果是节点无法执行压缩及无法同步新key，随便整理后也不行，节点1和另外两个节点的reversion落后太多，导致执行compaction时报错：Got: Error from server: etcdserver: mvcc: required revision is a future revision，且此报错网上非常少，资料上一般到这里就让继续清理另外两台机器上的dbsize了，但并不能解决etcd1上的问题，我这边使用将节点1踢出集群并通过正常节点的snapshot来重新加入集群，使得三节点的历史数据保持一致

压缩并释放

通过endpoints status -w table看到的字段中的RAFT INDEX和RAFT APPLIED INDEX字段集群中的节点是相同的，但 -w json才能看到每个节点上同步到的最新的reversion是多少

etcdctl  --endpoints=https://192.168.1.15:2379,https://192.168.1.17:2379,https://192.168.1.38:2379 --cacert=/etc/kubernetes/pki/etcd/ca.crt --cert=/etc/kubernetes/pki/etcd/server.crt --key=/etc/kubernetes/pki/etcd/server.key endpoint status --write-out="json"
[{"Endpoint":"https://192.168.1.15:2379","Status":{"header":{"cluster_id":3483896258597590173,"member_id":14117095307229358704,"revision":542770334,"raft_term":420},"version":"3.5.0","dbSize":2146328576,"leader":17230009819260537482,"raftIndex":664811268,"raftTerm":420,"raftAppliedIndex":664811268,"dbSizeInUse":2146320384}},{"Endpoint":"https://192.168.1.17:2379","Status":{"header":{"cluster_id":3483896258597590173,"member_id":17230009819260537482,"revision":582270095,"raft_term":420},"version":"3.5.0","dbSize":718491648,"leader":17230009819260537482,"raftIndex":664811268,"raftTerm":420,"raftAppliedIndex":664811268,"dbSizeInUse":69287936}},{"Endpoint":"https://192.168.1.38:2379","Status":{"header":{"cluster_id":3483896258597590173,"member_id":9235900205731567691,"revision":582270095,"raft_term":420},"version":"3.5.0","dbSize":718491648,"leader":17230009819260537482,"raftIndex":664811268,"raftTerm":420,"raftAppliedIndex":664811268,"dbSizeInUse":69283840}}]

etcdctl --endpoints=https://192.168.1.15:2379 --cacert=/etc/kubernetes/pki/etcd/ca.crt --cert=/etc/kubernetes/pki/etcd/server.crt --key=/etc/kubernetes/pki/etcd/server.key compact 542770334
compacted revision 542770334

碎片整理(建议稍等一会再执行，否则会报错)
{“level”:“warn”,“ts”:“2024-12-09T10:08:09.160931+0800”,“caller”:“clientv3/retry_interceptor.go:62”,“msg”:“retrying of unary invoker failed”,“target”:“passthrough:///https://192.168.1.15:2379”,“attempt”:0,“error”:“rpc error: code = DeadlineExceeded desc = context deadline exceeded”}
Failed to defragment etcd member[https://192.168.1.15:2379] (context deadline exceeded)

etcdctl --endpoints=https://192.168.1.15:2379 --cacert=/etc/kubernetes/pki/etcd/ca.crt --cert=/etc/kubernetes/pki/etcd/server.crt --key=/etc/kubernetes/pki/etcd/server.key defrag

Finished defragmenting etcd member[https://192.168.1.15:2379]

etcd1日志输出

{"level":"info","ts":"2024-12-09T02:15:18.829Z","caller":"v3rpc/maintenance.go:89","msg":"starting defragment"}
{"level":"info","ts":"2024-12-09T02:15:18.832Z","caller":"backend/backend.go:479","msg":"defragmenting","path":"/var/lib/etcd/member/snap/db","current-db-size-bytes":1039929344,"current-db-size":"1.0 GB","current-db-size-in-use-bytes":124841984,"current-db-size-in-use":"125 MB"}
{"level":"info","ts":"2024-12-09T02:15:19.759Z","caller":"backend/backend.go:537","msg":"finished defragmenting directory","path":"/var/lib/etcd/member/snap/db","current-db-size-bytes-diff":-915320832,"current-db-size-bytes":124608512,"current-db-size":"125 MB","current-db-size-in-use-bytes-diff":-253952,"current-db-size-in-use-bytes":124588032,"current-db-size-in-use":"125 MB","took":"929.794141ms"}
{"level":"info","ts":"2024-12-09T02:15:19.759Z","caller":"v3rpc/maintenance.go:95","msg":"finished defragment"}

清理后节点信息

root@dev-k8s-master03:~# etcdctl  --endpoints=https://192.168.1.15:2379,https://192.168.1.17:2379,https://192.168.1.38:2379 --cacert=/etc/kubernetes/pki/etcd/ca.crt --cert=/etc/kubernetes/pki/etcd/server.crt --key=/etc/kubernetes/pki/etcd/server.key endpoint status --write-out="table"
+---------------------------+------------------+---------+---------+-----------+------------+-----------+------------+--------------------+--------+
|         ENDPOINT          |        ID        | VERSION | DB SIZE | IS LEADER | IS LEARNER | RAFT TERM | RAFT INDEX | RAFT APPLIED INDEX | ERRORS |
+---------------------------+------------------+---------+---------+-----------+------------+-----------+------------+--------------------+--------+
| https://192.168.1.15:2379 | c3e9ff62e7bd6a70 |   3.5.0 |  126 MB |     false |      false |       420 |  664830103 |          664830103 |        |
| https://192.168.1.17:2379 | ef1d4aa461844a8a |   3.5.0 |  718 MB |      true |      false |       420 |  664830103 |          664830103 |        |
| https://192.168.1.38:2379 | 802c824d9f96584b |   3.5.0 |  718 MB |     false |      false |       420 |  664830103 |          664830103 |        |
+---------------------------+------------------+---------+---------+-----------+------------+-----------+------------+--------------------+--------+

重新加入集群

root@dev-k8s-master03:~# etcdctl --endpoints=https://192.168.1.38:2379 --cacert=/etc/kubernetes/pki/etcd/ca.crt --cert=/etc/kubernetes/pki/etcd/server.crt --key=/etc/kubernetes/pki/etcd/server.key snapshot save /tmp/etcd-snapshot-`date +%F-%T`.db
{"level":"info","ts":1733714785.0831125,"caller":"snapshot/v3_snapshot.go:119","msg":"created temporary db file","path":"/tmp/etcd-snapshot-2024-12-09-11:26:25.db.part"}
{"level":"info","ts":"2024-12-09T11:26:25.088262+0800","caller":"clientv3/maintenance.go:200","msg":"opened snapshot stream; downloading"}
{"level":"info","ts":1733714785.0883157,"caller":"snapshot/v3_snapshot.go:127","msg":"fetching snapshot","endpoint":"https://192.168.1.38:2379"}
{"level":"info","ts":"2024-12-09T11:26:29.600605+0800","caller":"clientv3/maintenance.go:208","msg":"completed snapshot read; closing"}
{"level":"info","ts":1733714789.8358912,"caller":"snapshot/v3_snapshot.go:142","msg":"fetched snapshot","endpoint":"https://192.168.1.38:2379","size":"718 MB","took":4.752708895}
{"level":"info","ts":1733714789.836093,"caller":"snapshot/v3_snapshot.go:152","msg":"saved","path":"/tmp/etcd-snapshot-2024-12-09-11:26:25.db"}
Snapshot saved at /tmp/etcd-snapshot-2024-12-09-11:26:25.db

添加集群

(base) root@dev-k8s-master03:/etc/kubernetes/manifests# etcdctl --cacert=/etc/kubernetes/pki/etcd/ca.crt --cert=/etc/kubernetes/pki/etcd/server.crt --key=/etc/kubernetes/pki/etcd/server.key member add dev-k8s-master01 --peer-urls=https://192.168.1.15:2380
Member e84022fd6cf784bd added to cluster 305949305005949d

ETCD_NAME="dev-k8s-master01"
ETCD_INITIAL_CLUSTER="dev-k8s-master03=https://192.168.1.38:2380,dev-k8s-master01=https://192.168.1.15:2380,dev-k8s-master02=https://192.168.1.17:2380"
ETCD_INITIAL_ADVERTISE_PEER_URLS="https://192.168.1.15:2380"
ETCD_INITIAL_CLUSTER_STATE="existing"

在节点1执行操作

mv /var/lib/etcd /tmp/
root@dev-k8s-master01:/etc/kubernetes/manifests# etcdctl --endpoints=192.168.1.15:2379 snapshot restore /tmp/etcd-snapshot-2024-12-09-11:26:25.db --data-dir=/var/lib/etcd/     --name=dev-k8s-master01     --initial-cluster dev-k8s-master05=dev-k8s-master01=https://192.168.1.15:2380,dev-k8s-master03=https://192.168.1.38:2380,dev-k8s-master02=https://192.168.1.17:2380     --initial-cluster-token etcd-cluster-1     --initial-advertise-peer-urls https://192.168.1.15:2380
{"level":"info","ts":1733716067.1317353,"caller":"snapshot/v3_snapshot.go:306","msg":"restoring snapshot","path":"/tmp/etcd-snapshot-2024-12-09-11:26:25.db","wal-dir":"/var/lib/etcd/member/wal","data-dir":"/var/lib/etcd/","snap-dir":"/var/lib/etcd/member/snap"}
{"level":"info","ts":1733716070.3973181,"caller":"mvcc/kvstore.go:388","msg":"restored last compact revision","meta-bucket-name":"meta","meta-bucket-name-key":"finishedCompactRev","restored-compact-revision":582286281}
{"level":"info","ts":1733716070.4496565,"caller":"membership/cluster.go:392","msg":"added member","cluster-id":"a9e5595b49b6f283","local-member-id":"0","added-peer-id":"5c03789b52368037","added-peer-peer-urls":["https://192.168.1.15:2380"]}
{"level":"info","ts":1733716070.4497328,"caller":"membership/cluster.go:392","msg":"added member","cluster-id":"a9e5595b49b6f283","local-member-id":"0","added-peer-id":"784dac5337680b08","added-peer-peer-urls":["https://192.168.1.17:2380"]}
{"level":"info","ts":1733716070.4497697,"caller":"membership/cluster.go:392","msg":"added member","cluster-id":"a9e5595b49b6f283","local-member-id":"0","added-peer-id":"aed753eb6f15876c","added-peer-peer-urls":["https://192.168.1.38:2380"]}
{"level":"info","ts":1733716070.449801,"caller":"membership/cluster.go:392","msg":"added member","cluster-id":"a9e5595b49b6f283","local-member-id":"0","added-peer-id":"d71e7a79c5fb9cce","added-peer-peer-urls":["https://192.168.0.90:2380"]}
{"level":"info","ts":1733716070.4569333,"caller":"snapshot/v3_snapshot.go:326","msg":"restored snapshot","path":"/tmp/etcd-snapshot-2024-12-09-11:26:25.db","wal-dir":"/var/lib/etcd/member/wal","data-dir":"/var/lib/etcd/","snap-dir":"/var/lib/etcd/member/snap"}

日志中有加入集群的详细过程，此处不再截取
验证状态

(base) root@dev-k8s-master03:/etc/kubernetes/manifests# etcdctl  --endpoints=https://192.168.1.15:2379,https://192.168.1.17:2379,https://192.168.1.38:2379 --cacert=/etc/kubernetes/pki/etcd/ca.crt --cert=/etc/kubernetes/pki/etcd/server.crt --key=/etc/kubernetes/pki/etcd/server.key endpoint status --write-out="table"
+---------------------------+------------------+---------+---------+-----------+------------+-----------+------------+--------------------+--------+
|         ENDPOINT          |        ID        | VERSION | DB SIZE | IS LEADER | IS LEARNER | RAFT TERM | RAFT INDEX | RAFT APPLIED INDEX | ERRORS |
+---------------------------+------------------+---------+---------+-----------+------------+-----------+------------+--------------------+--------+
| https://192.168.1.15:2379 | e84022fd6cf784bd |   3.5.0 |  718 MB |     false |      false |       420 |  664841654 |          664841654 |        |
| https://192.168.1.17:2379 | ef1d4aa461844a8a |   3.5.0 |  718 MB |      true |      false |       420 |  664841654 |          664841654 |        |
| https://192.168.1.38:2379 | 802c824d9f96584b |   3.5.0 |  718 MB |     false |      false |       420 |  664841654 |          664841654 |        |
+---------------------------+------------------+---------+---------+-----------+------------+-----------+------------+--------------------+--------+

后续

查看etcd启动日志发现虽然开启了auto-compaction-mode和auto-compaction-retention，但retention的值为0，代表不生效，三个节点都要启用

auto-compaction-mode=periodic
表示时间间隔（如 1h、30m、10s），即 etcd 每隔多长时间对数据进行一次压缩。
例如，设置为 --auto-compaction-retention=1h 意味着每小时自动执行一次 compaction，清理一小时前的历史数据。
当 --auto-compaction-mode=revision
–auto-compaction-retention 表示保留多少个修订版本（revision）的历史记录。
例如，–auto-compaction-retention=1000 表示只保留最近 1000 个 revision 的历史数据，超过这个修订范围的历史版本将被压缩清理。

更改自动压缩的参数使etcd自动删除过期的key，注意：这样仍然不会释放物理空间的blobDB size，仍需手动释放。

启用前etcd日志输出

kubectl logs -f etcd-dev-k8s-master02 |grep -i compaction
{"level":"info","ts":"2024-12-09T01:35:20.425Z","caller":"embed/etcd.go:307","msg":"starting an etcd server","etcd-version":"3.5.0","git-sha":"946a5a6f2","go-version":"go1.16.3","go-os":"linux","go-arch":"amd64","max-cpu-set":4,"max-cpu-available":4,"member-initialized":true,"name":"dev-k8s-master02","data-dir":"/var/lib/etcd","wal-dir":"","wal-dir-dedicated":"","member-dir":"/var/lib/etcd/member","force-new-cluster":false,"heartbeat-interval":"100ms","election-timeout":"1s","initial-election-tick-advance":true,"snapshot-count":10000,"snapshot-catchup-entries":5000,"initial-advertise-peer-urls":["https://192.168.1.17:2380"],"listen-peer-urls":["https://192.168.1.17:2380"],"advertise-client-urls":["https://192.168.1.17:2379"],"listen-client-urls":["https://127.0.0.1:2379","https://192.168.1.17:2379"],"listen-metrics-urls":["http://127.0.0.1:2381"],"cors":["*"],"host-whitelist":["*"],"initial-cluster":"","initial-cluster-state":"existing","initial-cluster-token":"","quota-size-bytes":2147483648,"pre-vote":true,"initial-corrupt-check":false,"corrupt-check-time-interval":"0s","auto-compaction-mode":"periodic","auto-compaction-retention":"0s","auto-compaction-interval":"0s","discovery-url":"","discovery-proxy":"","downgrade-check-interval":"5s"}

更改etcd static manifest文件

root@dev-k8s-master03:/etc/kubernetes/manifests# grep compaction /etc/kubernetes/manifests/etcd.yaml 
    - --auto-compaction-retention=10h

会触发pod自动重建，验证

(base) root@dev-k8s-master03:/etc/kubernetes/manifests# kubectl logs -f etcd-dev-k8s-master03 |grep -i compaction
{"level":"info","ts":"2024-12-09T07:04:26.400Z","caller":"etcdmain/etcd.go:72","msg":"Running: ","args":["etcd","--advertise-client-urls=https://192.168.1.38:2379","--cert-file=/etc/kubernetes/pki/etcd/server.crt","--client-cert-auth=true","--data-dir=/var/lib/etcd","--initial-advertise-peer-urls=https://192.168.1.38:2380","--initial-cluster=dev-k8s-master05=https://192.168.0.90:2380,dev-k8s-master01=https://192.168.1.15:2380,dev-k8s-master03=https://192.168.1.38:2380,dev-k8s-master02=https://192.168.1.17:2380","--initial-cluster-state=existing","--key-file=/etc/kubernetes/pki/etcd/server.key","--listen-client-urls=https://127.0.0.1:2379,https://192.168.1.38:2379","--listen-metrics-urls=http://127.0.0.1:2381","--listen-peer-urls=https://192.168.1.38:2380","--name=dev-k8s-master03","--peer-cert-file=/etc/kubernetes/pki/etcd/peer.crt","--peer-client-cert-auth=true","--peer-key-file=/etc/kubernetes/pki/etcd/peer.key","--peer-trusted-ca-file=/etc/kubernetes/pki/etcd/ca.crt","--snapshot-count=10000","--auto-compaction-retention=10h","--trusted-ca-file=/etc/kubernetes/pki/etcd/ca.crt"]}
{"level":"info","ts":"2024-12-09T07:04:26.400Z","caller":"embed/etcd.go:307","msg":"starting an etcd server","etcd-version":"3.5.0","git-sha":"946a5a6f2","go-version":"go1.16.3","go-os":"linux","go-arch":"amd64","max-cpu-set":8,"max-cpu-available":8,"member-initialized":true,"name":"dev-k8s-master03","data-dir":"/var/lib/etcd","wal-dir":"","wal-dir-dedicated":"","member-dir":"/var/lib/etcd/member","force-new-cluster":false,"heartbeat-interval":"100ms","election-timeout":"1s","initial-election-tick-advance":true,"snapshot-count":10000,"snapshot-catchup-entries":5000,"initial-advertise-peer-urls":["https://192.168.1.38:2380"],"listen-peer-urls":["https://192.168.1.38:2380"],"advertise-client-urls":["https://192.168.1.38:2379"],"listen-client-urls":["https://127.0.0.1:2379","https://192.168.1.38:2379"],"listen-metrics-urls":["http://127.0.0.1:2381"],"cors":["*"],"host-whitelist":["*"],"initial-cluster":"","initial-cluster-state":"existing","initial-cluster-token":"","quota-size-bytes":2147483648,"pre-vote":true,"initial-corrupt-check":false,"corrupt-check-time-interval":"0s","auto-compaction-mode":"periodic","auto-compaction-retention":"10h0m0s","auto-compaction-interval":"10h0m0s","discovery-url":"","discovery-proxy":"","downgrade-check-interval":"5s"}
# 已经触发一次压缩
{"level":"info","ts":"2024-12-09T07:08:13.712Z","caller":"mvcc/kvstore_compaction.go:57","msg":"finished scheduled compaction","compact-revision":582337465,"took":"128.526142ms"}

还可以扩大etcd的blobsize。

reference

https://etcd.io/docs/v3.4/op-guide/maintenance/

本文来自互联网用户投稿，该文观点仅代表作者本人，不代表本站立场。本站仅提供信息存储空间服务，不拥有所有权，不承担相关法律责任。如若转载，请注明出处：/a/933875.html

如若内容造成侵权/违法违规/事实不符，请联系我们进行投诉反馈qq邮箱809451989@qq.com，一经查实，立即删除！

相关文章

Redis性能优化18招

Redis性能优化18招

Redis性能优化的18招 目录 前言选择合适的数据结构避免使用过大的key和value[使用Redis Pipeline](#使用Redis Pipeline)控制连接数量合理使用过期策略使用Redis集群充分利用内存优化使用Lua脚本监控与调优避免热点key使用压缩使用Geo位置功能控制数据的持久化尽量减少事务使…
阅读更多...
Docker 安装 Yapi

Docker 安装 Yapi

Docker 安装系列 Docker已安装。 1、场景Yapi使用的MongoDB用户信息 1.1 创建自定义 Docker 网络 首先，创建一个自定义的 Docker 网络，以便 MongoDB 和 YApi 容器可以相互通信 [rootflexusx-328569 data]# docker network create yapi-networ…
阅读更多...
深度学习（2）前向传播与反向传播

深度学习（2）前向传播与反向传播

这一次我们重点讲解前向传播与反向传播，对这里还是有点糊涂 前向传播（Forward Propagation）和反向传播（Backward Propagation）是深度学习中神经网络训练的核心过程。它们分别负责计算神经网络的输出以及更新神经网络的…
阅读更多...
Mock神器：Easy-Mock 私有化部署及使用介绍

Mock神器：Easy-Mock 私有化部署及使用介绍

在现代前后端分离的开发模式中，后端接口的数据模拟是一个常见且必要的需求。尤其是在后端接口尚未开发完成时，前端开发需要依赖模拟数据进行开发与测试。Easy-Mock 是一个非常流行的开源工具（虽然它已经停止更新好长时间了）&#…
阅读更多...
个人IP建设：简易指南

个人IP建设：简易指南

许多个体创业者面临的一个关键挑战是如何为其企业创造稳定的需求。 作为个体创业者，您无法使用营销团队，因此许多人通过推荐和他们的网络来产生需求。因此，扩大您的网络是发展您的业务和产生持续需求的最佳策略。 这就是个人IP和品牌发挥作…
阅读更多...
二一(GIT4)、echarts(地图)、黑马就业数据平台(学生页-增 删 改)

二一(GIT4)、echarts(地图)、黑马就业数据平台(学生页-增 删 改)

1. echarts 地图 echarts社区：makeapie echarts社区图表可视化案例 社区模板代码地址：自定义 tooltip-轮播 - category-work,series-map地图,tooltip提示框,visualMap视觉映射 - makeapie echarts社区图表可视化案例 // todo: 籍贯分布 地图 function…
阅读更多...
iPhone 17 Air基本确认，3个大动作

iPhone 17 Air基本确认，3个大动作

近段时间，果粉圈都在讨论一个尚未发布的新品：iPhone 17 Air，苹果又要来整新活了。 从供应链消息来看，iPhone 17 Air本质上是Plus的替代品，主要是在维持“大屏”这一卖点的同时，增加了“轻薄”属性&#xff…
阅读更多...
数据结构之初始二叉树（1）

数据结构之初始二叉树（1）

找往期文章包括但不限于本期文章中不懂的知识点： 个人主页：我要学编程(ಥ_ಥ)-CSDN博客 所属专栏：数据结构（Java版） 目录 树型结构 树的概念 与树的有关概念 树的表示形式 树的应用 二叉树 概念 两种特殊的…
阅读更多...
RabbitMQ七种工作模式之 RPC通信模式, 发布确认模式

RabbitMQ七种工作模式之 RPC通信模式, 发布确认模式

文章目录 六. RPC(RPC通信模式)客户端服务端 七. Publisher Confirms(发布确认模式)1. Publishing Messages Individually(单独确认)2. Publishing Messages in Batches(批量确认)3. Handling Publisher Confirms Asynchronously(异步确认) 六. RPC(RPC通信模式) 客⼾端发送消息…
阅读更多...
深入理解 SQL 注入：原理、攻击流程与防御措施

深入理解 SQL 注入：原理、攻击流程与防御措施

深入理解 SQL 注入：原理、攻击流程与防御措施 在当今数字化的时代，数据安全已成为每个企业和开发者必须面对的重要课题。SQL 注入（SQL Injection）作为一种常见的网络攻击方式，给无数企业带来了巨大的损失。本文将深入…
阅读更多...
【项目实战】基于python+爬虫的电影数据分析及可视化系统

【项目实战】基于python+爬虫的电影数据分析及可视化系统

注意：该项目只展示部分功能，如需了解，文末咨询即可。 本文目录 1.开发环境2 系统设计 2.1 设计背景2.2 设计内容 3 系统页面展示 3.1 用户页面3.2 后台页面3.3 功能展示视频 4 更多推荐5 部分功能代码 5.1 爬虫代码5.2 电影信息代码 1.开发环…
阅读更多...
JCR一区牛顿-拉夫逊优化算法+分解对比！VMD-NRBO-Transformer-BiLSTM多变量时序光伏功率预测

JCR一区牛顿-拉夫逊优化算法+分解对比！VMD-NRBO-Transformer-BiLSTM多变量时序光伏功率预测

JCR一区牛顿-拉夫逊优化算法分解对比！VMD-NRBO-Transformer-BiLSTM多变量时序光伏功率预测 目录 JCR一区牛顿-拉夫逊优化算法分解对比！VMD-NRBO-Transformer-BiLSTM多变量时序光伏功率预测预测效果基本介绍程序设计参考资料 预测效果 基本介绍 1.中科院…
阅读更多...
深入探索 Compose 渲染流程：从 UI 树到 Skia 绘制的实现解析

深入探索 Compose 渲染流程：从 UI 树到 Skia 绘制的实现解析

文章目录 前言Compose 渲染流程概述1. Compose 解析1.1 Compose 声明性 UI1.2 Compose 编译1.2.1 Compose 编译概述1.2.2 代码示例1.2.3 编译过程细节 1.3 组合与重组合1.3.1 组合（Composition）1.3.2 重组合1.3.3 组合与重组合的区别1.3.4 组合与重组合的…
阅读更多...
数据结构排序算法详解

数据结构排序算法详解

数据结构排序算法详解 1、冒泡排序（Bubble Sort）2、选择排序（Selection Sort）2、插入排序（Insertion Sort）4、快速排序（Quick Sort） 1、冒泡排序（Bubble Sort&#xff09…
阅读更多...
命令模式的理解和实践

命令模式的理解和实践

在软件开发中，设计模式是开发者们经过长期实践总结出来的、可复用的解决方案，用于解决常见的设计问题。命令模式（Command Pattern）是行为型设计模式之一，它通过将一个请求封装成一个对象，从而允许用户用不同…
阅读更多...
【C++】关系操作符的全面解析与高级应用

【C++】关系操作符的全面解析与高级应用

博客主页： [小ᶻ☡꙳ᵃⁱᵍᶜ꙳] 本文专栏: C 文章目录 💯前言💯关系操作符1.关系操作符的分类与语义2.关系操作符的连用问题3.浮点数比较的精度问题问题示例解决方案 💯总结核心要点 💯小结 💯前言 在…
阅读更多...
python爬虫--某房源网站验证码破解

python爬虫--某房源网站验证码破解

文章目录 使用模块爬取目标验证码技术细节实现成果代码实现使用模块 requests请求模块 lxml数据解析模块 ddddocr光学识别 爬取目标 网站验证码破解思路是统一的，本文以城市列表为例 目标获取城市名以及城市连接，之后获取城市房源信息技术直接替换地址即可 验证码 技术…
阅读更多...
java+ssm+mysql校园物品租赁网

java+ssm+mysql校园物品租赁网

项目介绍： 使用javassmmysql开发的校园物品租赁网，系统包含管理员、用户角色，功能如下： 管理员：用户管理；物品管理（物品种类、物品信息、评论信息）；订单管理&#xff1…
阅读更多...
【JS】简单CSS简单JS写的上传进度条

【JS】简单CSS简单JS写的上传进度条

纯JS写的&#xff0c;简单的上传进度条&#xff0c;当上传的文件较大&#xff0c;加一个动态画面&#xff0c;就不会让人觉得出错了或网络卡了 <!DOCTYPE html> <html lang"en"><head><meta charset"UTF-8"><meta name"v…
阅读更多...
Oracle系统性能监控工具oswatcher演示

Oracle系统性能监控工具oswatcher演示

1、关于 OSW OSWatcher 的使用符合 Oracle 的标准许可条款&#xff0c;并且不需要额外的许可即可使用&#xff01;&#xff01;&#xff01;&#xff01; OSWatcher (oswbb) 是一种 UNIX shell 脚本的集合&#xff0c;主要用于收集和归档操作系统和网络的度量&#xff0c;以便…
阅读更多...
最新文章

Copyright @ 2022~2023