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df63692a18
Deploy Examination / deploy (push) Successful in 31s
Cover 9 subtopics from the computer networking documentation: - http-handshake: TCP/TLS/HTTP2/HTTP3 handshakes - http-connection-cost: connection resource overhead & million concurrency - connection-pooling: pool reuse, HTTP/1.1 vs HTTP/2 - http-keepalive: Keep-Alive principle, head-of-line blocking - keepalive-scenarios: when to enable/disable Keep-Alive - domain-sharding: HTTP/1.1 hack, HTTP/2 obsolescence - cdn: edge nodes, caching, DDoS protection - cors: same-origin policy, preflight requests - go-build-strip: -s -w flags, binary size optimization
209 lines
6.6 KiB
JSON
209 lines
6.6 KiB
JSON
{
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"topic": "domain-sharding",
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"type": "single_choice",
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"schema_version": "1.0.0",
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"generated": "2026-09-02T21:20:00+08:00",
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"questions": [
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{
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"id": "sc-001",
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"type": "single_choice",
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"difficulty": 2,
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"tags": [
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"域名分片",
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"浏览器限制"
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],
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"question": "浏览器对同一域名最多同时开多少个 TCP 连接？",
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"options": {
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"A": "2 个",
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"B": "4 个",
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"C": "6 个",
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"D": "10 个"
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},
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"answer": "C",
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"explanation": "浏览器对同一域名最多同时开 6 个 TCP 连接，这是浏览器厂商的经验值，不是协议规定。这个限制在 HTTP/2 时代已经过时。",
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"source": null,
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"related": []
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},
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{
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"id": "sc-002",
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"type": "single_choice",
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"difficulty": 3,
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"tags": [
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"域名分片",
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"原理"
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],
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"question": "域名分片的原理是什么？",
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"options": {
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"A": "增加服务器数量",
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"B": "用多个子域名指向同一服务器，每个域名都能开 6 个连接",
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"C": "使用 HTTP/2 协议",
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"D": "增大 TCP 窗口"
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},
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"answer": "B",
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"explanation": "域名分片用多个子域名指向同一台服务器，每个域名都能开 6 个连接。例如 3 个子域名 × 6 个连接 = 18 个并行连接。",
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"source": null,
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"related": []
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},
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{
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"id": "sc-003",
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"type": "single_choice",
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"difficulty": 3,
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"tags": [
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"域名分片",
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"代价"
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],
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"question": "域名分片的代价不包括以下哪项？",
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"options": {
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"A": "DNS 解析开销",
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"B": "TLS 握手开销",
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"C": "缓存碎片化",
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"D": "加密失败"
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},
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"answer": "D",
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"explanation": "域名分片的代价包括：DNS 解析开销（每个子域名都要单独解析，5-50ms）、TLS 握手开销（每个新域名要单独做 TLS 握手）、缓存碎片化（不同域名的缓存独立，不能共享）。",
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"source": null,
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"related": []
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},
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{
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"id": "sc-004",
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"type": "single_choice",
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"difficulty": 4,
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"tags": [
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"域名分片",
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"HTTP/2"
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],
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"question": "为什么 HTTP/2 不需要域名分片？",
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"options": {
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"A": "HTTP/2 支持更多连接",
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"B": "HTTP/2 的多路复用让一个 TCP 连接就能真正并行",
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"C": "HTTP/2 自动分片",
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"D": "HTTP/2 使用 UDP"
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},
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"answer": "B",
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"explanation": "HTTP/2 的多路复用让一个 TCP 连接就能真正并行处理多个请求/响应，不再需要多个 TCP 连接来并行，域名分片变成了负优化。",
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"source": null,
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"related": []
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},
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{
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"id": "sc-005",
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"type": "single_choice",
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"difficulty": 2,
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"tags": [
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"域名分片",
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"实现"
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],
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"question": "域名分片的实现方式是什么？",
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"options": {
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"A": "修改服务器配置",
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"B": "前端 HTML 里把资源 URL 的域名换掉",
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"C": "使用 CDN",
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"D": "修改 DNS 解析"
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},
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"answer": "B",
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"explanation": "域名分片只需在前端 HTML 里把资源 URL 的域名换掉（如 img1.example.com、img2.example.com），服务器端不用改动，所有子域名 DNS 解析到同一台机器就行。",
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"source": null,
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"related": []
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},
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{
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"id": "sc-006",
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"type": "single_choice",
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"difficulty": 4,
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"tags": [
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"域名分片",
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"缓存"
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],
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"question": "域名分片导致缓存碎片化的原因是什么？",
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"options": {
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"A": "缓存服务器过载",
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"B": "不同域名的缓存独立，不能共享",
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"C": "DNS 缓存过期",
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"D": "TLS 握手失败"
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},
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"answer": "B",
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"explanation": "域名分片导致缓存碎片化，因为不同域名的缓存独立，不能共享，可能重复下载相同资源。这是域名分片的主要代价之一。",
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"source": null,
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"related": []
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},
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{
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"id": "sc-007",
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"type": "single_choice",
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"difficulty": 3,
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"tags": [
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"域名分片",
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"数量"
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],
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"question": "域名分片的子域名数量一般是多少？",
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"options": {
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"A": "1-2 个",
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"B": "3-4 个",
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"C": "10-20 个",
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"D": "越多越好"
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},
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"answer": "B",
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"explanation": "域名分片的子域名数量一般 3-4 个就够了。过多子域名意味着更多 DNS 查询和 TLS 握手，反而拖慢加载速度。",
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"source": null,
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"related": []
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},
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{
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"id": "sc-008",
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"type": "single_choice",
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"difficulty": 2,
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"tags": [
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"域名分片",
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"DNS"
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],
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"question": "域名分片中，所有子域名的 DNS 解析应该指向什么？",
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"options": {
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"A": "不同的服务器",
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"B": "同一台机器",
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"C": "CDN 节点",
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"D": "负载均衡器"
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},
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"answer": "B",
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"explanation": "域名分片中所有子域名的 DNS 解析应该指向同一台机器，服务器端不用改动。前端只需把资源 URL 的域名换掉。",
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"source": null,
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"related": []
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},
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{
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"id": "sc-009",
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"type": "single_choice",
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"difficulty": 4,
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"tags": [
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"域名分片",
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"HTTP/2",
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"负优化"
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],
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"question": "在 HTTP/2 站点上使用域名分片会导致什么？",
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"options": {
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"A": "性能提升",
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"B": "负优化——多了 DNS 和 TLS 开销，还破坏了缓存统一性",
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"C": "没有影响",
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"D": "自动降级到 HTTP/1.1"
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},
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"answer": "B",
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"explanation": "HTTP/2 的多路复用让域名分片变成了负优化——多了 DNS 和 TLS 开销，还破坏了缓存统一性。如果站点已经上了 HTTP/2，应该去掉域名分片。",
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"source": null,
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"related": []
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},
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{
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"id": "sc-010",
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"type": "single_choice",
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"difficulty": 3,
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"tags": [
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"域名分片",
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"演进"
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],
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"question": "HTTP 连接复用的演进中，域名分片出现在哪个阶段？",
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"options": {
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"A": "HTTP/1.0 之前",
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"B": "HTTP/1.1 + Keep-Alive 之后，HTTP/2 之前",
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"C": "HTTP/2 之后",
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"D": "HTTP/3 之后"
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},
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"answer": "B",
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"explanation": "域名分片是 HTTP/1.1 时代的 hack，出现在 HTTP/1.1 + Keep-Alive 之后，HTTP/2 之前。HTTP/2 的多路复用从根本上解决了这个问题。",
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"source": null,
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"related": []
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}
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]
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} |