该数据集包含超过 45.5 亿条记录，因此除非你的资源能够承载如此规模的数据量，否则请谨慎直接复制粘贴下面的命令。下面的命令是在 ClickHouse Cloud 的 生产环境实例上执行的。
下面的步骤同样也适用于本地安装的 ClickHouse。唯一需要修改的是使用
s3 函数而不是 s3cluster (除非你已经配置了集群——在这种情况下，将 default 改为你的集群名称) 。分步指南
1
数据探索
让我们看看这些数据的样子。s3cluster 表函数会返回一个表，因此我们可以对结果执行 DESCRIBE：DESCRIBE s3(
'https://clickhouse-public-datasets.s3.amazonaws.com/youtube/original/files/*.zst',
'JSONLines'
);
┌─name────────────────┬─type───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┬─default_type─┬─default_expression─┬─comment─┬─codec_expression─┬─ttl_expression─┐
│ id │ Nullable(String) │ │ │ │ │ │
│ fetch_date │ Nullable(String) │ │ │ │ │ │
│ upload_date │ Nullable(String) │ │ │ │ │ │
│ title │ Nullable(String) │ │ │ │ │ │
│ uploader_id │ Nullable(String) │ │ │ │ │ │
│ uploader │ Nullable(String) │ │ │ │ │ │
│ uploader_sub_count │ Nullable(Int64) │ │ │ │ │ │
│ is_age_limit │ Nullable(Bool) │ │ │ │ │ │
│ view_count │ Nullable(Int64) │ │ │ │ │ │
│ like_count │ Nullable(Int64) │ │ │ │ │ │
│ dislike_count │ Nullable(Int64) │ │ │ │ │ │
│ is_crawlable │ Nullable(Bool) │ │ │ │ │ │
│ is_live_content │ Nullable(Bool) │ │ │ │ │ │
│ has_subtitles │ Nullable(Bool) │ │ │ │ │ │
│ is_ads_enabled │ Nullable(Bool) │ │ │ │ │ │
│ is_comments_enabled │ Nullable(Bool) │ │ │ │ │ │
│ description │ Nullable(String) │ │ │ │ │ │
│ rich_metadata │ Array(Tuple(call Nullable(String), content Nullable(String), subtitle Nullable(String), title Nullable(String), url Nullable(String))) │ │ │ │ │ │
│ super_titles │ Array(Tuple(text Nullable(String), url Nullable(String))) │ │ │ │ │ │
│ uploader_badges │ Nullable(String) │ │ │ │ │ │
│ video_badges │ Nullable(String) │ │ │ │ │ │
└─────────────────────┴────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┴──────────────┴────────────────────┴─────────┴──────────────────┴────────────────┘
2
创建表
根据推断出的 schema，我们对数据类型进行了整理，并添加了主键。 定义如下表：CREATE TABLE youtube
(
`id` String,
`fetch_date` DateTime,
`upload_date_str` String,
`upload_date` Date,
`title` String,
`uploader_id` String,
`uploader` String,
`uploader_sub_count` Int64,
`is_age_limit` Bool,
`view_count` Int64,
`like_count` Int64,
`dislike_count` Int64,
`is_crawlable` Bool,
`has_subtitles` Bool,
`is_ads_enabled` Bool,
`is_comments_enabled` Bool,
`description` String,
`rich_metadata` Array(Tuple(call String, content String, subtitle String, title String, url String)),
`super_titles` Array(Tuple(text String, url String)),
`uploader_badges` String,
`video_badges` String
)
ENGINE = MergeTree
ORDER BY (uploader, upload_date)
3
插入数据
以下命令会将 S3 文件中的记录流式写入youtube 表。这会插入大量数据——46.5 亿行。如果你不需要整个数据集，只需添加一个
LIMIT 子句，并指定所需的行数。INSERT INTO youtube
SETTINGS input_format_null_as_default = 1
SELECT
id,
parseDateTimeBestEffortUSOrZero(toString(fetch_date)) AS fetch_date,
upload_date AS upload_date_str,
toDate(parseDateTimeBestEffortUSOrZero(upload_date::String)) AS upload_date,
ifNull(title, '') AS title,
uploader_id,
ifNull(uploader, '') AS uploader,
uploader_sub_count,
is_age_limit,
view_count,
like_count,
dislike_count,
is_crawlable,
has_subtitles,
is_ads_enabled,
is_comments_enabled,
ifNull(description, '') AS description,
rich_metadata,
super_titles,
ifNull(uploader_badges, '') AS uploader_badges,
ifNull(video_badges, '') AS video_badges
FROM s3(
'https://clickhouse-public-datasets.s3.amazonaws.com/youtube/original/files/*.zst',
'JSONLines'
)
INSERT 命令，有几点说明：- 当传入的日期字段格式可能不正确时，
parseDateTimeBestEffortUSOrZero函数会很有用。如果fetch_date无法被正确解析，就会被设为0 upload_date列中既有有效日期，也有像 “4 hours ago” 这样的字符串——这显然不是有效日期。我们决定将原始值存储在upload_date_str中，并尝试用toDate(parseDateTimeBestEffortUSOrZero(upload_date::String))对其进行解析。如果解析失败，结果就会是0- 我们使用
ifNull来避免表中出现NULL值。如果传入的值是NULL，ifNull函数会将其设为空字符串
4
统计行数
在 ClickHouse Cloud 的 SQL 控制台中打开一个新标签页 (或新开一个clickhouse-client 窗口) ，观察计数持续增加。
插入 45.6 亿行需要一些时间，具体取决于服务器资源。 (如果不调整任何设置，大约需要 4.5 小时。)SELECT formatReadableQuantity(count())
FROM youtube
┌─formatReadableQuantity(count())─┐
│ 4.56 billion │
└─────────────────────────────────┘
5
探索数据
数据插入后，不妨统计一下你喜欢的视频或频道被点踩的次数。让我们看看 ClickHouse 上传了多少个视频：SELECT count()
FROM youtube
WHERE uploader = 'ClickHouse';
┌─count()─┐
│ 84 │
└─────────┘
1 row in set. Elapsed: 0.570 sec. Processed 237.57 thousand rows, 5.77 MB (416.54 thousand rows/s., 10.12 MB/s.)
上面的查询之所以运行得这么快，是因为我们将
uploader 选作主键的第一列，因此只需处理 23.7 万行。SELECT
title,
like_count,
dislike_count
FROM youtube
WHERE uploader = 'ClickHouse'
ORDER BY dislike_count DESC;
┌─title────────────────────────────────────────────────────────────────────────────────────────────────┬─like_count─┬─dislike_count─┐
│ ClickHouse v21.11 Release Webinar │ 52 │ 3 │
│ ClickHouse Introduction │ 97 │ 3 │
│ Casa Modelo Algarve │ 180 │ 3 │
│ Профайлер запросов: трудный путь │ 33 │ 3 │
│ ClickHouse в Курсометре │ 4 │ 2 │
│ 10 Good Reasons to Use ClickHouse │ 27 │ 2 │
...
84 rows in set. Elapsed: 0.013 sec. Processed 155.65 thousand rows, 16.94 MB (11.96 million rows/s., 1.30 GB/s.)
title 或 description 字段中包含 ClickHouse 的视频进行的搜索：SELECT
view_count,
like_count,
dislike_count,
concat('https://youtu.be/', id) AS url,
title
FROM youtube
WHERE (title ILIKE '%ClickHouse%') OR (description ILIKE '%ClickHouse%')
ORDER BY
like_count DESC,
view_count DESC;
1174 rows in set. Elapsed: 1099.368 sec. Processed 4.56 billion rows, 1.98 TB (4.15 million rows/s., 1.80 GB/s.)
┌─view_count─┬─like_count─┬─dislike_count─┬─url──────────────────────────┬─title──────────────────────────────────────────────────────────────────────────────────────────────────┐
│ 1919 │ 63 │ 1 │ https://youtu.be/b9MeoOtAivQ │ ClickHouse v21.10 Release Webinar │
│ 8710 │ 62 │ 4 │ https://youtu.be/PeV1mC2z--M │ What is JDBC DriverManager? | JDBC │
│ 3534 │ 62 │ 1 │ https://youtu.be/8nWRhK9gw10 │ CLICKHOUSE - Arquitetura Modular │
常见问题
如果有人关闭评论功能，是否会降低人们实际去点“点赞”或“点踩”的可能性？
SELECT
concat('< ', formatReadableQuantity(view_range)) AS views,
is_comments_enabled,
total_clicks / num_views AS prob_like_dislike
FROM
(
SELECT
is_comments_enabled,
power(10, CEILING(log10(view_count + 1))) AS view_range,
sum(like_count + dislike_count) AS total_clicks,
sum(view_count) AS num_views
FROM youtube
GROUP BY
view_range,
is_comments_enabled
) WHERE view_range > 1
ORDER BY
is_comments_enabled ASC,
num_views ASC;
┌─views─────────────┬─is_comments_enabled─┬────prob_like_dislike─┐
│ < 10.00 │ false │ 0.08224180712685371 │
│ < 100.00 │ false │ 0.06346337759167248 │
│ < 1.00 thousand │ false │ 0.03201883652987105 │
│ < 10.00 thousand │ false │ 0.01716073540410903 │
│ < 10.00 billion │ false │ 0.004555639481829971 │
│ < 100.00 thousand │ false │ 0.01293351460515323 │
│ < 1.00 billion │ false │ 0.004761811192464957 │
│ < 1.00 million │ false │ 0.010472604018980551 │
│ < 10.00 million │ false │ 0.00788902538420125 │
│ < 100.00 million │ false │ 0.00579152804250582 │
│ < 10.00 │ true │ 0.09819517478134059 │
│ < 100.00 │ true │ 0.07403784478585775 │
│ < 1.00 thousand │ true │ 0.03846294910067627 │
│ < 10.00 billion │ true │ 0.005615217329358215 │
│ < 10.00 thousand │ true │ 0.02505881391701455 │
│ < 1.00 billion │ true │ 0.007434998802482997 │
│ < 100.00 thousand │ true │ 0.022694648130822004 │
│ < 100.00 million │ true │ 0.011761563746575625 │
│ < 1.00 million │ true │ 0.020776022304589435 │
│ < 10.00 million │ true │ 0.016917095718089584 │
└───────────────────┴─────────────────────┴──────────────────────┘
22 rows in set. Elapsed: 8.460 sec. Processed 4.56 billion rows, 77.48 GB (538.73 million rows/s., 9.16 GB/s.)
视频数量随时间如何变化——有哪些值得注意的事件？
SELECT
toStartOfMonth(toDateTime(upload_date)) AS month,
uniq(uploader_id) AS uploaders,
count() AS num_videos,
sum(view_count) AS view_count
FROM youtube
GROUP BY month
ORDER BY month ASC;
┌──────month─┬─uploaders─┬─num_videos─┬───view_count─┐
│ 2005-04-01 │ 5 │ 6 │ 213597737 │
│ 2005-05-01 │ 6 │ 9 │ 2944005 │
│ 2005-06-01 │ 165 │ 351 │ 18624981 │
│ 2005-07-01 │ 395 │ 1168 │ 94164872 │
│ 2005-08-01 │ 1171 │ 3128 │ 124540774 │
│ 2005-09-01 │ 2418 │ 5206 │ 475536249 │
│ 2005-10-01 │ 6750 │ 13747 │ 737593613 │
│ 2005-11-01 │ 13706 │ 28078 │ 1896116976 │
│ 2005-12-01 │ 24756 │ 49885 │ 2478418930 │
│ 2006-01-01 │ 49992 │ 100447 │ 4532656581 │
│ 2006-02-01 │ 67882 │ 138485 │ 5677516317 │
│ 2006-03-01 │ 103358 │ 212237 │ 8430301366 │
│ 2006-04-01 │ 114615 │ 234174 │ 9980760440 │
│ 2006-05-01 │ 152682 │ 332076 │ 14129117212 │
│ 2006-06-01 │ 193962 │ 429538 │ 17014143263 │
│ 2006-07-01 │ 234401 │ 530311 │ 18721143410 │
│ 2006-08-01 │ 281280 │ 614128 │ 20473502342 │
│ 2006-09-01 │ 312434 │ 679906 │ 23158422265 │
│ 2006-10-01 │ 404873 │ 897590 │ 27357846117 │
字幕是从什么时候开始逐渐增多的
SELECT
toStartOfMonth(upload_date) AS month,
countIf(has_subtitles) / count() AS percent_subtitles,
percent_subtitles - any(percent_subtitles) OVER (
ORDER BY month ASC ROWS BETWEEN 1 PRECEDING AND 1 PRECEDING
) AS previous
FROM youtube
GROUP BY month
ORDER BY month ASC;
┌──────month─┬───percent_subtitles─┬────────────────previous─┐
│ 2015-01-01 │ 0.2652653881082824 │ 0.2652653881082824 │
│ 2015-02-01 │ 0.3147556050309162 │ 0.049490216922633834 │
│ 2015-03-01 │ 0.32460464492371877 │ 0.009849039892802558 │
│ 2015-04-01 │ 0.33471963051468445 │ 0.010114985590965686 │
│ 2015-05-01 │ 0.3168087575501062 │ -0.017910872964578273 │
│ 2015-06-01 │ 0.3162609788438222 │ -0.0005477787062839745 │
│ 2015-07-01 │ 0.31828767677518033 │ 0.0020266979313581235 │
│ 2015-08-01 │ 0.3045551564286859 │ -0.013732520346494415 │
│ 2015-09-01 │ 0.311221133995152 │ 0.006665977566466086 │
│ 2015-10-01 │ 0.30574870926812175 │ -0.005472424727030245 │
│ 2015-11-01 │ 0.31125409712077234 │ 0.0055053878526505895 │
│ 2015-12-01 │ 0.3190967954651779 │ 0.007842698344405541 │
│ 2016-01-01 │ 0.32636021432496176 │ 0.007263418859783877 │
主要上传者随时间变化
WITH uploaders AS
(
SELECT uploader
FROM youtube
GROUP BY uploader
ORDER BY sum(view_count) DESC
LIMIT 10
)
SELECT
month,
uploader,
sum(view_count) AS total_views,
avg(dislike_count / like_count) AS like_to_dislike_ratio
FROM youtube
WHERE uploader IN (uploaders)
GROUP BY
toStartOfMonth(upload_date) AS month,
uploader
ORDER BY
month ASC,
total_views DESC;
┌──────month─┬─uploader───────────────────┬─total_views─┬─like_to_dislike_ratio─┐
│ 1970-01-01 │ T-Series │ 10957099 │ 0.022784656361208206 │
│ 1970-01-01 │ Ryan's World │ 0 │ 0.003035559410234172 │
│ 1970-01-01 │ SET India │ 0 │ nan │
│ 2006-09-01 │ Cocomelon - Nursery Rhymes │ 256406497 │ 0.7005566715978622 │
│ 2007-06-01 │ Cocomelon - Nursery Rhymes │ 33641320 │ 0.7088650914344298 │
│ 2008-02-01 │ WWE │ 43733469 │ 0.07198856488734842 │
│ 2008-03-01 │ WWE │ 16514541 │ 0.1230603715431997 │
│ 2008-04-01 │ WWE │ 5907295 │ 0.2089399470159618 │
│ 2008-05-01 │ WWE │ 7779627 │ 0.09101676560436774 │
│ 2008-06-01 │ WWE │ 7018780 │ 0.0974184753155297 │
│ 2008-07-01 │ WWE │ 4686447 │ 0.1263845422065158 │
│ 2008-08-01 │ WWE │ 4514312 │ 0.08384574274791441 │
│ 2008-09-01 │ WWE │ 3717092 │ 0.07872802579349912 │
随着观看量增加，点赞率如何变化？
SELECT
concat('< ', formatReadableQuantity(view_range)) AS view_range,
is_comments_enabled,
round(like_ratio, 2) AS like_ratio
FROM
(
SELECT
power(10, CEILING(log10(view_count + 1))) AS view_range,
is_comments_enabled,
avg(like_count / dislike_count) AS like_ratio
FROM youtube WHERE dislike_count > 0
GROUP BY
view_range,
is_comments_enabled HAVING view_range > 1
ORDER BY
view_range ASC,
is_comments_enabled ASC
);
┌─view_range────────┬─is_comments_enabled─┬─like_ratio─┐
│ < 10.00 │ false │ 0.66 │
│ < 10.00 │ true │ 0.66 │
│ < 100.00 │ false │ 3 │
│ < 100.00 │ true │ 3.95 │
│ < 1.00 thousand │ false │ 8.45 │
│ < 1.00 thousand │ true │ 13.07 │
│ < 10.00 thousand │ false │ 18.57 │
│ < 10.00 thousand │ true │ 30.92 │
│ < 100.00 thousand │ false │ 23.55 │
│ < 100.00 thousand │ true │ 42.13 │
│ < 1.00 million │ false │ 19.23 │
│ < 1.00 million │ true │ 37.86 │
│ < 10.00 million │ false │ 12.13 │
│ < 10.00 million │ true │ 30.72 │
│ < 100.00 million │ false │ 6.67 │
│ < 100.00 million │ true │ 23.32 │
│ < 1.00 billion │ false │ 3.08 │
│ < 1.00 billion │ true │ 20.69 │
│ < 10.00 billion │ false │ 1.77 │
│ < 10.00 billion │ true │ 19.5 │
└───────────────────┴─────────────────────┴────────────┘
观看量是如何分布的？
SELECT
labels AS percentile,
round(quantiles) AS views
FROM
(
SELECT
quantiles(0.999, 0.99, 0.95, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1)(view_count) AS quantiles,
['99.9th', '99th', '95th', '90th', '80th', '70th','60th', '50th', '40th', '30th', '20th', '10th'] AS labels
FROM youtube
)
ARRAY JOIN
quantiles,
labels;
┌─percentile─┬───views─┐
│ 99.9th │ 1216624 │
│ 99th │ 143519 │
│ 95th │ 13542 │
│ 90th │ 4054 │
│ 80th │ 950 │
│ 70th │ 363 │
│ 60th │ 177 │
│ 50th │ 97 │
│ 40th │ 57 │
│ 30th │ 32 │
│ 20th │ 16 │
│ 10th │ 6 │
└────────────┴─────────┘