Apache Hudi 使用文件聚类功能 (Clustering) 解决小文件过多的问题
Apache Hudi 使用文件聚类功能 (Clustering) 解决小文件过多的问题
王知无-import_bigdata
发布于 2022-11-11 19:16:38
发布于 2022-11-11 19:16:38
Hudi测试：批处理后文件据类再接流
本文详细阐述了在 “批处理后，流处理之前” 进行文件 Clustering 操作的方法。该方法可以将众多小文件合并成数量极少的大文件，从而防止过多小文件的产生。
在批处理结束后进行 Clustering 主要涉及如下几个步骤，它们主要都是通过 spark-submit 命令完成的：
- 制定 Clustering 计划，找到
批处理数据结束
首先用 bulk_insert 方式运行批处理任务。注意下面的操作都是在批处理任务完成后，接流之前进行。
查看表相关的 hdfs，可以发现由于使用了 bulk_insert 的方式写入数据，导致文件数量非常多，而每个文件的 Size 非常小。我们希望将每个分区的1000多个小文件聚合成几个大文件，以免造成不必要的查询和系统维护开销。
[hadoop@p0-tklfrna-tklrna-device02 hudi_clustering]$ hdfs dfs -count /flk_hudi/chdrpf_hudi_test03/*
7 7 32637997 /flk_hudi/chdrpf_hudi_test03/.hoodie
1 1067 571117942 /flk_hudi/chdrpf_hudi_test03/1
1 1071 716513820 /flk_hudi/chdrpf_hudi_test03/2
1 1072 644997032 /flk_hudi/chdrpf_hudi_test03/3
1 1072 507397985 /flk_hudi/chdrpf_hudi_test03/4
1 1069 730774472 /flk_hudi/chdrpf_hudi_test03/5
1 1067 586561261 /flk_hudi/chdrpf_hudi_test03/6
1 1063 557377359 /flk_hudi/chdrpf_hudi_test03/7
1 1070 483416155 /flk_hudi/chdrpf_hudi_test03/8
1 1071 587965407 /flk_hudi/chdrpf_hudi_test03/A
1 1071 570651877 /flk_hudi/chdrpf_hudi_test03/B
1 1068 796163049 /flk_hudi/chdrpf_hudi_test03/C
1 1064 732633320 /flk_hudi/chdrpf_hudi_test03/D
1 1067 524777141 /flk_hudi/chdrpf_hudi_test03/E
1 1070 550302848 /flk_hudi/chdrpf_hudi_test03/F
1 1076 540059544 /flk_hudi/chdrpf_hudi_test03/G
1 1071 590094172 /flk_hudi/chdrpf_hudi_test03/H
1 1076 505755100 /flk_hudi/chdrpf_hudi_test03/I
1 1068 606771875 /flk_hudi/chdrpf_hudi_test03/J
1 1068 495261290 /flk_hudi/chdrpf_hudi_test03/K
1 1067 516964732 /flk_hudi/chdrpf_hudi_test03/L
1 1060 482056347 /flk_hudi/chdrpf_hudi_test03/M
1 1054 607625266 /flk_hudi/chdrpf_hudi_test03/N
1 1077 551989638 /flk_hudi/chdrpf_hudi_test03/O
1 1076 590537140 /flk_hudi/chdrpf_hudi_test03/P
1 1069 536362956 /flk_hudi/chdrpf_hudi_test03/Q
1 1072 559723804 /flk_hudi/chdrpf_hudi_test03/R
1 1067 546042696 /flk_hudi/chdrpf_hudi_test03/S
1 1059 528438508 /flk_hudi/chdrpf_hudi_test03/T
1 1063 518288413 /flk_hudi/chdrpf_hudi_test03/U
1 1070 543146873 /flk_hudi/chdrpf_hudi_test03/V
1 1066 532588113 /flk_hudi/chdrpf_hudi_test03/W
1 1069 494606809 /flk_hudi/chdrpf_hudi_test03/X
1 1079 527128056 /flk_hudi/chdrpf_hudi_test03/Y
1 1068 477378497 /flk_hudi/chdrpf_hudi_test03/Z
1 1075 471848267 /flk_hudi/chdrpf_hudi_test03/a
查看当前 hdfs 路径下的文件个数。可以发现由于 bulk_insert 导致小文件非常之多，这会显著影响查询的性能 (一次查询可能要做几千个 IO 操作)。
[hadoop@p0-tklfrna-tklrna-device02 hudi_clustering]$ hdfs dfs -count /flk_hudi/chdrpf_hudi_test03/
43 37452 22269590565 /flk_hudi/chdrpf_hudi_test03
Clustering
配置清理策略
使用最简配置方法如下
[hadoop@p0-tklfrna-tklrna-device02 hudi_clustering]$ cat /home/hadoop/hudi_clustering/clusteringjob.properties
hoodie.clustering.inline.max.commits=2
hoodie.clustering.plan.strategy.max.num.groups=40
添加高级配置项
[hadoop@p0-tklfrna-tklrna-device02 ~]$ cat /home/hadoop/hudi_clustering/clusteringjob.properties
hoodie.clustering.inline=true
hoodie.clustering.inline.max.commits=2
hoodie.clustering.plan.strategy.max.num.groups=40
hoodie.clustering.plan.strategy.target.file.max.bytes=1073741824
hoodie.clustering.plan.strategy.max.bytes.per.group=2147483648
hoodie.clustering.plan.strategy.small.file.limit=629145600
Schedule
指定 Clustering 计划。计划制定完毕后 Hudi 对应 hdfs 的 Timeline 中会出现相应时间戳，以供执行计划。
spark-submit \
--master yarn \
--class org.apache.hudi.utilities.HoodieClusteringJob \
hdfs://nameservice1/utility_jars/hudi-utilities-bundle_2.12-0.10.0.jar \
--schedule \
--base-path hdfs://nameservice1/flk_hudi/chdrpf_hudi_test03 \
--table-name chdrpf_hudi_test03 \
--props file:///home/hadoop/hudi_clustering/clusteringjob.properties \
--spark-memory 16g \
> /home/hadoop/hudi_clustering/clusteringjob.log 2>&1
查看 Hdfs 中的 Hudi 的 Timeline 获取时间戳。文件后缀为 replacecommit.requested 的时间戳即为我们需要的时间戳。复制我们需要的 20220826105913373，以便下一步粘贴。
[hadoop@p0-tklfrna-tklrna-device02 ~]$ hdfs dfs -ls /flk_hudi/chdrpf_hudi_test03/.hoodie/
Found 407 items
drwxr-xr-x - hadoop supergroup 0 2022-08-26 10:10 /flk_hudi/chdrpf_hudi_test03/.hoodie/.aux
drwxr-xr-x - hadoop supergroup 0 2022-08-26 14:53 /flk_hudi/chdrpf_hudi_test03/.hoodie/.temp
-rw-r--r-- 3 hadoop supergroup 18596070 2022-08-26 10:14 /flk_hudi/chdrpf_hudi_test03/.hoodie/20220826101036547.commit
-rw-r--r-- 3 hadoop supergroup 0 2022-08-26 10:10 /flk_hudi/chdrpf_hudi_test03/.hoodie/20220826101036547.commit.requested
-rw-r--r-- 3 hadoop supergroup 0 2022-08-26 10:10 /flk_hudi/chdrpf_hudi_test03/.hoodie/20220826101036547.inflight
-rw-r--r-- 3 hadoop supergroup 14041389 2022-08-26 10:16 /flk_hudi/chdrpf_hudi_test03/.hoodie/20220826101404432.commit
-rw-r--r-- 3 hadoop supergroup 0 2022-08-26 10:14 /flk_hudi/chdrpf_hudi_test03/.hoodie/20220826101404432.commit.requested
-rw-r--r-- 3 hadoop supergroup 0 2022-08-26 10:14 /flk_hudi/chdrpf_hudi_test03/.hoodie/20220826101404432.inflight
...
-rw-r--r-- 3 hadoop supergroup 5685565 2022-08-26 10:59 /flk_hudi/chdrpf_hudi_test03/.hoodie/20220826105913373.replacecommit.requested
...
Execute
Clustering 执行需要使用刚才的时间戳配置 --instant-time 20220826105913373 于命令中即可执行。
spark-submit \
--master yarn \
--class org.apache.hudi.utilities.HoodieClusteringJob \
hdfs://nameservice1/utility_jars/hudi-utilities-bundle_2.12-0.10.0.jar \
--instant-time 20220826105913373 \
--base-path hdfs://nameservice1/flk_hudi/chdrpf_hudi_test03 \
--table-name chdrpf_hudi_test03 \
--props file:///home/hadoop/hudi_clustering/clusteringjob.properties \
--spark-memory 16g \
> /home/hadoop/hudi_clustering/clusteringjob_execution.log 2>&1
文件聚类完毕后
[hadoop@p0-tklfrna-tklrna-device02 hudi_clustering]$ hdfs dfs -count /flk_hudi/chdrpf_hudi_test03/*
7 10 39759457 /flk_hudi/chdrpf_hudi_test03/.hoodie
1 1068 644693330 /flk_hudi/chdrpf_hudi_test03/1
1 1072 912384991 /flk_hudi/chdrpf_hudi_test03/2
1 1073 783040567 /flk_hudi/chdrpf_hudi_test03/3
1 1073 535431665 /flk_hudi/chdrpf_hudi_test03/4
1 1070 938545286 /flk_hudi/chdrpf_hudi_test03/5
1 1068 676230669 /flk_hudi/chdrpf_hudi_test03/6
1 1064 625387487 /flk_hudi/chdrpf_hudi_test03/7
1 1071 494572949 /flk_hudi/chdrpf_hudi_test03/8
1 1072 675599389 /flk_hudi/chdrpf_hudi_test03/A
1 1072 643710911 /flk_hudi/chdrpf_hudi_test03/B
1 1069 1056860522 /flk_hudi/chdrpf_hudi_test03/C
1 1065 940690081 /flk_hudi/chdrpf_hudi_test03/D
1 1068 563929957 /flk_hudi/chdrpf_hudi_test03/E
1 1071 606406555 /flk_hudi/chdrpf_hudi_test03/F
1 1077 589463777 /flk_hudi/chdrpf_hudi_test03/G
1 1072 682564783 /flk_hudi/chdrpf_hudi_test03/H
1 1077 529816271 /flk_hudi/chdrpf_hudi_test03/I
1 1069 712917512 /flk_hudi/chdrpf_hudi_test03/J
1 1069 514668751 /flk_hudi/chdrpf_hudi_test03/K
1 1068 550874973 /flk_hudi/chdrpf_hudi_test03/L
1 1061 495250431 /flk_hudi/chdrpf_hudi_test03/M
1 1055 716887761 /flk_hudi/chdrpf_hudi_test03/N
1 1078 612144859 /flk_hudi/chdrpf_hudi_test03/O
1 1077 679350316 /flk_hudi/chdrpf_hudi_test03/P
1 1070 586176818 /flk_hudi/chdrpf_hudi_test03/Q
1 1073 625760986 /flk_hudi/chdrpf_hudi_test03/R
1 1068 603042997 /flk_hudi/chdrpf_hudi_test03/S
1 1060 576062292 /flk_hudi/chdrpf_hudi_test03/T
1 1064 555764103 /flk_hudi/chdrpf_hudi_test03/U
1 1071 598050377 /flk_hudi/chdrpf_hudi_test03/V
1 1066 532588113 /flk_hudi/chdrpf_hudi_test03/W
1 1069 494606809 /flk_hudi/chdrpf_hudi_test03/X
1 1079 527128056 /flk_hudi/chdrpf_hudi_test03/Y
1 1068 477378497 /flk_hudi/chdrpf_hudi_test03/Z
1 1075 471848267 /flk_hudi/chdrpf_hudi_test03/a
运行清理
在进行完 Clustering 操作后，很多小文件都被合并进大文件了。由于 Hudi 不会主动删除过期和不必要的文件，因此需要利用手动清理策略来对过期文件进行清理删除。
清理策略的配置文件
[hadoop@p0-tklfrna-tklrna-device02 hudi_clustering]$ cat /home/hadoop/hudi_clustering/hudi_cleaning.properties
# hudi_cleaning.properties
# When enabled, the cleaner table service is invoked immediately after each commit, to delete older file slices
hoodie.clean.automatic=true
# Only applies when hoodie.clean.automatic is turned on.
# When turned on runs cleaner async with writing, which can speed up overall write performance.
hoodie.clean.async=true
# # This policy has the effect of keeping N number of file versions irrespective of time.
# # This policy is useful when it is known how many MAX versions of the file does one want to keep at any given time.
# # hoodie.cleaner.policy=KEEP_LATEST_COMMITS
hoodie.cleaner.policy=KEEP_LATEST_COMMITS
# # Number of commits to retain, without cleaning.
# # This will be retained for num_of_commits * time_between_commits (scheduled).
# # hoodie.cleaner.commits.retained=3
# When KEEP_LATEST_FILE_VERSIONS cleaning policy is used,
# the minimum number of file slices to retain in each file group, during cleaning.
hoodie.cleaner.commits.retained=1
# When set to true, cleaner also deletes the bootstrap base file when it's skeleton base file is cleaned.
hoodie.cleaner.delete.bootstrap.base.file=false
# Only if the log file size is greater than the threshold in bytes, the file group will be compacted.
hoodie.commits.archival.batch=60
hoodie.archive.merge.small.file.limit.bytes=104857600
# When set to true, compaction service is triggered after each write.
# While being simpler operationally, this adds extra latency on the write path.
hoodie.compact.inline=false
hoodie.parquet.small.file.limit=124857600
hoodie.cleaner.parallelism=800
hoodie.cleaner.incremental.mode=true
# Archiving service moves older entries from timeline into an archived log after each write,
# to keep the metadata overhead constant, even as the table size grows
hoodie.keep.max.commits=3
hoodie.keep.min.commits=2
利用命令执行清理策略
spark-submit \
--class org.apache.hudi.utilities.HoodieCleaner \
hdfs://nameservice1/utility_jars/hudi-utilities-bundle_2.12-0.10.0.jar \
--props file:///home/hadoop/hudi_clustering/hudi_cleaning.properties \
--target-base-path hdfs://nameservice1/flk_hudi/chdrpf_hudi_test03 \
> /home/hadoop/hudi_clustering/clusteringjob_cleaning.log 2>&1
接流处理任务
此时，可以将流处理任务接至该 Hudi 表中。文件清理的效果会在 Hudi 接流后显现。
清理后文件个数
[hadoop@p0-tklfrna-tklrna-device02 hudi_clustering]$ hdfs dfs -count /flk_hudi/chdrpf_hudi_test03/* 39 2818 61047630 /flk_hudi/chdrpf_hudi_test03/.hoodie
1 5 295730057 /flk_hudi/chdrpf_hudi_test03/1
1 5 581449403 /flk_hudi/chdrpf_hudi_test03/2
1 5 541564433 /flk_hudi/chdrpf_hudi_test03/3
1 5 113526185 /flk_hudi/chdrpf_hudi_test03/4
1 5 819123981 /flk_hudi/chdrpf_hudi_test03/5
1 5 361258893 /flk_hudi/chdrpf_hudi_test03/6
1 4 205559110 /flk_hudi/chdrpf_hudi_test03/7
1 4 33721101 /flk_hudi/chdrpf_hudi_test03/8
1 5 352884732 /flk_hudi/chdrpf_hudi_test03/A
1 5 294248033 /flk_hudi/chdrpf_hudi_test03/B
1 5 771533591 /flk_hudi/chdrpf_hudi_test03/C
1 5 614827884 /flk_hudi/chdrpf_hudi_test03/D
1 5 157676833 /flk_hudi/chdrpf_hudi_test03/E
1 5 226004511 /flk_hudi/chdrpf_hudi_test03/F
1 5 198656601 /flk_hudi/chdrpf_hudi_test03/G
1 5 372307018 /flk_hudi/chdrpf_hudi_test03/H
1 5 97041611 /flk_hudi/chdrpf_hudi_test03/I
1 5 427390894 /flk_hudi/chdrpf_hudi_test03/J
1 5 78296341 /flk_hudi/chdrpf_hudi_test03/K
1 5 136428423 /flk_hudi/chdrpf_hudi_test03/L
1 5 53218521 /flk_hudi/chdrpf_hudi_test03/M
1 5 439899957 /flk_hudi/chdrpf_hudi_test03/N
1 5 242278011 /flk_hudi/chdrpf_hudi_test03/O
1 5 357549763 /flk_hudi/chdrpf_hudi_test03/P
1 5 200702230 /flk_hudi/chdrpf_hudi_test03/Q
1 5 265952714 /flk_hudi/chdrpf_hudi_test03/R
1 5 229783530 /flk_hudi/chdrpf_hudi_test03/S
1 5 191817537 /flk_hudi/chdrpf_hudi_test03/T
1 5 151138760 /flk_hudi/chdrpf_hudi_test03/U
1 5 221236895 /flk_hudi/chdrpf_hudi_test03/V
1 4112 2060894265 /flk_hudi/chdrpf_hudi_test03/W
1 4117 1910706738 /flk_hudi/chdrpf_hudi_test03/X
1 4169 2042792364 /flk_hudi/chdrpf_hudi_test03/Y
1 2221 995253322 /flk_hudi/chdrpf_hudi_test03/Z
1 1075 472877437 /flk_hudi/chdrpf_hudi_test03/a
可以看到每个分区内的小文件已经被聚合成大文件，并随着流数据的进入，文件数量的增长速度也在合理范围内。
Ps: 我们把后几个分区作为对照组没有进行文件聚合。可以通过在 Clustering 的配置文件中调大 hoodie.clustering.plan.strategy.max.num.groups=30 的值来增加 SparkJob 的 parallelism 从而把所有分区涵盖进行，进行文件聚合。
[hadoop@p0-tklfrna-tklrna-device02 hudi_clustering]$ hdfs dfs -count /flk_hudi/chdrpf_hudi_test03/
76 19050 17396389394 /flk_hudi/chdrpf_hudi_test03
Timeline 观察
20220826105913373.replacecommit表示进行完毕聚类操作的时刻
20220826114108591.clean表示进行完毕清理操作的时刻
20220826114317026.commit表示进行完毕新数据写入操作的时刻
[hadoop@p0-tklfrna-tklrna-device02 hudi_clustering]$ hdfs dfs -ls /flk_hudi/chdrpf_hudi_test03/.hoodie
Found 30 items
drwxr-xr-x - hadoop supergroup 0 2022-08-26 10:10 /flk_hudi/chdrpf_hudi_test03/.hoodie/.aux
drwxr-xr-x - hadoop supergroup 0 2022-08-26 11:46 /flk_hudi/chdrpf_hudi_test03/.hoodie/.temp
-rw-r--r-- 3 hadoop supergroup 18596070 2022-08-26 10:14 /flk_hudi/chdrpf_hudi_test03/.hoodie/20220826101036547.commit
-rw-r--r-- 3 hadoop supergroup 0 2022-08-26 10:10 /flk_hudi/chdrpf_hudi_test03/.hoodie/20220826101036547.commit.requested
-rw-r--r-- 3 hadoop supergroup 0 2022-08-26 10:10 /flk_hudi/chdrpf_hudi_test03/.hoodie/20220826101036547.inflight
-rw-r--r-- 3 hadoop supergroup 14041389 2022-08-26 10:16 /flk_hudi/chdrpf_hudi_test03/.hoodie/20220826101404432.commit
-rw-r--r-- 3 hadoop supergroup 0 2022-08-26 10:14 /flk_hudi/chdrpf_hudi_test03/.hoodie/20220826101404432.commit.requested
-rw-r--r-- 3 hadoop supergroup 0 2022-08-26 10:14 /flk_hudi/chdrpf_hudi_test03/.hoodie/20220826101404432.inflight
-rw-r--r-- 3 hadoop supergroup 1435895 2022-08-26 11:09 /flk_hudi/chdrpf_hudi_test03/.hoodie/20220826105913373.replacecommit
-rw-r--r-- 3 hadoop supergroup 0 2022-08-26 11:03 /flk_hudi/chdrpf_hudi_test03/.hoodie/20220826105913373.replacecommit.inflight
-rw-r--r-- 3 hadoop supergroup 5685565 2022-08-26 10:59 /flk_hudi/chdrpf_hudi_test03/.hoodie/20220826105913373.replacecommit.requested
-rw-r--r-- 3 hadoop supergroup 1009885 2022-08-26 11:37 /flk_hudi/chdrpf_hudi_test03/.hoodie/20220826113342082.commit
-rw-r--r-- 3 hadoop supergroup 0 2022-08-26 11:33 /flk_hudi/chdrpf_hudi_test03/.hoodie/20220826113342082.commit.requested
-rw-r--r-- 3 hadoop supergroup 0 2022-08-26 11:33 /flk_hudi/chdrpf_hudi_test03/.hoodie/20220826113342082.inflight
-rw-r--r-- 3 hadoop supergroup 3811303 2022-08-26 11:40 /flk_hudi/chdrpf_hudi_test03/.hoodie/20220826113740364.commit
-rw-r--r-- 3 hadoop supergroup 0 2022-08-26 11:37 /flk_hudi/chdrpf_hudi_test03/.hoodie/20220826113740364.commit.requested
-rw-r--r-- 3 hadoop supergroup 0 2022-08-26 11:37 /flk_hudi/chdrpf_hudi_test03/.hoodie/20220826113740364.inflight
-rw-r--r-- 3 hadoop supergroup 2940587 2022-08-26 11:43 /flk_hudi/chdrpf_hudi_test03/.hoodie/20220826114026452.commit
-rw-r--r-- 3 hadoop supergroup 0 2022-08-26 11:40 /flk_hudi/chdrpf_hudi_test03/.hoodie/20220826114026452.commit.requested
-rw-r--r-- 3 hadoop supergroup 0 2022-08-26 11:40 /flk_hudi/chdrpf_hudi_test03/.hoodie/20220826114026452.inflight
-rw-r--r-- 3 hadoop supergroup 5005100 2022-08-26 11:41 /flk_hudi/chdrpf_hudi_test03/.hoodie/20220826114108591.clean
-rw-r--r-- 3 hadoop supergroup 4260649 2022-08-26 11:41 /flk_hudi/chdrpf_hudi_test03/.hoodie/20220826114108591.clean.inflight
-rw-r--r-- 3 hadoop supergroup 4260649 2022-08-26 11:41 /flk_hudi/chdrpf_hudi_test03/.hoodie/20220826114108591.clean.requested
-rw-r--r-- 3 hadoop supergroup 2867542 2022-08-26 11:46 /flk_hudi/chdrpf_hudi_test03/.hoodie/20220826114317026.commit
-rw-r--r-- 3 hadoop supergroup 0 2022-08-26 11:43 /flk_hudi/chdrpf_hudi_test03/.hoodie/20220826114317026.commit.requested如果这个文章对你有帮助，不要忘记 「在看」 「点赞」 「收藏」 三连啊喂！
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原始发表：2022-10-13，如有侵权请联系 cloudcommunity@tencent.com 删除
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