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我在 lxc 容器上运行 Percona 5.6 集群（3 个节点）。各节点硬件如下：

4 x Intel(R) Xeon(R) CPU E5-2630 v3 @ 2.40GHz (2 Sockets)
16GB RAM
130GB HD

我的数据库大小不到 4GB。我设法调整了配置设置，以便快速处理选择。但是，我看到一些 UPDATE 和 INSERT 执行速度很慢（5 秒以上）。所以一定有某种瓶颈，我想知道我是否可以通过配置调整来解决。

我知道有几个表可能需要删除一些未使用的索引，但我想知道还有什么可以提高查询的性能。负载并没有那么大，大约有 100 个用户，因为它是一个内部系统。

innodb_buffer_pool_size: 8G
innodb_log_file_size: 256M
innodb_log_buffer_size: 128M
innodb_flush_log_at_trx_commit: 2
innodb_thread_concurrency: 0
innodb_flush_method: O_DIRECT
innodb_file_per_table: ON

这是我的 SHOW ENGINE INNODB 状态：

| InnoDB |      | 
=====================================
2018-08-14 15:22:02 7f3330863700 INNODB MONITOR OUTPUT
=====================================
Per second averages calculated from the last 9 seconds
-----------------
BACKGROUND THREAD
-----------------
srv_master_thread loops: 22626 srv_active, 0 srv_shutdown, 79338 srv_idle
srv_master_thread log flush and writes: 101963
----------
SEMAPHORES
----------
OS WAIT ARRAY INFO: reservation count 86267
OS WAIT ARRAY INFO: signal count 1537634
Mutex spin waits 800672, rounds 1115180, OS waits 19238
RW-shared spins 605666, rounds 2660513, OS waits 58073
RW-excl spins 79517, rounds 2104544, OS waits 8150
Spin rounds per wait: 1.39 mutex, 4.39 RW-shared, 26.47 RW-excl
------------
TRANSACTIONS
------------
Trx id counter 1057692300
Purge done for trx's n:o < 1057692300 undo n:o < 0 state: running but idle
History list length 2030
LIST OF TRANSACTIONS FOR EACH SESSION:
---TRANSACTION 0, not started
MySQL thread id 621427, OS thread handle 0x7f3330863700, query id 7014924 localhost myuser init
SHOW ENGINE INNODB STATUS
---TRANSACTION 0, not started
MySQL thread id 608823, OS thread handle 0x7f33311c8700, query id 6968932 10.0.10.200 myuser
---TRANSACTION 1057692298, not started
MySQL thread id 2, OS thread handle 0x7f35905c8700, query id 7014913 committed 7569847
--------
FILE I/O
--------
I/O thread 0 state: waiting for completed aio requests (insert buffer thread)
I/O thread 1 state: waiting for completed aio requests (log thread)
I/O thread 2 state: waiting for completed aio requests (read thread)
I/O thread 3 state: waiting for completed aio requests (read thread)
I/O thread 4 state: waiting for completed aio requests (read thread)
I/O thread 5 state: waiting for completed aio requests (read thread)
I/O thread 6 state: waiting for completed aio requests (write thread)
I/O thread 7 state: waiting for completed aio requests (write thread)
I/O thread 8 state: waiting for completed aio requests (write thread)
I/O thread 9 state: waiting for completed aio requests (write thread)
Pending normal aio reads: 0 [0, 0, 0, 0] , aio writes: 0 [0, 0, 0, 0] ,
 ibuf aio reads: 0, log i/o's: 0, sync i/o's: 0
Pending flushes (fsync) log: 0; buffer pool: 0
189853 OS file reads, 666579 OS file writes, 119023 OS fsyncs
0.00 reads/s, 0 avg bytes/read, 14.78 writes/s, 2.89 fsyncs/s
-------------------------------------
INSERT BUFFER AND ADAPTIVE HASH INDEX
-------------------------------------
Ibuf: size 1, free list len 926, seg size 928, 3164 merges
merged operations:
 insert 3331, delete mark 1275, delete 655
discarded operations:
 insert 0, delete mark 0, delete 0
9.67 hash searches/s, 95.66 non-hash searches/s
---
LOG
---
Log sequence number 75281381079
Log flushed up to   75281381079
Pages flushed up to 75281381079
Last checkpoint at  75281381079
Max checkpoint age    434154333
Checkpoint age target 420587011
Modified age          0
Checkpoint age        0
0 pending log writes, 0 pending chkp writes
142005 log i/o's done, 2.00 log i/o's/second
----------------------
BUFFER POOL AND MEMORY
----------------------
Total memory allocated 8942256128; in additional pool allocated 0
Total memory allocated by read views 776
Internal hash tables (constant factor + variable factor)
    Adaptive hash index 411468128   (151384312 + 260083816)
    Page hash           1107208 (buffer pool 0 only)
    Dictionary cache    39612436    (35402768 + 4209668)
    File system         1602712     (812272 + 790440)
    Lock system         21251648    (21250568 + 1080)
    Recovery system     0   (0 + 0)
Dictionary memory allocated 4209668
Buffer pool size        524280
Buffer pool size, bytes 8589803520
Free buffers            82805
Database pages          425581
Old database pages      157253
Modified db pages       0
Pending reads 0
Pending writes: LRU 0, flush list 0, single page 0
Pages made young 223, not young 0
0.00 youngs/s, 0.00 non-youngs/s
Pages read 189492, created 236089, written 496948
0.00 reads/s, 0.00 creates/s, 12.55 writes/s
Buffer pool hit rate 1000 / 1000, young-making rate 0 / 1000 not 0 / 1000
Pages read ahead 0.00/s, evicted without access 0.00/s, Random read ahead 0.00/s
LRU len: 425581, unzip_LRU len: 38
I/O sum[0]:cur[0], unzip sum[0]:cur[0]
----------------------
INDIVIDUAL BUFFER POOL INFO
----------------------
---BUFFER POOL 0
Buffer pool size        65535
Buffer pool size, bytes 1073725440
Free buffers            9846
Database pages          53705
Old database pages      19844
Modified db pages       0
Pending reads 0
Pending writes: LRU 0, flush list 0, single page 0
Pages made young 27, not young 0
0.00 youngs/s, 0.00 non-youngs/s
Pages read 24150, created 29555, written 83723
0.00 reads/s, 0.00 creates/s, 3.56 writes/s
Buffer pool hit rate 1000 / 1000, young-making rate 0 / 1000 not 0 / 1000
Pages read ahead 0.00/s, evicted without access 0.00/s, Random read ahead 0.00/s
LRU len: 53705, unzip_LRU len: 0
I/O sum[0]:cur[0], unzip sum[0]:cur[0]
---BUFFER POOL 1
Buffer pool size        65535
Buffer pool size, bytes 1073725440
Free buffers            9114
Database pages          54443
Old database pages      20117
Modified db pages       0
Pending reads 0
Pending writes: LRU 0, flush list 0, single page 0
Pages made young 28, not young 0
0.00 youngs/s, 0.00 non-youngs/s
Pages read 24455, created 29988, written 46033
0.00 reads/s, 0.00 creates/s, 0.67 writes/s
Buffer pool hit rate 1000 / 1000, young-making rate 0 / 1000 not 0 / 1000
Pages read ahead 0.00/s, evicted without access 0.00/s, Random read ahead 0.00/s
LRU len: 54443, unzip_LRU len: 0
I/O sum[0]:cur[0], unzip sum[0]:cur[0]
---BUFFER POOL 2
Buffer pool size        65535
Buffer pool size, bytes 1073725440
Free buffers            10545
Database pages          53012
Old database pages      19588
Modified db pages       0
Pending reads 0
Pending writes: LRU 0, flush list 0, single page 0
Pages made young 27, not young 0
0.00 youngs/s, 0.00 non-youngs/s
Pages read 23505, created 29507, written 64763
0.00 reads/s, 0.00 creates/s, 1.89 writes/s
Buffer pool hit rate 1000 / 1000, young-making rate 0 / 1000 not 0 / 1000
Pages read ahead 0.00/s, evicted without access 0.00/s, Random read ahead 0.00/s
LRU len: 53012, unzip_LRU len: 0
I/O sum[0]:cur[0], unzip sum[0]:cur[0]
---BUFFER POOL 3
Buffer pool size        65535
Buffer pool size, bytes 1073725440
Free buffers            9551
Database pages          53984
Old database pages      19947
Modified db pages       0
Pending reads 0
Pending writes: LRU 0, flush list 0, single page 0
Pages made young 16, not young 0
0.00 youngs/s, 0.00 non-youngs/s
Pages read 24437, created 29547, written 61138
0.00 reads/s, 0.00 creates/s, 0.89 writes/s
Buffer pool hit rate 1000 / 1000, young-making rate 0 / 1000 not 0 / 1000
Pages read ahead 0.00/s, evicted without access 0.00/s, Random read ahead 0.00/s
LRU len: 53984, unzip_LRU len: 5
I/O sum[0]:cur[0], unzip sum[0]:cur[0]
---BUFFER POOL 4
Buffer pool size        65535
Buffer pool size, bytes 1073725440
Free buffers            10559
Database pages          52987
Old database pages      19579
Modified db pages       0
Pending reads 0
Pending writes: LRU 0, flush list 0, single page 0
Pages made young 29, not young 0
0.00 youngs/s, 0.00 non-youngs/s
Pages read 23524, created 29463, written 69996
0.00 reads/s, 0.00 creates/s, 2.11 writes/s
Buffer pool hit rate 1000 / 1000, young-making rate 0 / 1000 not 0 / 1000
Pages read ahead 0.00/s, evicted without access 0.00/s, Random read ahead 0.00/s
LRU len: 52987, unzip_LRU len: 0
I/O sum[0]:cur[0], unzip sum[0]:cur[0]
---BUFFER POOL 5
Buffer pool size        65535
Buffer pool size, bytes 1073725440
Free buffers            10906
Database pages          52633
Old database pages      19448
Modified db pages       0
Pending reads 0
Pending writes: LRU 0, flush list 0, single page 0
Pages made young 33, not young 0
0.00 youngs/s, 0.00 non-youngs/s
Pages read 23070, created 29563, written 60299
0.00 reads/s, 0.00 creates/s, 1.56 writes/s
Buffer pool hit rate 1000 / 1000, young-making rate 0 / 1000 not 0 / 1000
Pages read ahead 0.00/s, evicted without access 0.00/s, Random read ahead 0.00/s
LRU len: 52633, unzip_LRU len: 33
I/O sum[0]:cur[0], unzip sum[0]:cur[0]
---BUFFER POOL 6
Buffer pool size        65535
Buffer pool size, bytes 1073725440
Free buffers            10544
Database pages          53001
Old database pages      19583
Modified db pages       0
Pending reads 0
Pending writes: LRU 0, flush list 0, single page 0
Pages made young 20, not young 0
0.00 youngs/s, 0.00 non-youngs/s
Pages read 23685, created 29316, written 52866
0.00 reads/s, 0.00 creates/s, 0.78 writes/s
Buffer pool hit rate 1000 / 1000, young-making rate 0 / 1000 not 0 / 1000
Pages read ahead 0.00/s, evicted without access 0.00/s, Random read ahead 0.00/s
LRU len: 53001, unzip_LRU len: 0
I/O sum[0]:cur[0], unzip sum[0]:cur[0]
---BUFFER POOL 7
Buffer pool size        65535
Buffer pool size, bytes 1073725440
Free buffers            11740
Database pages          51816
Old database pages      19147
Modified db pages       0
Pending reads 0
Pending writes: LRU 0, flush list 0, single page 0
Pages made young 43, not young 0
0.00 youngs/s, 0.00 non-youngs/s
Pages read 22666, created 29150, written 58130
0.00 reads/s, 0.00 creates/s, 1.11 writes/s
Buffer pool hit rate 1000 / 1000, young-making rate 0 / 1000 not 0 / 1000
Pages read ahead 0.00/s, evicted without access 0.00/s, Random read ahead 0.00/s
LRU len: 51816, unzip_LRU len: 0
I/O sum[0]:cur[0], unzip sum[0]:cur[0]
--------------
ROW OPERATIONS
--------------
0 queries inside InnoDB, 0 queries in queue
0 read views open inside InnoDB
0 RW transactions active inside InnoDB
0 RO transactions active inside InnoDB
0 out of 1000 descriptors used
Main thread process no. 74272, id 139857921410816, state: sleeping
Number of rows inserted 12277268, updated 41111, deleted 326, read 31539377489
0.11 inserts/s, 0.67 updates/s, 0.00 deletes/s, 27069.99 reads/s
----------------------------
END OF INNODB MONITOR OUTPUT

更新 1

以下是有关最常出现问题的表的一些详细信息：

Engine: Innodb
Row format: Compact
Column Count: 124
Table Row: 581705 (I know, not alot!)
AVG row length: 560
Data lenght: 310.9MB
Index lenght: 411.4MB
Max data length: 0.0bytes
Data free: 4.0mb
Table size (estimate): 722.3MB
file format: antelope
Auto Increment: 745745
Table collation: utf8_unicode_ci

Number of Indices: 34 (most are BTREE, single column, non-unique Indices)

我认为这张表的最大问题是 1）indecies 的数量和 2）使用的数据类型。'bigint(20) unsigned' 有很多用法，我不能想象这完全没有必要。以及“mediumtext”字段。

我怀疑插入速度很慢，因为更新速度很慢。我怀疑这与使用的索引数量和大数据类型有关。

但是，我有大量可用的 CPU/Ram 可以在需要时投入使用，并且想知道是否有任何我可能想要查看的进一步配置。

更新 2

自上次重新启动 mysql ( https://www.percona.com/blog/2012/06/30/find-unused-indexes/ ) 以来，我已经启用了 userstat 来确定一些未使用的索引。事实证明，我只使用了 34 个索引中的 15 个。

更新 3

这是线程备份期间的状态输出：

https://pastebin.com/QhkHGH5s

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1 回答 1

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首先，如果您还没有监控，没有收集相同的数据，或者只是像它的外观一样，您可能会从使用PMM获得更好的实时洞察力中受益。您可以比较服务器并查找潜在问题，例如饱和 I/O、提交堆积等。有一个现场演示版本可以为您提供建议。

如果没有表结构和示例查询，就没有太多可做的事情，这将有助于排除查询本身而不是其他东西，但这里有一些观察结果：

  • 假设统计信息是最新的，那么您在索引中的数据比单独的数据还要多，这可能表明您需要清理索引并且必须做更多的工作来更新索引而不是必要的
  • 发布的表格显示了Antelope正在使用的旧格式，该格式已被该Barracuda格式取代；您提到mediumtext字段，通常将所有值存储在页外是最有效的，梭子鱼的动态行格式允许
  • 您已innodb_adaptive_hash_index启用，但这可能对您的工作量不利，因为您的未命中数看起来比命中数要高得多，但仍需要维护 AHI

还不清楚您是将写入发送到单个节点还是传播它们。Galera 不能帮助您扩展写入，因此如果您正在写入多个节点并看到冲突，那么切换到使用单个节点可能会有所帮助。

于 2018-08-15T17:12:00.923 回答