Mysql 5.5 InnoDB CPUの成長-夢中になる
おはようございます、
私は現在、サーバーがクラッシュするまでCPU使用率が上昇し続ける問題に直面しています。
このフォーラムとPerconaで提案された複数のベストプラクティスを試しましたが、サーバーをすでに2回再インストールしました。何も動作しないようです。
アプリケーションは、範囲インデックスでSELECT、主キーでUPDATE、UNIQUEキーで一括挿入を非常に集中的に実行する小さなスクリプトです。
クエリの99.9％が単一のInnoDBテーブルで実行されています。
Mysqltuner.plの出力は次のとおりです（まったく役に立ちませんでした）。
[--] Reads / Writes: 12% / 88% [--] Total buffers: 4.2G global + 5.0M per thread (100 max threads) [OK] Maximum possible memory usage: 4.7G (59% of installed RAM) [OK] Slow queries: 0% (1/1M) [OK] Highest usage of available connections: 42% (42/100) [OK] Key buffer size / total MyISAM indexes: 128.0M/29.3M [!!] Query cache is disabled [OK] Sorts requiring temporary tables: 0% (0 temp sorts / 2 sorts) [OK] Temporary tables created on disk: 19% (63 on disk / 327 total) [OK] Thread cache hit rate: 58% (42 created / 102 connections) [OK] Table cache hit rate: 38% (126 open / 325 opened) [OK] Open file limit used: 3% (68/2K) [OK] Table locks acquired immediately: 96% (1M immediate / 1M locks) [OK] InnoDB buffer pool / data size: 4.0G/358.1M [OK] InnoDB log waits: 0
My.cnfファイルは、私の知る限り、およびプロが使用またはアドバイスしているのを見たものに最適化されています。
# general tuning
# family of join_buffer_size ,sort_buffer_size, read_buffer_size, read_rnd_buffer_size
sort_buffer_size = 4M
read_rnd_buffer_size = 512K
table_cache = 1024
key_buffer_size = 128M
#show global status like 'Max_used_connections'
max_connections = 100
#determine how many thread MySQL keep in memory to handle new conn
#100 - ((Threads_created/Connections)*100)
thread_cache_size = 50
#max size of what is being cached see SHOW GLOBAL STATUS LIKE 'Qc%'
#query_cache_limit = 2M
query_cache_size = 0
query_cache_type = 0
#innodb tuning
innodb_buffer_pool_size = 4G
innodb_buffer_pool_instances = 2
innodb_log_file_size = 1G
innodb_log_buffer_size = 16MB
innodb_flush_log_at_trx_commit = 2
innodb_file_per_table
innodb_flush_method = O_DIRECT
innodb_read_io_threads = 64
innodb_write_io_threads = 64
innodb_thread_concurrency = 0
これまでのところ、私はしようとしました：
1）query_cache_sizeを変更して、CPU使用率に影響があったことを確認します。そこから何のメリットも得られなかったので、無効にしました。
2）キャッシュヒット率を向上させるためにthread_cacheを変更します。 Threads_createdのバリエーションはないので、50にすることにしました。
3）innodb_buffer_pool_size = 4G（合計8Gのうち）
Rolandoのクエリを実行する：
SELECT CEILING(Total_InnoDB_Bytes*1.6/POWER(1024,3)) RIBPS FROM
(SELECT SUM(data_length+index_length) Total_InnoDB_Bytes FROM
information_schema.tables WHERE engine='InnoDB') A;
mycaseで2Gを返します。そこで、innodb_read_io_threads = 64とinnodb_write_io_threads = 64の2つのバッファプールインスタンスを用意することにしました。
これから何も得られませんでした。
4）innodb_log_file_sizeをプールの25％に調整し、trx_commitを2にします。
まだ改善なし。
通常の操作モードでのinnodbステータス出力は（読み取り可能な方法で貼り付けようとしています）です。
mysql> show engine innodb status\G
*************************** 1. row ***************************
Type: InnoDB
Name:
Status:
=====================================
140420 15:41:43 INNODB MONITOR OUTPUT
=====================================
Per second averages calculated from the last 38 seconds
-----------------
BACKGROUND THREAD
-----------------
srv_master_thread loops: 62 1_second, 61 sleeps, 6 10_second, 1 background, 1 flush
srv_master_thread log flush and writes: 62
----------
SEMAPHORES
----------
OS WAIT ARRAY INFO: reservation count 722, signal count 2177
Mutex spin waits 351436, rounds 271903, OS waits 201
RW-shared spins 1069, rounds 12114, OS waits 242
RW-excl spins 479, rounds 10793, OS waits 234
Spin rounds per wait: 0.77 mutex, 11.33 RW-shared, 22.53 RW-excl
------------
TRANSACTIONS
------------
Trx id counter A6BFB
Purge done for trx's n:o < A373C undo n:o < 0
History list length 8780
LIST OF TRANSACTIONS FOR EACH SESSION:
---TRANSACTION A6BB0, not started
MySQL thread id 80, OS thread handle 0x7f4fb7c69700, query id 149238 localhost data
---TRANSACTION A6BD2, not started
MySQL thread id 86, OS thread handle 0x7f4fb7ae3700, query id 149642 localhost data
---TRANSACTION A6BC9, not started
MySQL thread id 78, OS thread handle 0x7f4fb7ceb700, query id 149544 localhost data
---TRANSACTION A6BB8, not started
MySQL thread id 70, OS thread handle 0x7f4fb7ef3700, query id 149353 localhost data
---TRANSACTION A6BD6, not started
MySQL thread id 73, OS thread handle 0x7f4fb7e30700, query id 149674 localhost data
---TRANSACTION A6BBB, not started
MySQL thread id 79, OS thread handle 0x7f4fb7caa700, query id 149298 localhost data
---TRANSACTION A6BC0, not started
MySQL thread id 84, OS thread handle 0x7f4fb7b65700, query id 149379 localhost data
---TRANSACTION A6BCF, not started
MySQL thread id 63, OS thread handle 0x7f4fb80ba700, query id 149574 localhost data
---TRANSACTION A6BCC, not started
MySQL thread id 61, OS thread handle 0x7f5112b16700, query id 149616 localhost data
---TRANSACTION A6BC6, not started
MySQL thread id 58, OS thread handle 0x7f5112bd9700, query id 149498 localhost data
---TRANSACTION 0, not started
MySQL thread id 47, OS thread handle 0x7f5112c1a700, query id 149675 localhost savas
show engine innodb status
---TRANSACTION A6BF9, ACTIVE 0 sec
mysql tables in use 1, locked 0
MySQL thread id 62, OS thread handle 0x7f5112ad5700, query id 149649 localhost data Sending data
SELECT id FROM tracker WHERE domain_id=2 AND visited='Y' AND stop_visit='N' AND NOW()>=addtime(updated,sec_to_time('43200')) limit 100
Trx read view will not see trx with id >= A6BFA, sees < A3706
---TRANSACTION A6BF3, ACTIVE 0 sec
2 lock struct(s), heap size 376, 1 row lock(s)
MySQL thread id 81, OS thread handle 0x7f4fb7c28700, query id 149612 localhost data
Trx read view will not see trx with id >= A6BF4, sees < A3706
---TRANSACTION A6BEE, ACTIVE 0 sec
2 lock struct(s), heap size 376, 1 row lock(s)
MySQL thread id 75, OS thread handle 0x7f4fb7dae700, query id 149515 localhost data
Trx read view will not see trx with id >= A6BEF, sees < A3706
---TRANSACTION A6BEB, ACTIVE 0 sec
2 lock struct(s), heap size 376, 1 row lock(s)
MySQL thread id 82, OS thread handle 0x7f4fb7be7700, query id 149465 localhost data
Trx read view will not see trx with id >= A6BEC, sees < A3706
---TRANSACTION A6BE8, ACTIVE 0 sec
2 lock struct(s), heap size 376, 1 row lock(s)
MySQL thread id 60, OS thread handle 0x7f5112b57700, query id 149449 localhost data
Trx read view will not see trx with id >= A6BE9, sees < A3706
---TRANSACTION A6BE5, ACTIVE 0 sec
2 lock struct(s), heap size 376, 1 row lock(s)
MySQL thread id 59, OS thread handle 0x7f5112b98700, query id 149419 localhost data
Trx read view will not see trx with id >= A6BE6, sees < A3706
---TRANSACTION A6BE4, ACTIVE 0 sec
2 lock struct(s), heap size 376, 1 row lock(s)
MySQL thread id 83, OS thread handle 0x7f4fb7ba6700, query id 149420 localhost data
Trx read view will not see trx with id >= A6BE5, sees < A3706
---TRANSACTION A6BDC, ACTIVE 0 sec
2 lock struct(s), heap size 376, 1 row lock(s)
MySQL thread id 71, OS thread handle 0x7f4fb7eb2700, query id 149327 localhost data
Trx read view will not see trx with id >= A6BDD, sees < A3706
---TRANSACTION A6BD9, ACTIVE 0 sec
2 lock struct(s), heap size 376, 1 row lock(s)
MySQL thread id 65, OS thread handle 0x7f4fb8038700, query id 149312 localhost data
Trx read view will not see trx with id >= A6BDA, sees < A3706
---TRANSACTION A6BB7, ACTIVE 0 sec
2 lock struct(s), heap size 376, 1 row lock(s)
MySQL thread id 68, OS thread handle 0x7f4fb7f75700, query id 149058 localhost data
Trx read view will not see trx with id >= A6BB8, sees < A3706
---TRANSACTION A3727, ACTIVE 63 sec
MySQL thread id 96, OS thread handle 0x7f4fb7859700, query id 48112 localhost data
Trx read view will not see trx with id >= A3728, sees < A3700
---TRANSACTION A3726, ACTIVE 63 sec
MySQL thread id 97, OS thread handle 0x7f4fb7818700, query id 47827 localhost data
Trx read view will not see trx with id >= A3727, sees < A3700
---TRANSACTION A3725, ACTIVE 63 sec
MySQL thread id 95, OS thread handle 0x7f4fb789a700, query id 47424 localhost data
Trx read view will not see trx with id >= A3726, sees < A3700
---TRANSACTION A3724, ACTIVE 63 sec
MySQL thread id 85, OS thread handle 0x7f4fb7b24700, query id 47707 localhost data
Trx read view will not see trx with id >= A3725, sees < A3700
---TRANSACTION A3723, ACTIVE 63 sec
MySQL thread id 89, OS thread handle 0x7f4fb7a20700, query id 47625 localhost data
Trx read view will not see trx with id >= A3724, sees < A3700
---TRANSACTION A3722, ACTIVE 63 sec
MySQL thread id 92, OS thread handle 0x7f4fb795d700, query id 48674 localhost data
Trx read view will not see trx with id >= A3723, sees < A3700
---TRANSACTION A3721, ACTIVE 63 sec
MySQL thread id 93, OS thread handle 0x7f4fb791c700, query id 47449 localhost data
Trx read view will not see trx with id >= A3722, sees < A3700
---TRANSACTION A3720, ACTIVE 63 sec
MySQL thread id 90, OS thread handle 0x7f4fb79df700, query id 48764 localhost data
Trx read view will not see trx with id >= A3721, sees < A3700
---TRANSACTION A371F, ACTIVE 63 sec
MySQL thread id 94, OS thread handle 0x7f4fb78db700, query id 48320 localhost data
Trx read view will not see trx with id >= A3720, sees < A3700
---TRANSACTION A371E, ACTIVE 63 sec
MySQL thread id 91, OS thread handle 0x7f4fb799e700, query id 48109 localhost data
Trx read view will not see trx with id >= A371F, sees < A3700
---TRANSACTION A371D, ACTIVE 63 sec
MySQL thread id 76, OS thread handle 0x7f4fb7d6d700, query id 48220 localhost data
Trx read view will not see trx with id >= A371E, sees < A3700
---TRANSACTION A3718, ACTIVE 63 sec
MySQL thread id 88, OS thread handle 0x7f4fb7a61700, query id 48238 localhost data
Trx read view will not see trx with id >= A3719, sees < A3700
---TRANSACTION A3716, ACTIVE 63 sec
MySQL thread id 87, OS thread handle 0x7f4fb7aa2700, query id 48036 localhost data
Trx read view will not see trx with id >= A3717, sees < A3700
---TRANSACTION A3711, ACTIVE 63 sec
MySQL thread id 77, OS thread handle 0x7f4fb7d2c700, query id 48232 localhost data
Trx read view will not see trx with id >= A3712, sees < A3700
---TRANSACTION A370E, ACTIVE 63 sec
MySQL thread id 72, OS thread handle 0x7f4fb7e71700, query id 47602 localhost data
Trx read view will not see trx with id >= A370F, sees < A3700
---TRANSACTION A370C, ACTIVE 63 sec
MySQL thread id 74, OS thread handle 0x7f4fb7def700, query id 48101 localhost data
Trx read view will not see trx with id >= A370D, sees < A3700
---TRANSACTION A370B, ACTIVE 63 sec
MySQL thread id 69, OS thread handle 0x7f4fb7f34700, query id 48102 localhost data
Trx read view will not see trx with id >= A370C, sees < A3700
---TRANSACTION A3708, ACTIVE 63 sec
MySQL thread id 67, OS thread handle 0x7f4fb7fb6700, query id 48748 localhost data
Trx read view will not see trx with id >= A3709, sees < A3700
---TRANSACTION A3707, ACTIVE 63 sec
MySQL thread id 66, OS thread handle 0x7f4fb7ff7700, query id 48263 localhost data
Trx read view will not see trx with id >= A3708, sees < A3700
---TRANSACTION A3706, ACTIVE 63 sec
MySQL thread id 64, OS thread handle 0x7f4fb8079700, query id 48314 localhost data
Trx read view will not see trx with id >= A3707, sees < A3700
--------
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 (read thread)
I/O thread 7 state: waiting for completed aio requests (read thread)
I/O thread 8 state: waiting for completed aio requests (read thread)
I/O thread 9 state: waiting for completed aio requests (read thread)
I/O thread 10 state: waiting for completed aio requests (read thread)
I/O thread 11 state: waiting for completed aio requests (read thread)
I/O thread 12 state: waiting for completed aio requests (read thread)
I/O thread 13 state: waiting for completed aio requests (read thread)
I/O thread 14 state: waiting for completed aio requests (read thread)
I/O thread 15 state: waiting for completed aio requests (read thread)
I/O thread 16 state: waiting for completed aio requests (read thread)
I/O thread 17 state: waiting for completed aio requests (read thread)
I/O thread 18 state: waiting for completed aio requests (read thread)
I/O thread 19 state: waiting for completed aio requests (read thread)
I/O thread 20 state: waiting for completed aio requests (read thread)
I/O thread 21 state: waiting for completed aio requests (read thread)
I/O thread 22 state: waiting for completed aio requests (read thread)
I/O thread 23 state: waiting for completed aio requests (read thread)
I/O thread 24 state: waiting for completed aio requests (read thread)
I/O thread 25 state: waiting for completed aio requests (read thread)
I/O thread 26 state: waiting for completed aio requests (read thread)
I/O thread 27 state: waiting for completed aio requests (read thread)
I/O thread 28 state: waiting for completed aio requests (read thread)
I/O thread 29 state: waiting for completed aio requests (read thread)
I/O thread 30 state: waiting for completed aio requests (read thread)
I/O thread 31 state: waiting for completed aio requests (read thread)
I/O thread 32 state: waiting for completed aio requests (read thread)
I/O thread 33 state: waiting for completed aio requests (read thread)
I/O thread 34 state: waiting for completed aio requests (read thread)
I/O thread 35 state: waiting for completed aio requests (read thread)
I/O thread 36 state: waiting for completed aio requests (read thread)
I/O thread 37 state: waiting for completed aio requests (read thread)
I/O thread 38 state: waiting for completed aio requests (read thread)
I/O thread 39 state: waiting for completed aio requests (read thread)
I/O thread 40 state: waiting for completed aio requests (read thread)
I/O thread 41 state: waiting for completed aio requests (read thread)
I/O thread 42 state: waiting for completed aio requests (read thread)
I/O thread 43 state: waiting for completed aio requests (read thread)
I/O thread 44 state: waiting for completed aio requests (read thread)
I/O thread 45 state: waiting for completed aio requests (read thread)
I/O thread 46 state: waiting for completed aio requests (read thread)
I/O thread 47 state: waiting for completed aio requests (read thread)
I/O thread 48 state: waiting for completed aio requests (read thread)
I/O thread 49 state: waiting for completed aio requests (read thread)
I/O thread 50 state: waiting for completed aio requests (read thread)
I/O thread 51 state: waiting for completed aio requests (read thread)
I/O thread 52 state: waiting for completed aio requests (read thread)
I/O thread 53 state: waiting for completed aio requests (read thread)
I/O thread 54 state: waiting for completed aio requests (read thread)
I/O thread 55 state: waiting for completed aio requests (read thread)
I/O thread 56 state: waiting for completed aio requests (read thread)
I/O thread 57 state: waiting for completed aio requests (read thread)
I/O thread 58 state: waiting for completed aio requests (read thread)
I/O thread 59 state: waiting for completed aio requests (read thread)
I/O thread 60 state: waiting for completed aio requests (read thread)
I/O thread 61 state: waiting for completed aio requests (read thread)
I/O thread 62 state: waiting for completed aio requests (read thread)
I/O thread 63 state: waiting for completed aio requests (read thread)
I/O thread 64 state: waiting for completed aio requests (read thread)
I/O thread 65 state: waiting for completed aio requests (read thread)
I/O thread 66 state: waiting for completed aio requests (write thread)
I/O thread 67 state: waiting for completed aio requests (write thread)
I/O thread 68 state: waiting for completed aio requests (write thread)
I/O thread 69 state: waiting for completed aio requests (write thread)
I/O thread 70 state: waiting for completed aio requests (write thread)
I/O thread 71 state: waiting for completed aio requests (write thread)
I/O thread 72 state: waiting for completed aio requests (write thread)
I/O thread 73 state: waiting for completed aio requests (write thread)
I/O thread 74 state: waiting for completed aio requests (write thread)
I/O thread 75 state: waiting for completed aio requests (write thread)
I/O thread 76 state: waiting for completed aio requests (write thread)
I/O thread 77 state: waiting for completed aio requests (write thread)
I/O thread 78 state: waiting for completed aio requests (write thread)
I/O thread 79 state: waiting for completed aio requests (write thread)
I/O thread 80 state: waiting for completed aio requests (write thread)
I/O thread 81 state: waiting for completed aio requests (write thread)
I/O thread 82 state: waiting for completed aio requests (write thread)
I/O thread 83 state: waiting for completed aio requests (write thread)
I/O thread 84 state: waiting for completed aio requests (write thread)
I/O thread 85 state: waiting for completed aio requests (write thread)
I/O thread 86 state: waiting for completed aio requests (write thread)
I/O thread 87 state: waiting for completed aio requests (write thread)
I/O thread 88 state: waiting for completed aio requests (write thread)
I/O thread 89 state: waiting for completed aio requests (write thread)
I/O thread 90 state: waiting for completed aio requests (write thread)
I/O thread 91 state: waiting for completed aio requests (write thread)
I/O thread 92 state: waiting for completed aio requests (write thread)
I/O thread 93 state: waiting for completed aio requests (write thread)
I/O thread 94 state: waiting for completed aio requests (write thread)
I/O thread 95 state: waiting for completed aio requests (write thread)
I/O thread 96 state: waiting for completed aio requests (write thread)
I/O thread 97 state: waiting for completed aio requests (write thread)
I/O thread 98 state: waiting for completed aio requests (write thread)
I/O thread 99 state: waiting for completed aio requests (write thread)
I/O thread 100 state: waiting for completed aio requests (write thread)
I/O thread 101 state: waiting for completed aio requests (write thread)
I/O thread 102 state: waiting for completed aio requests (write thread)
I/O thread 103 state: waiting for completed aio requests (write thread)
I/O thread 104 state: waiting for completed aio requests (write thread)
I/O thread 105 state: waiting for completed aio requests (write thread)
I/O thread 106 state: waiting for completed aio requests (write thread)
I/O thread 107 state: waiting for completed aio requests (write thread)
I/O thread 108 state: waiting for completed aio requests (write thread)
I/O thread 109 state: waiting for completed aio requests (write thread)
I/O thread 110 state: waiting for completed aio requests (write thread)
I/O thread 111 state: waiting for completed aio requests (write thread)
I/O thread 112 state: waiting for completed aio requests (write thread)
I/O thread 113 state: waiting for completed aio requests (write thread)
I/O thread 114 state: waiting for completed aio requests (write thread)
I/O thread 115 state: waiting for completed aio requests (write thread)
I/O thread 116 state: waiting for completed aio requests (write thread)
I/O thread 117 state: waiting for completed aio requests (write thread)
I/O thread 118 state: waiting for completed aio requests (write thread)
I/O thread 119 state: waiting for completed aio requests (write thread)
I/O thread 120 state: waiting for completed aio requests (write thread)
I/O thread 121 state: waiting for completed aio requests (write thread)
I/O thread 122 state: waiting for completed aio requests (write thread)
I/O thread 123 state: waiting for completed aio requests (write thread)
I/O thread 124 state: waiting for completed aio requests (write thread)
I/O thread 125 state: waiting for completed aio requests (write thread)
I/O thread 126 state: waiting for completed aio requests (write thread)
I/O thread 127 state: waiting for completed aio requests (write thread)
I/O thread 128 state: waiting for completed aio requests (write thread)
I/O thread 129 state: waiting for completed aio requests (write thread)
Pending normal aio reads: 0 [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0] , aio writes: 0 [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 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
1381 OS file reads, 6437 OS file writes, 98 OS fsyncs
0.47 reads/s, 16384 avg bytes/read, 103.02 writes/s, 1.55 fsyncs/s
-------------------------------------
INSERT BUFFER AND ADAPTIVE HASH INDEX
-------------------------------------
Ibuf: size 1, free list len 3, seg size 5, 1 merges
merged operations:
insert 7, delete mark 0, delete 0
discarded operations:
insert 0, delete mark 0, delete 0
Hash table size 8850461, node heap has 9 buffer(s)
129480.12 hash searches/s, 1874.61 non-hash searches/s
---
LOG
---
Log sequence number 2208664963
Log flushed up to 2208626326
Last checkpoint at 2206051147
0 pending log writes, 0 pending chkp writes
6364 log i/o's done, 101.63 log i/o's/second
----------------------
BUFFER POOL AND MEMORY
----------------------
Total memory allocated 4395630592; in additional pool allocated 0
Dictionary memory allocated 109470
Buffer pool size 262143
Free buffers 260626
Database pages 1508
Old database pages 556
Modified db pages 447
Pending reads 0
Pending writes: LRU 0, flush list 0, single page 0
Pages made young 0, not young 0
0.00 youngs/s, 0.00 non-youngs/s
Pages read 1359, created 149, written 66
0.47 reads/s, 3.53 creates/s, 1.18 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: 1508, unzip_LRU len: 0
I/O sum[0]:cur[26], unzip sum[0]:cur[0]
----------------------
INDIVIDUAL BUFFER POOL INFO
----------------------
---BUFFER POOL 0
Buffer pool size 131072
Free buffers 130261
Database pages 806
Old database pages 315
Modified db pages 242
Pending reads 0
Pending writes: LRU 0, flush list 0, single page 0
Pages made young 0, not young 0
0.00 youngs/s, 0.00 non-youngs/s
Pages read 759, created 47, written 34
0.42 reads/s, 0.84 creates/s, 0.61 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: 806, unzip_LRU len: 0
I/O sum[0]:cur[13], unzip sum[0]:cur[0]
---BUFFER POOL 1
Buffer pool size 131071
Free buffers 130365
Database pages 702
Old database pages 241
Modified db pages 205
Pending reads 0
Pending writes: LRU 0, flush list 0, single page 0
Pages made young 0, not young 0
0.00 youngs/s, 0.00 non-youngs/s
Pages read 600, created 102, written 32
0.05 reads/s, 2.68 creates/s, 0.58 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: 702, unzip_LRU len: 0
I/O sum[0]:cur[13], unzip sum[0]:cur[0]
--------------
ROW OPERATIONS
--------------
0 queries inside InnoDB, 0 queries in queue
31 read views open inside InnoDB
Main thread process no. 14441, id 139980400486144, state: sleeping
Number of rows inserted 0, updated 6750, deleted 0, read 352960
0.00 inserts/s, 108.23 updates/s, 0.00 deletes/s, 5625.48 reads/s
----------------------------
END OF INNODB MONITOR OUTPUT
============================
私が何週間も戦っていたパフォーマンスの問題をどのように解決したかを説明します。遠慮なく批判してください。結果は困っている人にとってより良いものになり得ます。
最初に「High Performance MySQL」という本を読みました。彼らは最初からプロファイリングの方法を公開しているので、素晴らしい本です。基本的に、最初の2〜3章を読み終えると、掘り出しを開始するのに十分なツールが手に入ります。私はほとんどのプロファイリング方法を知りませんでした、そして多くを学びました。
_query_log_time=0_を設定して、query_logから掘り始めることにしました。次に、問題を引き起こしていたクエリを選択しました。実際、すべてのクエリにインデックスが付けられたため、選択肢は1つしかありませんでしたが、この特定の選択肢は大きなテーブルで作業していました。ここですべてを行った。
ターゲットテーブルは次のとおりです。
_+------------+---------------+------+-----+-------------------+----------------+
| Field | Type | Null | Key | Default | Extra |
+------------+---------------+------+-----+-------------------+----------------+
| id | int(11) | NO | PRI | NULL | auto_increment |
| domain_id | int(11) | NO | MUL | NULL | |
| url | varchar(250) | NO | UNI | 0 | |
| visited | enum('Y','N') | NO | | N | |
| updated | timestamp | NO | | CURRENT_TIMESTAMP | |
| hits | smallint(6) | NO | | 0 | |
| stop_visit | enum('Y','N') | NO | | N | |
+------------+---------------+------+-----+-------------------+----------------+
_疑わしいクエリは次のとおりです。
_SELECT id FROM tracker WHERE updated<=NOW() and domain_id=2 and stop_visit='N' LIMIT 1;
_（updated、domain_id、stop_visit）にBTREEインデックスがあったため、説明計画は何も提供しませんでした。次に、次のようにプロファイリングをクエリしてみました。
_ SET profiling=1;
SHOW profiles;
SET @query_id=1
SELECT STATE, SUM(DURATION) AS Total_R,
ROUND(
100 * SUM(DURATION) /
(SELECT SUM(DURATION)
FROM INFORMATION_SCHEMA.PROFILING
WHERE QUERY_ID = @query_id
), 2) AS Pct_R,
COUNT(*) AS Calls,
SUM(DURATION) / COUNT(*) AS "R/Call"
FROM INFORMATION_SCHEMA.PROFILING
WHERE QUERY_ID = @query_id
GROUP BY STATE
ORDER BY Total_R DESC;
_何も問題はなく、クエリは0.001未満のタイミングで実行されていました。一時テーブルもインデックスも使用されていません...すべて問題はないように見えますが、明らかにそこにあることがわかっている根本的な問題があります。
_SHOW STATUS_と_FLUSH STATUS_は本当に奇妙な何かを示しました：
_ FLUSH status;
SELECT id FROM tracker WHERE updated<=NOW() and domain_id=2 and stop_visit='N' LIMIT 1;
show status where variable_name like 'Created%' or variable_name like 'Handler%';
+----------------------------+-------+
| Variable_name | Value |
+----------------------------+-------+
| Created_tmp_disk_tables | 0 |
| Created_tmp_files | 6 |
| Created_tmp_tables | 0 |
| Handler_commit | 0 |
| Handler_delete | 0 |
| Handler_discover | 0 |
| Handler_prepare | 0 |
| Handler_read_first | 0 |
| Handler_read_key | 0 |
| Handler_read_last | 0 |
| Handler_read_next | 44687 |
| Handler_read_prev | 0 |
| Handler_read_rnd | 0 |
| Handler_read_rnd_next | 0 |
| Handler_rollback | 0 |
| Handler_savepoint | 0 |
| Handler_savepoint_rollback | 0 |
| Handler_update | 0 |
| Handler_write | 0 |
+----------------------------+-------+
_今、インデックスが選択的であるように調整されたときにHandler_read_nextがなぜそれほど高いのかと思いました（または私はそう思いました）。まあそうではなかった。さらに重要なことに、私はまだこの質問に対する答えがありません。ランダムな試行を重ねた後、ENUM列（stop_visit）がこの非常に高いHandler_read_next値を引き起こしていることがわかりました。データ型をtinyint [0,1]またはchar（1）['Y'、 'N']に変更しても、何のメリットもありませんでした。
この時点で、私はすべてを壊し、習得した知識でゼロからやり直すことにしました。これにより、最初のテーブルが次のように変更されました。
_+-----------+---------------------+------+-----+-------------------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-----------+---------------------+------+-----+-------------------+----------------+
| id | bigint(20) unsigned | NO | PRI | NULL | auto_increment |
| url_crc | int(10) unsigned | NO | MUL | NULL | |
| updated | timestamp | NO | MUL | CURRENT_TIMESTAMP | |
| domain_id | tinyint(3) unsigned | NO | | NULL | |
| owner | int(10) unsigned | NO | MUL | 0 | |
| url | varchar(255) | NO | | NULL | |
| hits | tinyint(3) unsigned | NO | | 0 | |
+-----------+---------------------+------+-----+-------------------+----------------+
_以前の複数列インデックスは、単一列インデックスALTER table tracker add index idx_updated (updated)になりました。
結果は、Handler_read_next操作を行わないクエリでした。代わりに、Handler_read_keyおよびHandler_read_firstを1ずつ正常に増分していました。
VARCHARデータ型へのアクセスに使用されるこの本で説明されている方法を使用することにより、もう1つの不明瞭な問題が解決されました。以前にurl列にこのUNIQUEインデックスがありましたが、この大きなテーブルでINSERT IGNOREを使用して、UNIQUE制約を信頼するのが良い方法だと思っていました。したがって、Mysqlがこの新しいURLを挿入するためにすべての行を通過しなければならない場合、それは苦痛になるでしょう。理由は、平均50の同時クライアントで（最初のクエリが完了するとすぐに）0.001ごとに約40 INSERT IGNOREです。
そこで、crc32整数インデックスを使用してこの動作を変更しました。そして、次のように読み取りを実行します：
_ SELECT * from tracker WHERE url_crc=crc32('http://google.com') and url='http://google.com'
_まだ0.001ごとに40のSELECTがありますが、少なくとも簡単にプロファイルできます。だから私は今のところこれに固執することにしました。
これらの変更がすべて行われた後、すべての作業を検証する時が来ました。
もう一度、この素晴らしい本から、3つの簡単な方法：
_> while true; do sleep 1; mysql -e 'SHOW PROCESSLIST\G' | grep State: | sort | uniq -c | sort -rn; done
> mysqladmin ext -i1 | awk 'BEGIN{printf "%5s %5s %5s %5s %5s %5s %5s\n","QPS","Thcon","Thrun","Opentb","tmp_tbl","FreePages","Bytessent"}/Queries/{q=$4-qp;qp=$4}/Threads_connected/{tc=$4}/Created_tmp_disk_tables/{tmp=$4}/Opened_tables/{ot=$4}/Innodb_buffer_pool_pages_free/{pf=$4}/Bytes_sent/{bs=$4}/Threads_running/{printf "%5d %5d %5d %5d %5d %10d %10d\n",q,tc,$4,ot,tmp,pf,bs}'
> awk '/^# Time:/{print $3, $4, c;c=0}/^# User/{c++}' mysql-slow.log
_最初のコマンドは、正常ではない状態を見つけるのに役立ちます。これは、より高度なプロファイリングの始まりでもありますが、ここではそれらの側面については説明しません。このコマンドは、クエリキャッシュが良いことよりも害を及ぼしていることを知るのに役立ちました。
2番目のコマンドは、サーバーのステータスをチェックし、それがどのように進化しているかを確認するために作成されます。出力を調べるだけで問題をすばやく見つけることができます。
_QPS Th_con Th_run Opened_files tmp_disk free_pages bytes_sent
466 22 7 276 54 120658 30110619
401 22 6 276 54 120657 30145343
405 22 9 276 54 120657 30179509
=>85 22 5 276 54 120658 30196291
_QPSが85に突然下がった場合は、何か問題が発生していることを示しています。私の場合、query_logは大量の更新を明らかにしました。これは、MySQLのクールな方法でフラッシュされなかったキャッシュテーブルが原因でした。
これらすべての改善により、ルーター_kernel: [539677.201824] nf_conntrack: table full, dropping packet._をDoSすることができました。それは最初だった：p
ですから、関連するすべての投稿について、素晴らしい本「High Performance MySQL」の作者とここのコミュニティに感謝するときがきたと思います。