MySQL（MariaDB-10.0.16-MariaDB-1（Debian）奇怪的性能問題

Question

我在Dual Xeon CPU上運行版本10.0.16-MariaDB-1（Debian GNU / Linux 8.1（jessie）），共有32個核，具有128 GB的RAM。 這是一台專用的數據庫服務器，最近已從Percona數據庫服務器遷移過來。 我的配置看起來像這樣，

################################################################################
# DATE: 19-01-2014
# DESCRIPTION: MySQL config
# RAM: 128GB RAM dedicated server
# Connections: 1000 connections
################################################################################

[mysql]
# CLIENT #
port                           = 1979
socket                         = /var/run/mysqld/mysqld.sock

[mysqld]

## Files
back_log            = 300
open-files-limit        = 8192
#open-files             = 1024  

# GENERAL #
user                           = mysql
default-storage-engine         = InnoDB
port                           = 1979
socket                         = /var/run/mysqld/mysqld.sock
pid-file                       = /var/run/mysqld/mysql.pid

# DATA STORAGE #
datadir                        = /var/lib/mysql

# LOGGING #
log-error                      = /var/log/mysql/mysql-error.log
log-queries-not-using-indexes  = 0
slow-query-log                 = 0
slow-query-log-file            = /var/log/mysql/mysql-slow.log

## Per-Thread Buffers * (max_connections) = total per-thread mem usage
thread_stack            = 512K    #default: 32bit: 192K, 64bit: 256K
sort_buffer_size        = 2M      #default: 2M, larger may cause perf issues
read_buffer_size        = 2M      #default: 128K, change in increments of 4K
read_rnd_buffer_size        = 2M      #default: 256K                
join_buffer_size        = 2M      #default: 128K
binlog_cache_size       = 128K    #default: 32K, size of buffer to hold TX queries
## total per-thread buffer memory usage: 17664000K = 17.250GB

## Query Cache
query_cache_size        = 64M   #global buffer
query_cache_limit               = 2M    #max query result size to put in cache

## Connections
max_connections = 900   #multiplier for memory usage via per-thread buffers
max_connect_errors      = 1000  #default: 10
concurrent_insert = 2
connect_timeout         = 10    #default -5.1.22: 5, +5.1.22: 10
max_allowed_packet      = 32M   #max size of incoming data to allow

## Default Table Settings
sql_mode            = NO_AUTO_CREATE_USER

## Table and TMP settings
max_heap_table_size         = 1G    #recommend same size as tmp_table_size
bulk_insert_buffer_size         = 1G    #recommend same size as tmp_table_size
tmp_table_size                  = 1G    #recommend 1G min
tmpdir                         = /dev/shm        #Recommend using RAMDISK for tmpdir

## Table cache settings
#table_cache            = 512   #5.0.x <default: 64>
#table_open_cache       = 512   #5.1.x, 5.5.x <default: 64>

query-cache-type = 1

## Thread settings
thread_concurrency      = 32  #recommend 2x CPU cores
thread_cache_size       = 400 #recommend 5% of max_connections

## InnoDB Plugin Independent Settings
innodb_data_home_dir            = /var/lib/mysql
innodb_data_file_path       = ibdata1:128M;ibdata2:10M:autoextend
innodb_log_file_size        = 768M  #64G_RAM+ = 768, 24G_RAM+ = 512, 8G_RAM+ = 256, 2G_RAM+ = 128 
innodb_log_files_in_group   = 4 #combined size of all logs <4GB. <2G_RAM = 2, >2G_RAM = 4
innodb_buffer_pool_size     = 96G   #global buffer
innodb_additional_mem_pool_size = 8M    #global buffer
innodb_status_file          #extra reporting
innodb_file_per_table           #enable always
innodb_flush_log_at_trx_commit = 2
innodb_table_locks      = 0 #preserve table locks
innodb_log_buffer_size      = 128M  #global buffer
innodb_lock_wait_timeout = 600
#innodb_thread_concurrency = 0
innodb_commit_concurrency = 8   #recommend 4x num disks
innodb_flush_method     = O_DIRECT_NO_FSYNC    #O_DIRECT = local/DAS, O_DSYNC = SAN/iSCSI
innodb_support_xa       = 0        #recommend 0, disable xa to negate extra disk flush
innodb_fast_shutdown = 1
skip-innodb-doublewrite
skip-host-cache
# skip-name-resolve

## Binlog sync settings
## XA transactions = 1, otherwise set to 0 for best performance
sync_binlog         = 0

## TX Isolation
#transaction-isolation      = REPEATABLE-READ #REPEATABLE-READ req for ACID, SERIALIZABLE req XA

## Per-Thread Buffer memory utilization equation:
#(read_buffer_size + read_rnd_buffer_size + sort_buffer_size + thread_stack + join_buffer_size + binlog_cache_size) * max_connections

## Replication
#server_id           = 1
#log_bin             = /var/log/mysql/mysql-bin.log
#log_bin_index       = /var/log/mysql/mysql-bin.log.index
#relay_log           = /var/log/mysql/mysql-relay-bin
#relay_log_index     = /var/log/mysql/mysql-relay-bin.index
#expire_logs_days    = 10
#max_binlog_size     = 100M
#log_slave_updates   = 1
#auto-increment-increment = 2
#auto-increment-offset = 1

## Global Buffer memory utilization equation:
# innodb_buffer_pool_size + innodb_additional_mem_pool_size + innodb_log_buffer_size + key_buffer_size + query_cache_size
long_query_time = 3
innodb_checksum_algorithm=NONE
interactive_timeout = 300
wait_timeout = 40
myisam_repair_threads = 8
myisam-block-size = 8096
innodb_adaptive_hash_index = off
innodb_use_sys_malloc
innodb_sync_array_size = 4
innodb_read_ahead_threshold = 56
innodb_purge_threads = 4
innodb_adaptive_flushing = off
innodb_use_native_aio = off
innodb_random_read_ahead
optimizer_search_depth = 24
table_definition_cache = 400
table_open_cache = 2048
delay-key-write = ALL
innodb_checksum_algorithm = innodb
innodb_write_io_threads = 64
innodb_read_io_threads = 64
thread_pool_size = 16
thread_handling = pool-of-threads

innodb_disable_sort_file_cache
innodb_buffer_pool_instances = 32
innodb_adaptive_hash_index = off

[mysqldump]
quick
quote-names
max_allowed_packet      = 128M

我有多個主機連接到服務器並啟動查詢。 我面臨的問題是，數據庫服務器隨機停止接受連接。 所有連接開始堆積，並在大約3或5秒鍾內恢復正常。 當我運行show processlist我看到很多連接堆積起來等待connected但是由於DB服務器停止接受連接，最終連接池已滿，不允許再有其他連接。

在此停電期間，我無法查看數據庫服務器上發生的情況，因為即使連接已經建立，我也不會提供任何信息。 iostat -d -x 1不會顯示磁盤異常，CPU也大部分處於空閑狀態。 TCP連接堆積如山，因為客戶端需要打開數據，因為它們需要推送數據。

我無法弄清楚這里出了什么問題。 這是我的數據庫，機器或配置專用的東西嗎？ 在這里，我需要一些幫助，以查找在何處以及尋找什么以找出並糾正該問題。

謝謝。

Answer 1

thread_stack = 512K＃默認：32位：192K，64位：256K

我還沒有聽說需要超過256K。 您是否發現需要512K？ 和...一起

max_connections = 900

您可能需要500MB的進程。 （當然，這不是什么大問題，因為您擁有128GB的內存。）

回到問題...

用long_query_time = 1打開slow_log。在下一次出現之后，對slowlog運行pt-query-digest。 那里可能會有一些驚喜。 請注意，在3-5秒的暫停時間內掛起的查詢將注冊為花費幾秒鍾，即使它們只需要幾毫秒。 仍然存在無法將手指指向暫停的真正原因的風險。