title: Mysql Error writing file /tmp/ Errcode 28 in phpmyadmin
body: <p>Every time I try to select from my Mysql table with million plus rows in phpmyadmin I receive the following error:
  "Error writing file /tmp/ Errcode 28"</p>
  
  <p>Server Stats:</p>
  
  <pre><code>Filesystem      Size  Used Avail Use% Mounted on
  /dev/vda1        30G   21G  7.5G  74% /
  tmpfs           939M     0  939M   0% /dev/shm
  /usr/tmpDSK     3.0G  176M  2.6G   7% /tmp
  </code></pre>
  
  <p>my.cnf</p>
  
  <pre><code>[mysqld]
  tmpdir=/tmp
  innodb_file_per_table=1
  open_files_limit=50000
  myisam_use_mmap=1
  
  max_connections = 200
  max_user_connections = 75
  
  join_buffer_size=2M
  sort_buffer_size=2M
  
  table_open_cache = 8000
  
  table_definition_cache = 6000
  max_allowed_packet = 1G
  
  thread_cache_size = 384
  
  query_cache_type = 1
  query_cache_size = 100M
  query_cache_limit = 1M
  
  max_heap_table_size = 50M
  tmp_table_size = 300M
  
  key_buffer_size = 2500M
  
  innodb_buffer_pool_size = 3G
  innodb_log_buffer_size = 32M
  innodb_old_blocks_time=1000
  innodb_concurrency_tickets=5000
  innodb_autoextend_increment=64M
  innodb_open_files=2000
  innodb_stats_on_metadata=0
  
  slow_query_log=1
  slow_query_log_file=mysql-slow.log
  long_query_time=0.1
  </code></pre>
  
  <p>General Statistics --------------------------------------------------</p>
  
  <pre><code>[--] Skipped version check for MySQLTuner script
  [OK] Currently running supported MySQL version 5.5.35-cll
  [OK] Operating on 64-bit architecture
  
  -------- Storage Engine Statistics -------------------------------------------
  [--] Status: +Archive -BDB -Federated +InnoDB -ISAM -NDBCluster
  [--] Data in MyISAM tables: 6G (Tables: 293)
  [--] Data in InnoDB tables: 224K (Tables: 14)
  
  [--] Data in PERFORMANCE_SCHEMA tables: 0B (Tables: 17)
  [!!] Total fragmented tables: 45
  
  -------- Security Recommendations  -------------------------------------------
  [OK] All database users have passwords assigned
  
  -------- Performance Metrics -------------------------------------------------
  [--] Up for: 37m 24s (909 q [0.405 qps], 127 conn, TX: 608K, RX: 75K)
  [--] Reads / Writes: 68% / 32%
  [--] Total buffers: 5.6G global + 4.6M per thread (200 max threads)
  [!!] Maximum possible memory usage: 6.5G (356% of installed RAM)
  [OK] Slow queries: 4% (39/909)
  
  [OK] Highest usage of available connections: 6% (13/200)
  [OK] Key buffer size / total MyISAM indexes: 2.4G/2.4G
  [!!] Key buffer hit rate: 85.3% (685 cached / 101 reads)
  [OK] Query cache efficiency: 47.4% (225 cached / 475 selects)
  [OK] Query cache prunes per day: 0
  [OK] Sorts requiring temporary tables: 0% (0 temp sorts / 12 sorts)
  [OK] Temporary tables created on disk: 11% (2 on disk / 17 total)
  [OK] Thread cache hit rate: 89% (13 created / 127 connections)
  [OK] Table cache hit rate: 98% (379 open / 386 opened)
  [OK] Open file limit used: 1% (666/50K)
  [!!] Table locks acquired immediately: 93%
  [OK] InnoDB data size / buffer pool: 224.0K/3.0G
  </code></pre>
  
  <p>How do I tune the server to manage such tables so the: "Error writing file /tmp/ Errcode 28" does not come up? I have several of such tables.</p>
  
  <p>Thank you.</p>