Eu tive uma pergunta semelhante sobre o estouro de pilha, mas parece ser mais relacionado ao servidor / mysql do que à codificação.
As consultas abaixo são todas executadas instantaneamente em nosso servidor de desenvolvimento, onde podem demorar até 2 minutos e 20 segundos.
O tempo de execução da consulta parece ser afetado pela origem ambígua das cadeias LIKE. Se eles corresponderem de perto a um país que tem poucas correspondências, levará menos tempo, e se você usar algo como 'ge' para a Alemanha - levará mais tempo para ser executado. Mas isso nem sempre funciona assim, às vezes é bastante errático.
O envio de dados parece ser o culpado, mas por que e o que isso significa. Também a memória na produção parece ser bem baixa (memória livre)?
Produção:
Intel Quad Xeon E3-1220 3.1GHz
4GB DDR3
2x 1TB SATA em RAID1
Velocidade de rede 100Mb
Ubuntu
Desenvolvimento
Intel Core i3-2100, 2C / 4T, 3.10GHz
500 GB SATA - No RAID
4GB DDR3
UPDATE 2:
saída do mysqltuner:
[prod]
-------- General Statistics --------------------------------------------------
[--] Skipped version check for MySQLTuner script
[OK] Currently running supported MySQL version 5.1.61-0ubuntu0.10.04.1
[OK] Operating on 64-bit architecture
-------- Storage Engine Statistics -------------------------------------------
[--] Status: +Archive -BDB -Federated +InnoDB -ISAM -NDBCluster
[--] Data in MyISAM tables: 103M (Tables: 180)
[--] Data in InnoDB tables: 491M (Tables: 19)
[!!] Total fragmented tables: 38
-------- Security Recommendations -------------------------------------------
[OK] All database users have passwords assigned
-------- Performance Metrics -------------------------------------------------
[--] Up for: 77d 4h 6m 1s (53M q [7.968 qps], 14M conn, TX: 87B, RX: 12B)
[--] Reads / Writes: 98% / 2%
[--] Total buffers: 58.0M global + 2.7M per thread (151 max threads)
[OK] Maximum possible memory usage: 463.8M (11% of installed RAM)
[OK] Slow queries: 0% (12K/53M)
[OK] Highest usage of available connections: 22% (34/151)
[OK] Key buffer size / total MyISAM indexes: 16.0M/10.6M
[OK] Key buffer hit rate: 98.7% (162M cached / 2M reads)
[OK] Query cache efficiency: 20.7% (7M cached / 36M selects)
[!!] Query cache prunes per day: 3934
[OK] Sorts requiring temporary tables: 1% (3K temp sorts / 230K sorts)
[!!] Joins performed without indexes: 71068
[OK] Temporary tables created on disk: 24% (3M on disk / 13M total)
[OK] Thread cache hit rate: 99% (690 created / 14M connections)
[!!] Table cache hit rate: 0% (64 open / 85M opened)
[OK] Open file limit used: 12% (128/1K)
[OK] Table locks acquired immediately: 99% (16M immediate / 16M locks)
[!!] InnoDB data size / buffer pool: 491.9M/8.0M
-------- Recommendations -----------------------------------------------------
General recommendations:
Run OPTIMIZE TABLE to defragment tables for better performance
Enable the slow query log to troubleshoot bad queries
Adjust your join queries to always utilize indexes
Increase table_cache gradually to avoid file descriptor limits
Variables to adjust:
query_cache_size (> 16M)
join_buffer_size (> 128.0K, or always use indexes with joins)
table_cache (> 64)
innodb_buffer_pool_size (>= 491M)
[dev]
-------- General Statistics --------------------------------------------------
[--] Skipped version check for MySQLTuner script
[OK] Currently running supported MySQL version 5.1.62-0ubuntu0.11.10.1
[!!] Switch to 64-bit OS - MySQL cannot currently use all of your RAM
-------- Storage Engine Statistics -------------------------------------------
[--] Status: +Archive -BDB -Federated +InnoDB -ISAM -NDBCluster
[--] Data in MyISAM tables: 185M (Tables: 632)
[--] Data in InnoDB tables: 967M (Tables: 38)
[!!] Total fragmented tables: 73
-------- Security Recommendations -------------------------------------------
[OK] All database users have passwords assigned
-------- Performance Metrics -------------------------------------------------
[--] Up for: 1d 2h 26m 9s (5K q [0.058 qps], 1K conn, TX: 4M, RX: 1M)
[--] Reads / Writes: 99% / 1%
[--] Total buffers: 58.0M global + 2.7M per thread (151 max threads)
[OK] Maximum possible memory usage: 463.8M (11% of installed RAM)
[OK] Slow queries: 0% (0/5K)
[OK] Highest usage of available connections: 1% (2/151)
[OK] Key buffer size / total MyISAM indexes: 16.0M/18.6M
[OK] Key buffer hit rate: 99.9% (60K cached / 36 reads)
[OK] Query cache efficiency: 44.5% (1K cached / 2K selects)
[OK] Query cache prunes per day: 0
[OK] Sorts requiring temporary tables: 0% (0 temp sorts / 44 sorts)
[OK] Temporary tables created on disk: 24% (162 on disk / 666 total)
[OK] Thread cache hit rate: 99% (2 created / 1K connections)
[!!] Table cache hit rate: 1% (64 open / 4K opened)
[OK] Open file limit used: 8% (88/1K)
[OK] Table locks acquired immediately: 100% (1K immediate / 1K locks)
[!!] InnoDB data size / buffer pool: 967.7M/8.0M
-------- Recommendations -----------------------------------------------------
General recommendations:
Run OPTIMIZE TABLE to defragment tables for better performance
Enable the slow query log to troubleshoot bad queries
Increase table_cache gradually to avoid file descriptor limits
Variables to adjust:
table_cache (> 64)
innodb_buffer_pool_size (>= 967M)
UPDATE 1 :
Ao testar as consultas listadas aqui, geralmente não ocorre mais do que uma outra consulta e, normalmente, nenhuma.
Como a produção está lidando com pedidos do apache que o desenvolvimento obtém muito poucos, já que só eu e mais 1 pessoa o acessa - os 4GB de RAM poderiam esgotar usando a máquina única para o servidor apache e mysql?
Produção:
sudo hdparm -tT /dev/sda
/dev/sda:
Timing cached reads: 24872 MB in 2.00 seconds = 12450.72 MB/sec
Timing buffered disk reads: 368 MB in 3.00 seconds = 122.49 MB/sec
sudo hdparm -tT /dev/sdb
/dev/sdb:
Timing cached reads: 24786 MB in 2.00 seconds = 12407.22 MB/sec
Timing buffered disk reads: 350 MB in 3.00 seconds = 116.53 MB/sec
Server version(mysql + ubuntu versions): 5.1.61-0ubuntu0.10.04.1
Desenvolvimento:
sudo hdparm -tT /dev/sda
/dev/sda:
Timing cached reads: 10632 MB in 2.00 seconds = 5319.40 MB/sec
Timing buffered disk reads: 400 MB in 3.01 seconds = 132.85 MB/sec
Server version(mysql + ubuntu versions): 5.1.62-0ubuntu0.11.10.1
DADOS ORIGINAIS:
Esta consulta NÃO é a consulta em questão, mas está relacionada, portanto, mal colocada.
SELECT
f.form_question_has_answer_id
FROM
form_question_has_answer f
INNER JOIN
project_company_has_user p ON f.form_question_has_answer_user_id = p.project_company_has_user_user_id
INNER JOIN
company c ON p.project_company_has_user_company_id = c.company_id
INNER JOIN
project p2 ON p.project_company_has_user_project_id = p2.project_id
INNER JOIN
user u ON p.project_company_has_user_user_id = u.user_id
INNER JOIN
form f2 ON p.project_company_has_user_project_id = f2.form_project_id
WHERE
(f2.form_template_name = 'custom' AND p.project_company_has_user_garbage_collection = 0 AND p.project_company_has_user_project_id = '29') AND (LCASE(c.company_country) LIKE '%ge%' OR LCASE(c.company_country) LIKE '%abcde%') AND f.form_question_has_answer_form_id = '174'
E o plano de explicação para a consulta acima é, executado no dev e na produção, produzindo o mesmo plano.
+----+-------------+-------+--------+----------------------------------------------------------------------------------------------------------------------------------------------+----------------------------------+---------+----------------------------------------------------+------+-------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+-------------+-------+--------+----------------------------------------------------------------------------------------------------------------------------------------------+----------------------------------+---------+----------------------------------------------------+------+-------------+
| 1 | SIMPLE | p2 | const | PRIMARY | PRIMARY | 4 | const | 1 | Using index |
| 1 | SIMPLE | f | ref | form_question_has_answer_form_id,form_question_has_answer_user_id | form_question_has_answer_form_id | 4 | const | 796 | Using where |
| 1 | SIMPLE | u | eq_ref | PRIMARY | PRIMARY | 4 | new_klarents.f.form_question_has_answer_user_id | 1 | Using index |
| 1 | SIMPLE | p | ref | project_company_has_user_unique_key,project_company_has_user_user_id,project_company_has_user_company_id,project_company_has_user_project_id | project_company_has_user_user_id | 4 | new_klarents.f.form_question_has_answer_user_id | 1 | Using where |
| 1 | SIMPLE | f2 | ref | form_project_id | form_project_id | 4 | const | 15 | Using where |
| 1 | SIMPLE | c | eq_ref | PRIMARY | PRIMARY | 4 | new_klarents.p.project_company_has_user_company_id | 1 | Using where |
+----+-------------+-------+--------+----------------------------------------------------------------------------------------------------------------------------------------------+----------------------------------+---------+----------------------------------------------------+------+-------------+
Essa consulta leva de 2 a 20 segundos para ser executada.
A consulta que está sendo executada ATUALMENTE no servidor é esta:
SELECT
COUNT(*) AS num_results
FROM (SELECT
f.form_question_has_answer_id
FROM
form_question_has_answer f
INNER JOIN
project_company_has_user p ON f.form_question_has_answer_user_id = p.project_company_has_user_user_id
INNER JOIN
company c ON p.project_company_has_user_company_id = c.company_id
INNER JOIN
project p2 ON p.project_company_has_user_project_id = p2.project_id
INNER JOIN
user u ON p.project_company_has_user_user_id = u.user_id
INNER JOIN
form f2 ON p.project_company_has_user_project_id = f2.form_project_id
WHERE
(f2.form_template_name = 'custom' AND p.project_company_has_user_garbage_collection = 0 AND p.project_company_has_user_project_id = '29') AND (LCASE(c.company_country) LIKE '%ge%' OR LCASE(c.company_country) LIKE '%abcde%') AND f.form_question_has_answer_form_id = '174'
GROUP BY
f.form_question_has_answer_id;) dctrn_count_query;
Com planos de explicação (novamente, mesmo no dev e produção):
+----+-------------+-------+--------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------------------------+---------+----------------------------------------------------+------+------------------------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+-------------+-------+--------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------------------------+---------+----------------------------------------------------+------+------------------------------+
| 1 | PRIMARY | NULL | NULL | NULL | NULL | NULL | NULL | NULL | Select tables optimized away |
| 2 | DERIVED | p2 | const | PRIMARY | PRIMARY | 4 | | 1 | Using index |
| 2 | DERIVED | f | ref | form_question_has_answer_form_id,form_question_has_answer_user_id | form_question_has_answer_form_id | 4 | | 797 | Using where |
| 2 | DERIVED | p | ref | project_company_has_user_unique_key,project_company_has_user_user_id,project_company_has_user_company_id,project_company_has_user_project_id,project_company_has_user_garbage_collection | project_company_has_user_user_id | 4 | new_klarents.f.form_question_has_answer_user_id | 1 | Using where |
| 2 | DERIVED | f2 | ref | form_project_id | form_project_id | 4 | | 15 | Using where |
| 2 | DERIVED | c | eq_ref | PRIMARY | PRIMARY | 4 | new_klarents.p.project_company_has_user_company_id | 1 | Using where |
| 2 | DERIVED | u | eq_ref | PRIMARY | PRIMARY | 4 | new_klarents.p.project_company_has_user_user_id | 1 | Using where; Using index |
+----+-------------+-------+--------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------------------------+---------+----------------------------------------------------+------+------------------------------+
No servidor de produção, as informações que tenho são as seguintes.
Após a execução:
+-------------+
| num_results |
+-------------+
| 3 |
+-------------+
1 row in set (2 min 14.28 sec)
Mostrar perfil:
+--------------------------------+------------+
| Status | Duration |
+--------------------------------+------------+
| starting | 0.000016 |
| checking query cache for query | 0.000057 |
| Opening tables | 0.004388 |
| System lock | 0.000003 |
| Table lock | 0.000036 |
| init | 0.000030 |
| optimizing | 0.000016 |
| statistics | 0.000111 |
| preparing | 0.000022 |
| executing | 0.000004 |
| Sorting result | 0.000002 |
| Sending data | 136.213836 |
| end | 0.000007 |
| query end | 0.000002 |
| freeing items | 0.004273 |
| storing result in query cache | 0.000010 |
| logging slow query | 0.000001 |
| logging slow query | 0.000002 |
| cleaning up | 0.000002 |
+--------------------------------+------------+
No desenvolvimento, os resultados são os seguintes.
+-------------+
| num_results |
+-------------+
| 3 |
+-------------+
1 row in set (0.08 sec)
Novamente o perfil para esta consulta:
+--------------------------------+----------+
| Status | Duration |
+--------------------------------+----------+
| starting | 0.000022 |
| checking query cache for query | 0.000148 |
| Opening tables | 0.000025 |
| System lock | 0.000008 |
| Table lock | 0.000101 |
| optimizing | 0.000035 |
| statistics | 0.001019 |
| preparing | 0.000047 |
| executing | 0.000008 |
| Sorting result | 0.000005 |
| Sending data | 0.086565 |
| init | 0.000015 |
| optimizing | 0.000006 |
| executing | 0.000020 |
| end | 0.000004 |
| query end | 0.000004 |
| freeing items | 0.000028 |
| storing result in query cache | 0.000005 |
| removing tmp table | 0.000008 |
| closing tables | 0.000008 |
| logging slow query | 0.000002 |
| cleaning up | 0.000005 |
+--------------------------------+----------+
Se eu remover as juntas internas do usuário e / ou do projeto, a consulta será reduzida para 30s.
Última informação que tenho:
Mysqlserver e Apache estão na mesma caixa, há apenas uma caixa para produção.
Saída de produção do topo: antes de & depois.
top - 15:43:25 up 78 days, 12:11, 4 users, load average: 1.42, 0.99, 0.78
Tasks: 162 total, 2 running, 160 sleeping, 0 stopped, 0 zombie
Cpu(s): 0.1%us, 50.4%sy, 0.0%ni, 49.5%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 4037868k total, 3772580k used, 265288k free, 243704k buffers
Swap: 3905528k total, 265384k used, 3640144k free, 1207944k cached
top - 15:44:31 up 78 days, 12:13, 4 users, load average: 1.94, 1.23, 0.87
Tasks: 160 total, 2 running, 157 sleeping, 0 stopped, 1 zombie
Cpu(s): 0.2%us, 50.6%sy, 0.0%ni, 49.3%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 4037868k total, 3834300k used, 203568k free, 243736k buffers
Swap: 3905528k total, 265384k used, 3640144k free, 1207804k cached
Mas esta não é uma boa representação do status normal da produção, então aqui está uma amostra dela a partir de hoje, fora da execução das consultas.
top - 11:04:58 up 79 days, 7:33, 4 users, load average: 0.39, 0.58, 0.76
Tasks: 156 total, 1 running, 155 sleeping, 0 stopped, 0 zombie
Cpu(s): 3.3%us, 2.8%sy, 0.0%ni, 93.9%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 4037868k total, 3676136k used, 361732k free, 271480k buffers
Swap: 3905528k total, 268736k used, 3636792k free, 1063432k cached
Desenvolvimento: Este não muda durante ou depois.
top - 15:47:07 up 110 days, 22:11, 7 users, load average: 0.17, 0.07, 0.06
Tasks: 210 total, 2 running, 208 sleeping, 0 stopped, 0 zombie
Cpu(s): 0.1%us, 0.2%sy, 0.0%ni, 99.7%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 4111972k total, 1821100k used, 2290872k free, 238860k buffers
Swap: 4183036k total, 66472k used, 4116564k free, 921072k cached