Entries Written By Jervin R
Cacti Graphs for Apache Not Working? Check Your IPv6
I was wondering earlier why my Apache Cacti graphs were all graphing 0s. Looking to test manually, I see it’s either 0s or -1s like below.
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; html-script: false ][revin@forge ~]# /usr/bin/php -q /usr/share/cacti/scripts/ss_get_by_ssh.php --host xx.xx.xxx.xxx --type apache --items g1,g3 g1:-1 g3:-1 |
Looking at the Apache access log on the target server, I noticed Cacti was trying to connect to the IPv6 loopback address “::1”.
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; html-script: false ]::1 - - [13/Oct/2012:22:00:02 -0400] "GET /server-status?auto HTTP/1.0" 403 290 "-" "Cacti/1.0" |
Fortunately this was easy …
Apache Running on Multiple Ports and Percona Cacti Templates for Apache
For some users, running Apache on different ports is more economical than adding multiple IPs to the same server i.e. when you have several Apache servers behind a load balancer where the public IP is in front of the load balancer. If you’re thinking of using the Percona Monitoring Templates for Cacti particularly for Apache, …
Optimizing OR’ed WHERE Clauses Between JOIN’ed Tables
OR conditions are normally difficult to optimize when used on different columns, a pain when the columns are of range conditions and worst when done between 2 or more different tables. Look at my example below, the original query is trying to find rows which conditions are based on columns from the JOIN’ed tables.
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mysql [localhost] {msandbox} (employees) > EXPLAIN SELECT -> e.emp_no, birth_date, first_name, -> last_name, gender, hire_date, -> salary, from_date, to_date -> FROM employees e -> INNER JOIN salaries s ON (e.emp_no = s.emp_no) -> WHERE e.hire_date BETWEEN '1990-06-01 00:00:00' AND '1990-07-01 00:00:00' OR -> s.from_date BETWEEN '1990-06-01 00:00:00' AND '1990-07-01 00:00:00' -> ORDER BY e.emp_no, hire_date, from_date \G *************************** 1. row *************************** id: 1 select_type: SIMPLE table: e type: ALL possible_keys: PRIMARY,hire_date key: NULL key_len: NULL ref: NULL rows: 300547 Extra: Using temporary; Using filesort *************************** 2. row *************************** id: 1 select_type: SIMPLE table: s type: ref possible_keys: PRIMARY,emp_no,from_date key: PRIMARY key_len: 4 ref: employees.e.emp_no rows: 4 Extra: Using where 2 rows in set (0.00 sec) mysql [localhost] {msandbox} (employees) > SHOW CREATE TABLE employees \G *************************** 1. row *************************** Table: employees Create Table: CREATE TABLE `employees` ( `emp_no` int(11) NOT NULL, `birth_date` date NOT NULL, `first_name` varchar(14) NOT NULL, `last_name` varchar(16) NOT NULL, `gender` enum('M','F') NOT NULL, `hire_date` date NOT NULL, PRIMARY KEY (`emp_no`), KEY `hire_date` (`hire_date`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 1 row in set (0.00 sec) mysql [localhost] {msandbox} (employees) > SHOW CREATE TABLE salaries \G *************************** 1. row *************************** Table: salaries Create Table: CREATE TABLE `salaries` ( `emp_no` int(11) NOT NULL, `salary` int(11) NOT NULL, `from_date` date NOT NULL, `to_date` date NOT NULL, PRIMARY KEY (`emp_no`,`from_date`), KEY `emp_no` (`emp_no`), KEY `from_date` (`from_date`), CONSTRAINT `salaries_ibfk_1` FOREIGN KEY (`emp_no`) REFERENCES `employees` (`emp_no`) ON DELETE CASCADE ) ENGINE=InnoDB DEFAULT CHARSET=latin1 1 row in set (0.00 sec) |
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