MYSQL View Slowed Down - mysql

Question

I have a mysql view that slowed down when the database it was interpreting became overloaded due to a programming flaw. I fixed that flaw and cleared the database back down to a very small size.
I have a database with identical tables and identical data on the same host/server. It has the same view. The query for that view finishes well under 1sec, but the query of the problem view takes 20+sec.
Is there a cache or something else that I may need to clear to fix this?
select
`income`.`id` AS `id`
from
(`clientsWithIncome`
left join `income` ON (`income`.`client` = `clientsWithIncome`.`client`))
The above is the most simplified form of the query that gives me the problem. I can perform this on one database and get results in under one second, and then on the problem database it takes 20 seconds.
delimiter $$
CREATE TABLE `income` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`index` varchar(45) DEFAULT NULL,
`client` varchar(45) DEFAULT NULL,
`entity_type` varchar(45) DEFAULT NULL,
`date_received` varchar(45) DEFAULT NULL,
`preparer` varchar(45) DEFAULT NULL,
`date_began` varchar(45) DEFAULT NULL,
`date_prepared` varchar(45) DEFAULT NULL,
`date_assembled` varchar(45) DEFAULT NULL,
`date_signed` varchar(45) DEFAULT NULL,
`date_fed` varchar(45) DEFAULT NULL,
`date_state` varchar(45) DEFAULT NULL,
`notes` text,
`status` varchar(45) DEFAULT NULL,
`year` varchar(45) DEFAULT NULL,
`highlight` varchar(45) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=MyISAM AUTO_INCREMENT=93442 DEFAULT CHARSET=latin1$$
And the VIEWs:
delimiter $$
CREATE ALGORITHM=UNDEFINED DEFINER=`xxxxxxxxxxx`#`localhost`
SQL SECURITY DEFINER VIEW `clientsWithIncome` AS
select `income`.`client` AS `client`
from `income`
where (`income`.`year` = (year((curdate() + interval 1 month)) - 1))
union
select `contacts`.`client` AS `client`
from `contacts`
where (`contacts`.`tax_returns` = 1)$$
delimiter $$
CREATE ALGORITHM=UNDEFINED DEFINER=`xxxxxxxxxxxx`#`localhost`
SQL SECURITY DEFINER VIEW `currentIncome` AS
select `income`.`id` AS `id`,
`income`.`index` AS `index`,
`clientsWithIncome`.`client` AS `client`,
`income`.`entity_type` AS `entity_type`,
`income`.`date_received` AS `date_received`,
`income`.`preparer` AS `preparer`,
`income`.`date_began` AS `date_began`,
`income`.`date_prepared` AS `date_prepared`,
`income`.`date_assembled` AS `date_assembled`,
`income`.`date_signed` AS `date_signed`,`income`.`date_fed` AS `date_fed`,
`income`.`date_state` AS `date_state`,`income`.`notes` AS `notes`,
`income`.`status` AS `status`,`income`.`year` AS `year`,
`income`.`highlight` AS `highlight`
from (`clientsWithIncome`
left join `income`
on(((`income`.`client` = `clientsWithIncome`.`client`)
and (`income`.`year` = (year((curdate() + interval 1 month)) - 1))))
)$$

Answer 1

My answer turned out to be what I thought it was. Some sort of caching.
I performed the following from PHPmyAdmin:
Check table
Repair table
Optimize table
Flush table
Now the queries are performing wonderfully.

Answer 2

year varchar(45) DEFAULT NULL,
There is a YEAR datatype; use it.
Add INDEX(year)
Add INDEX(client)
Add INDEX(tax_returns)
If those suggestions don't help enough, come back with...
Please provide SHOW CREATE TABLE for the other table.
Please provide EXPLAIN SELECT ...
Use NOT NULL on columns that you will always set.