Thanks for your reply, and sorry for not verifying in the manual. Another
couple of questions I have :
If I run a EXPLAIN query and SELECT against a primary key and SELECT fields
which are not indexed, I assume that returned EXPLAIN statement as below,
means I don't need to index additional fields providing the PRIMARY KEY is
included in the SELECT statement ?
Also, if I want to add a index to an existing table containing 9000 records,
how long should I expect this to take ? Is it instant ?
On Thu, Jul 22, 2010 at 5:20 PM, Shawn Green (MySQL) <
> On 7/21/2010 1:02 PM, Tompkins Neil wrote:
>> So Just running a basic query I get returned the following :
>> Products,ALL,,,,,9884,where used,
>> Therefore, I assume "*ALL*" is the worst possible type and should look at
>> adding a an index to this particular field ?
> Why assume when the manual is right there to remove all doubt?
> A full table scan is done for each combination of rows from the previous
> tables. This is normally not good if the table is the first table not marked
> const, and usually very bad in all other cases. Normally, you can avoid ALL
> by adding indexes that enable row retrieval from the table based on constant
> values or column values from earlier tables.
> Shawn Green
> MySQL Principle Technical Support Engineer
> Oracle USA, Inc.
> Office: Blountville, TN