[Info-vax] Oracle on VMS

[Arne Vajhøj]

On 11/20/2016 4:04 AM, Jan-Erik Soderholm wrote:
> Den 2016-11-20 kl. 07:01, skrev IanD:
>> Yes, modern DB's do cache execution plans, RDB I believe was the first
>> to come up with the idea of a query optimizer and unlike MySQL (or how
>> it used to be) with RDB you can access the query optimiser for free and
>> it's cincluded in the price and even make changes to it to force your
>> own behavior if you believe the DB got it wrong on it's strategy
>> (usually happens when it gets the number of tuples wrong on complex
>> joins etc)
>>
>> I wonder with the push for dynamic languages how much optimisation is
>> worth it at compile time versus having a smarter optimiser at run time?
>
> With dynamic SQL (where the SQL is sent in plain text to the DB each time)
> the DB has to do syntaxt check each time an SQL is executed.

No. If the execution plan is cached with SQL as key, then there is no
need to check the syntax.

Arne