Re: 2 hours to compile mysql?

[Michael Widenius]

>>>>> "Leif" == Leif Neland <leif@stripped> writes:

>> The reason for this is that some gcc optimizations stages takes
>> exponentially more memory when compiling big functions.
>> bison produces one big function for the grammar parsing and its
>> this that takes a long time to compile;  To compile sql_yacc.cc quickly
>> on Intel, you nead at least 160M of free ram.  On a PentiumII 400mz with 256M
>> ram, it takes 11 seconds to compile sql_yacc.o.  Having to use swap
>> can easily make things 1000 times slower
>> 

Leif> Is amount of ram available (portably) to configure?

I don't think thats easy to check for..

Aother problem is also that even if you have only little ram, you
may still want to compile MySQL without --low-memory, because the
final code is much better if you don't have to use --low-memory.

Leif> So configure could decide to use --low-memory by itself? Allowing
Leif> overrides, naturally.

Leif> Leif

Regards,
Monty