PAE, revisited

So, I read this thread, and I’m still a bit mystified. So for the purposes of demystifying, even if one has PAE kernel, one should act as if one has 4GB available. To wit, these settings:
key_buffer_size = 384Minnodb_buffer_pool_size = 2048Minnodb_additional_mem_pool_size = 128M# take the defaults for now# myisam_sort_buffer_size# sort_buffer_size # read_buffer_size # read_rnd_buffer_size # join_buffer_size#I don’t know if these are included in the memory footprinttmp_table_size = 1024Mmax_heap_table_size = 1024M
Cause error messages like this:
080226 13:01:13 InnoDB: Started; log sequence number 0 46604/usr/sbin/mysqld: Out of memory (Needed 357273600 bytes)/usr/sbin/mysqld: Out of memory (Needed 267955200 bytes)/usr/sbin/mysqld: Out of memory (Needed 200964096 bytes)/usr/sbin/mysqld: Out of memory (Needed 150721536 bytes)
If I knock the innodb buffer pool to 1280M starts fine.

In case you’re wondering, the MIQ (machine in question) can do 64-bit, but company politics are forcing situation that makes 32-bit OS necessary.


I actually meant to ask a question. The World Wide Interwebs are conspicuously silent about PAE and mysql. So, does anyone else agree that even when using PAE (implying 32-bit OS), the mysql daemon is still limited to theoretical 4GB (2.8GB practical)?

My assumption was that PAE allowed any application access to as much available memory as the application requested. What seems to be the actual case is even though PAE makes the memory address space essentially 36 bit, the applications, e.g. mysql, are still 32 bit with 32 bit pointers and all some such. So the only thing PAE really gives you is the ability to run more applications not bigger applications.

There, I answered my own question, I think.

i think this link ( can help.