[sqlite] cache_size documentation vs. page_size setting

[Andrew Finkenstadt]

In the documentation for cache_size, the description for how much memory a
page takes up says "Each page uses about 1.5K of memory.".  I believe that
it is more accurate to say that "Each page uses the database page_size plus
about 512 bytes."  I don't know how best to phrase it, save as a series of
examples.

"When the page_size is 1K (the default value), each cache page uses about
1.5K.  When the page_size is 32K (the largest possible value), each cache
page uses about 32.5K."

from pagerAllocatePage(...):

   pPg = sqliteMallocRaw( sizeof(*pPg) + pPager->pageSize
                           + sizeof(u32) + pPager->nExtra
                           + MEMDB*sizeof(PgHistory) );

Best,
andy