# When large page size is not desirable

On a system with limited memory or limited disk space, large database pages may not improve performance.

Large database pages reduce I/O time because Derby can access more data with fewer I/Os. However, large pages require more memory. Derby allocates a bulk number of database pages in its page cache by default. If the page size is large, the system might run out of memory.

Use the -Xmx flag as an optional parameter to the JVM to give the JVM more memory upon startup.

For example:

    java -Xmx64M myApp

If you have limited disk space and cannot afford the overhead of the minimum two pages per table, keep your page sizes small.

Parent topic: Performance trade-offs of large pages
Related concepts
When large page size does not improve performance