i was configuring ubuntu to use postgresql ,i got this error,
* Restarting PostgreSQL 8.3 database server * The PostgreSQL server failed to start. Please check the log output:
2009-04-23 16:13:10 EST LOG: could not load root certificate file "root.crt": no SSL error reported
2009-04-23 16:13:10 EST DETAIL: Will not verify client certificates.
2009-04-23 16:13:10 EST FATAL: could not create shared memory segment: Invalid argument
2009-04-23 16:13:10 EST DETAIL: Failed system call was shmget(key=5432001, size=140181504, 03600).
2009-04-23 16:13:10 EST HINT: This error usually means that PostgreSQL's request for a shared memory segment exceeded your kernel's SHMMAX parameter. You can either reduce the request size or reconfigure the kernel with larger SHMMAX. To reduce the request size (currently 140181504 bytes), reduce PostgreSQL's shared_buffers parameter (currently 16384) and/or its max_connections parameter (currently 103).
If the request size is already small, it's possible that it is less than your kernel's SHMMIN parameter, in which case raising the request size or reconfiguring SHMMIN is called for.
The PostgreSQL documentation contains more information about shared memory configuration.