We use hsregex on older Solaris (2.0-2.5 or something like that).
Theoretically maybe something stops working or starts working when the switch
is made, but beyond that theoretical possibility does anyone have real
knowledge that there is a non-trivial likelihood of that occurring or that
actual problems have been seen when this was done?
I've dealt with a couple of severe performance problems with regular
expressions recently with a 1.3-based server on Solaris 8. There has been
ample opportunity to hear such reports on other platforms that use hsregex, yet
I haven't heard anything.
In one of the cases, I was able to compare the expensive expression match on
Solaris vs. AIX. The AIX build, using hsregex, had slight degradation (~10%),
whereas the Solaris build, using native regex support, consumed multiple times
the normal CPU.
In the current case, where it seems to loop forever in the regex code, I know
the AliasMatch expressions which are being evaluated but not what request
triggered it. (I should have had the customer enable ExtendedStatus and then
check the server-status entry for the high-cpu child before they had to kill it
:( ) The only AliasMatch directives look like this, one per vhost:
AliasMatch ^(/.+)+(/.+\.css)$ /foo1/foo2/foo3/css/$1/$2
Probably I will end up building them a server using hsregex and get them to see
if the problem reoccurs.
