Hello! On Tue, May 30, 2017 at 03:28:03PM +0500, Andrew Borodin wrote:
> Hi, nginxers! > > We often use hashtable sizes equal to the power of 2. This can be > damaging for a hashtable. I haven't found any mitigation for this in > nginx code. So I made my own. If this issue is addressed somewhere > just ignore my message. Or I'd be happy if someone will point me it. > > For the explanation of problem see > https://stackoverflow.com/questions/3980117/hash-table-why-size-should-be-prime > > Code is checked for correctness of ngx_hash_min_prime(), I haven't > done any regression testing, sorry. The maximum size of hash table as specified by the hinit->max_size field is indeed maximum size, and not the size of the hash table. Following code in the ngx_hash_init() will try hard to find to find out an optimal hash size for a given set of values within the maximum size specified, and will test all the prime numbers as well. I see no reasons to additionally limit the maximum size to a prime number. If you think there are some, please be more specific. -- Maxim Dounin http://nginx.org/ _______________________________________________ nginx-devel mailing list nginx-devel@nginx.org http://mailman.nginx.org/mailman/listinfo/nginx-devel
