I see wordpress database on wp_posts table, you will find 2 posts to keep publish date, post_date and post_date_gmt

post_date_gmt keep publish date in GMT time. And post_date store publish date in user time who produce the publish. Shall We Be Held right?

Can there be any help to store both version of publish date on database?

Could it be faster to keep both version of publish date instead of calculate post_date_gmt with user timezone when user wish to view publish date according to his/her timezone

UPDATE: I Additionally request on-site point and obtain this answer

The main one benefit it might provide is when the individual moves to some different timezone then their earlier posts still record what time that it was where these were once they published them and never what time that it was where they are actually (as could be whatever you could calculate while using GMT some time and their current timezone).

http://www.sitepoint.com/forums/showthread.php?p=4671837

Unsure concerning the speed around the interpreter. One large reason they will use GMT is really it helps make the date-time more portable and never associated with a particular timezone and enables you to definitely write code that's more general and internationalized. Why they save both is curious however the GMT format is certainly preferred for database storage.