Say I have some highly-visited front-page, which displays number of some items by categories. When some item is added / deleted I need to invalidate this front-page/url and some 2 others. What is the best practice how to invalidate those urls from backend in Varnish (4.x)? From what I captured, I can: implement my HTTP PURGE handler in VCL configuration file, that "bans" urls matching received regex from backend to Varnish, send 3x HTTP PURGE requests for those 3 urls. But is this approach safe for this automatic usage? Basicly I need to invalidate some views everytime some related entity is inserted/updated/deleted. Can it lead to ban list cumulation and increasing CPU consumption? Is there any other approach? Thanks.