On 9/21/21 3:30 PM, Andres Freund wrote: > Hi, > > For the AIO stuff I needed to build postgres for windows. And I was a bit > horrified by the long compile times. At first I was ready to blame the MS > compiler for being slow, until I noticed that using mingw gcc from linux to > cross compile to windows is also a *lot* slower than building for linux. > > I found some blog-post-documented-only compiler flags [1], most importantly > /d1reportTime. Which shows that the include processing of postgres.h takes > 0.6s [2] > > Basically all the time in a debug windows build is spent parsing windows.h and > related headers. Argh. > > The amount of stuff we include in win32_port.h and declare is pretty absurd > imo. There's really no need to expose the whole backend to all of it. Most of > it should just be needed in a few port/ files and a few select users. > > But that's too much work for my taste. As it turns out there's a partial > solution to windows.h being just so damn big, the delightfully named > WIN32_LEAN_AND_MEAN. > > This reduces the non-incremental buildtime in my 8 core windows VM from 187s > to > 140s. Cross compiling from linux it's > master: > real 0m53.807s > user 22m16.930s > sys 2m50.264s > WIN32_LEAN_AND_MEAN > real 0m32.956s > user 12m17.773s > sys 1m52.313s
Nice! I also see references to VC_EXTRALEAN which defines this and some other stuff that might make things even faster. Worth investigating. cheers andrew -- Andrew Dunstan EDB: https://www.enterprisedb.com
