From 5fde047f2b41e71706d4ea9e8eb0a401f64192c1 Mon Sep 17 00:00:00 2001 From: Andres Freund Date: Fri, 9 Nov 2018 20:43:56 -0800 Subject: [PATCH] Combine two flag tests in GetSnapshotData(). Previously the code checked PROC_IN_LOGICAL_DECODING and PROC_IN_VACUUM separately. As the relevant variable is marked as volatile, the compiler cannot combine the two tests. As GetSnapshotData() is pretty hot in a number of workloads, it's worthwhile to fix that. It'd also be a good idea to get rid of the volatiles altogether. But for one that's a larger patch, and for another, the code after this change still seems at least as easy to read as before. Author: Andres Freund Discussion: https://postgr.es/m/20181005172955.wyjb4fzcdzqtaxjq@alap3.anarazel.de --- src/backend/storage/ipc/procarray.c | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-) diff --git a/src/backend/storage/ipc/procarray.c b/src/backend/storage/ipc/procarray.c index 908f62d37e..c861f3e17f 100644 --- a/src/backend/storage/ipc/procarray.c +++ b/src/backend/storage/ipc/procarray.c @@ -1589,14 +1589,11 @@ GetSnapshotData(Snapshot snapshot) TransactionId xid; /* - * Backend is doing logical decoding which manages xmin - * separately, check below. + * Skip over backends doing logical decoding which manages xmin + * separately (check below) and ones running LAZY VACUUM. */ - if (pgxact->vacuumFlags & PROC_IN_LOGICAL_DECODING) - continue; - - /* Ignore procs running LAZY VACUUM */ - if (pgxact->vacuumFlags & PROC_IN_VACUUM) + if (pgxact->vacuumFlags & + (PROC_IN_LOGICAL_DECODING | PROC_IN_VACUUM)) continue; /* Update globalxmin to be the smallest valid xmin */