C comment: explain procArray->pgprocnos[]

Reported-by: Aleksander Alekseev
Discussion: https://postgr.es/m/CAJ7c6TOs9Dh3KNR2kiQJ3Ow0=TBucL_57DAbm--2p8w5x_8YXQ@mail.gmail.com

Author: Aleksander Alekseev

Backpatch-through: master

diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 91824b469180f836bb5e72bf74c590bd5e59f13b..ed874459b380db756a28fb8fb1efb13ba2b66ced 100644 (file)
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -193,7 +193,11 @@ struct PGPROC
 
    int         pgxactoff;      /* offset into various ProcGlobal->arrays with
                                 * data mirrored from this PGPROC */
-   int         pgprocno;
+
+   int         pgprocno;       /* Number of this PGPROC in
+                                * ProcGlobal->allProcs array. This is set
+                                * once by InitProcGlobal().
+                                * ProcGlobal->allProcs[n].pgprocno == n */
 
    /* These fields are zero while a backend is still starting up: */
    BackendId   backendId;      /* This backend's backend ID (if assigned) */