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) */