Use pg_memory_is_all_zeros() in pgstatfuncs.c.

There are a few places in this file that use memset() and memcmp()
to determine whether a section of memory is all zeros.  This commit
modifies them to use pg_memory_is_all_zeros() instead.  These
aren't expected to be hot code paths, but this may optimize them a
bit.  Plus, this allows us to remove some variables that were only
needed for the memset() and memcmp().

Author: Bertrand Drouvot
Reviewed-by: Michael Paquier
Discussion: https://postgr.es/m/Z1hNubHfvMxlW6eu%40ip-10-97-1-34.eu-west-3.compute.internal

diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index 60a397dc56120fd60eafb35c1f04343815dc2bf9..cdf37403e9d521793d1a60e05ec21214c5537c45 100644 (file)
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -361,7 +361,6 @@ pg_stat_get_activity(PG_FUNCTION_ARGS)
        /* Values only available to role member or pg_read_all_stats */
        if (HAS_PGSTAT_PERMISSIONS(beentry->st_userid))
        {
-           SockAddr    zero_clientaddr;
            char       *clipped_activity;
 
            switch (beentry->st_state)
@@ -483,9 +482,8 @@ pg_stat_get_activity(PG_FUNCTION_ARGS)
                nulls[11] = true;
 
            /* A zeroed client addr means we don't know */
-           memset(&zero_clientaddr, 0, sizeof(zero_clientaddr));
-           if (memcmp(&(beentry->st_clientaddr), &zero_clientaddr,
-                      sizeof(zero_clientaddr)) == 0)
+           if (pg_memory_is_all_zeros(&beentry->st_clientaddr,
+                                      sizeof(beentry->st_clientaddr)))
            {
                nulls[12] = true;
                nulls[13] = true;
@@ -880,7 +878,6 @@ pg_stat_get_backend_client_addr(PG_FUNCTION_ARGS)
 {
    int32       procNumber = PG_GETARG_INT32(0);
    PgBackendStatus *beentry;
-   SockAddr    zero_clientaddr;
    char        remote_host[NI_MAXHOST];
    int         ret;
 
@@ -891,9 +888,8 @@ pg_stat_get_backend_client_addr(PG_FUNCTION_ARGS)
        PG_RETURN_NULL();
 
    /* A zeroed client addr means we don't know */
-   memset(&zero_clientaddr, 0, sizeof(zero_clientaddr));
-   if (memcmp(&(beentry->st_clientaddr), &zero_clientaddr,
-              sizeof(zero_clientaddr)) == 0)
+   if (pg_memory_is_all_zeros(&beentry->st_clientaddr,
+                              sizeof(beentry->st_clientaddr)))
        PG_RETURN_NULL();
 
    switch (beentry->st_clientaddr.addr.ss_family)
@@ -925,7 +921,6 @@ pg_stat_get_backend_client_port(PG_FUNCTION_ARGS)
 {
    int32       procNumber = PG_GETARG_INT32(0);
    PgBackendStatus *beentry;
-   SockAddr    zero_clientaddr;
    char        remote_port[NI_MAXSERV];
    int         ret;
 
@@ -936,9 +931,8 @@ pg_stat_get_backend_client_port(PG_FUNCTION_ARGS)
        PG_RETURN_NULL();
 
    /* A zeroed client addr means we don't know */
-   memset(&zero_clientaddr, 0, sizeof(zero_clientaddr));
-   if (memcmp(&(beentry->st_clientaddr), &zero_clientaddr,
-              sizeof(zero_clientaddr)) == 0)
+   if (pg_memory_is_all_zeros(&beentry->st_clientaddr,
+                              sizeof(beentry->st_clientaddr)))
        PG_RETURN_NULL();
 
    switch (beentry->st_clientaddr.addr.ss_family)