Add memory info to getrusage output

Add the maxrss field to the getrusage output (log_*_stats).  This was
previously omitted because of portability concerns, but we feel this
might not be a concern anymore.

based on patch by Justin Pryzby <[email protected]>

diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index b8d860ebdbf42ebc60cc19c8bffba48007ceeab5..8d3fecf6d6abb28d894f13a1a983f95a95edd5a9 100644 (file)
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -4421,11 +4421,8 @@ ShowUsage(const char *title)
    }
 
    /*
-    * the only stats we don't show here are for memory usage -- i can't
-    * figure out how to interpret the relevant fields in the rusage struct,
-    * and they change names across o/s platforms, anyway. if you can figure
-    * out what the entries mean, you can somehow extract resident set size,
-    * shared text size, and unshared data and stack sizes.
+    * The only stats we don't show here are ixrss, idrss, isrss.  It takes
+    * some work to interpret them, and most platforms don't fill them in.
     */
    initStringInfo(&str);
 
@@ -4445,6 +4442,16 @@ ShowUsage(const char *title)
                     (long) sys.tv_sec,
                     (long) sys.tv_usec);
 #if defined(HAVE_GETRUSAGE)
+   appendStringInfo(&str,
+                    "!\t%ld kB max resident size\n",
+#if defined(__darwin__)
+                    /* in bytes on macOS */
+                    r.ru_maxrss/1024
+#else
+                    /* in kilobytes on most other platforms */
+                    r.ru_maxrss
+#endif
+       );
    appendStringInfo(&str,
                     "!\t%ld/%ld [%ld/%ld] filesystem blocks in/out\n",
                     r.ru_inblock - Save_r.ru_inblock,