From 6045c90bf00c8c1fe22df783e5ba36ecd4834a77 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Markus=20M=C3=A4kel=C3=A4?= <markus.makela@mariadb.com>
Date: Wed, 17 Oct 2018 10:15:14 +0300
Subject: [PATCH] Log query classifier cache size on startup

---
 server/core/config.cc | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/server/core/config.cc b/server/core/config.cc
index 305fb7161..06a6538d3 100644
--- a/server/core/config.cc
+++ b/server/core/config.cc
@@ -1224,6 +1224,29 @@ bool config_load_global(const char* filename)
                             "cache. Manually define `%s` to enable it.",
                             CN_QUERY_CLASSIFIER_CACHE_SIZE);
             }
+            else
+            {
+                std::vector<const char*> suffixes
+                {
+                    "B",
+                    "KiB",
+                    "MiB",
+                    "GiB",
+                    "TiB",
+                    "PiB",
+                    "EiB",
+                    "ZiB",
+                    "YiB"
+                };
+                // Get the total used cache memory
+                int64_t total_mem = mem_per_thr * gateway.n_threads;
+                // Calculate log1024(total_mem) and round it up
+                double c = ceil(log(total_mem) / log(1024));
+                // In case someone still uses MaxScale in the year 3054
+                int idx = std::min(c, (double)(suffixes.size())) - 1;
+                double num = total_mem / pow(1024, idx);
+                MXS_NOTICE("Using up to %.2lf%s of memory for query classifier cache", num, suffixes[idx]);
+            }
         }
     }