From: James Turner <zakalawe@mac.com>
Date: Sat, 19 Jan 2013 13:58:22 +0000 (+0000)
Subject: Increase the nav-cache in-memory cache size.
X-Git-Url: https://git.mxchange.org/?a=commitdiff_plain;h=a138952ee5ea02976d54924d74f2c370c5596c4b;p=flightgear.git

Increase the nav-cache in-memory cache size.

(Avoid thrash in certain cases)
---

diff --git a/src/Navaids/NavDataCache.cxx b/src/Navaids/NavDataCache.cxx
index a79778c70..0a09c3187 100644
--- a/src/Navaids/NavDataCache.cxx
+++ b/src/Navaids/NavDataCache.cxx
@@ -72,7 +72,8 @@ namespace {
 
 const int MAX_RETRIES = 10;
 const int SCHEMA_VERSION = 6;
-
+const int CACHE_SIZE_KBYTES= 16000;
+    
 // bind a std::string to a sqlite statement. The std::string must live the
 // entire duration of the statement execution - do not pass a temporary
 // std::string, or the compiler may delete it, freeing the C-string storage,
@@ -248,6 +249,11 @@ public:
       }
     }
     
+    // see http://www.sqlite.org/pragma.html#pragma_cache_size
+    // for the details, small cache would cause thrashing.
+    std::ostringstream q;
+    q << "PRAGMA cache_size=-" << CACHE_SIZE_KBYTES << ";";
+    runSQL(q.str());
     prepareQueries();
   }