Mercurial > hg > orthanc-postgresql

changeset 10:401684ea8d73

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Use of advisory locks
author Sebastien Jodogne <s.jodogne@gmail.com>
date Fri, 27 Feb 2015 16:56:00 +0100
parents c074a7321bad
children 1efb30985931
files Core/GlobalProperties.cpp Core/PostgreSQLResult.cpp Core/PostgreSQLResult.h NEWS
diffstat 4 files changed, 39 insertions(+), 2 deletions(-) [+]
line wrap: on
line diff
--- a/Core/GlobalProperties.cpp	Mon Feb 16 09:46:54 2015 +0100
+++ b/Core/GlobalProperties.cpp	Fri Feb 27 16:56:00 2015 +0100
@@ -25,6 +25,8 @@
 #include "PostgreSQLResult.h"
 #include "PostgreSQLTransaction.h"
 
+#define USE_ADVISORY_LOCK  1
+
 namespace OrthancPlugins
 {
   GlobalProperties::GlobalProperties(PostgreSQLConnection& connection,
@@ -53,6 +55,20 @@
     {
       PostgreSQLTransaction transaction(connection_);
 
+#if USE_ADVISORY_LOCK == 1
+      PostgreSQLStatement s(connection_, "select pg_try_advisory_lock($1);");
+      s.DeclareInputInteger(0);
+      s.BindInteger(0, lockKey_);
+
+      PostgreSQLResult result(s);
+      if (result.IsDone() ||
+          !result.GetBoolean(0))
+      {
+        throw PostgreSQLException("The database is locked by another instance of Orthanc.");
+      }
+#else
+      PostgreSQLTransaction transaction(connection_);
+
       // Check the lock
       if (!allowUnlock)
       {
@@ -67,6 +83,7 @@
 
       // Lock the database
       SetGlobalProperty(lockKey_, "1");             
+#endif
 
       transaction.Commit();
     }
@@ -130,10 +147,14 @@
   {
     if (useLock_)
     {
+#if USE_ADVISORY_LOCK == 1
+      // Nothing to do, the lock is released after the connection is closed
+#else
       // Remove the lock
       PostgreSQLTransaction transaction(connection_);
       SetGlobalProperty(lockKey_, "0");
       transaction.Commit();
+#endif
     }
   }
 }
--- a/Core/PostgreSQLResult.cpp	Mon Feb 16 09:46:54 2015 +0100
+++ b/Core/PostgreSQLResult.cpp	Fri Feb 27 16:56:00 2015 +0100
@@ -98,6 +98,14 @@
     return PQgetisnull(reinterpret_cast<PGresult*>(result_), position_, column) != 0;
   }
 
+  bool PostgreSQLResult::GetBoolean(unsigned int column) const
+  {
+    CheckColumn(column, BOOLOID);
+    assert(PQfsize(reinterpret_cast<PGresult*>(result_), column) == 1);
+    const uint8_t *v = reinterpret_cast<const uint8_t*>(PQgetvalue(reinterpret_cast<PGresult*>(result_), position_, column));
+    return (v[0] != 0);
+  }
+
   int PostgreSQLResult::GetInteger(unsigned int column) const
   {
     CheckColumn(column, INT4OID);
--- a/Core/PostgreSQLResult.h	Mon Feb 16 09:46:54 2015 +0100
+++ b/Core/PostgreSQLResult.h	Fri Feb 27 16:56:00 2015 +0100
@@ -54,6 +54,8 @@
 
     bool IsNull(unsigned int column) const;
 
+    bool GetBoolean(unsigned int column) const;
+
     int GetInteger(unsigned int column) const;
 
     int64_t GetInteger64(unsigned int column) const;
--- a/NEWS	Mon Feb 16 09:46:54 2015 +0100
+++ b/NEWS	Fri Feb 27 16:56:00 2015 +0100
@@ -1,4 +1,10 @@
-Version 1.0.0 (2015/02/06)
-==========================
+Pending changes in the mainline
+===============================
+
+* Use of advisory locks
+
+
+2015/02/06
+==========
 
 * Initial release