merging 5.1 -> 5.1 rpl. 3 of 4 conflicts are resolved similarly to 6.0->6.0-rpl merging.

mysql_upgrade results changed due to the error messesge of mysqlcheck has changed.

2 files changed, 31 insertions, 13 deletions

diff --git a/mysys/my_symlink.c b/mysys/my_symlink.c
index f8c6ebf02c3..258e227bb7b 100644
--- a/mysys/my_symlink.c
+++ b/mysys/my_symlink.c
@@ -90,16 +90,6 @@ int my_symlink(const char *content, const char *linkname, myf MyFlags)
 #endif /* HAVE_READLINK */
 }
 
-/*
-  Resolve all symbolic links in path
-  'to' may be equal to 'filename'
-
-  Because purify gives a lot of UMR errors when using realpath(),
-  this code is disabled when using purify.
-
-  If MY_RESOLVE_LINK is given, only do realpath if the file is a link.
-*/
-
 #if defined(SCO)
 #define BUFF_LEN 4097
 #elif defined(MAXPATHLEN)
@@ -124,10 +114,15 @@ int my_is_symlink(const char *filename __attribute__((unused)))
 }
 
 
+/*
+  Resolve all symbolic links in path
+  'to' may be equal to 'filename'
+*/
+
 int my_realpath(char *to, const char *filename,
 		myf MyFlags __attribute__((unused)))
 {
-#if defined(HAVE_REALPATH) && !defined(HAVE_purify) && !defined(HAVE_BROKEN_REALPATH)
+#if defined(HAVE_REALPATH) && !defined(HAVE_BROKEN_REALPATH)
   int result=0;
   char buff[BUFF_LEN];
   char *ptr;
diff --git a/mysys/thr_mutex.c b/mysys/thr_mutex.c
index 49003553f0b..8f9928026ba 100644
--- a/mysys/thr_mutex.c
+++ b/mysys/thr_mutex.c
@@ -438,9 +438,33 @@ int my_pthread_fastmutex_init(my_pthread_fastmutex_t *mp,
     mp->spins= MY_PTHREAD_FASTMUTEX_SPINS; 
   else
     mp->spins= 0;
+  mp->rng_state= 1;
   return pthread_mutex_init(&mp->mutex, attr); 
 }
 
+/**
+  Park-Miller random number generator. A simple linear congruential
+  generator that operates in multiplicative group of integers modulo n.
+
+  x_{k+1} = (x_k g) mod n
+
+  Popular pair of parameters: n = 2^32 − 5 = 4294967291 and g = 279470273.
+  The period of the generator is about 2^31.
+  Largest value that can be returned: 2147483646 (RAND_MAX)
+
+  Reference:
+
+  S. K. Park and K. W. Miller
+  "Random number generators: good ones are hard to find"
+  Commun. ACM, October 1988, Volume 31, No 10, pages 1192-1201.
+*/
+
+static double park_rng(my_pthread_fastmutex_t *mp)
+{
+  mp->rng_state= ((my_ulonglong)mp->rng_state * 279470273U) % 4294967291U;
+  return (mp->rng_state / 2147483647.0);
+}
+
 int my_pthread_fastmutex_lock(my_pthread_fastmutex_t *mp)
 {
   int   res;
@@ -458,8 +482,7 @@ int my_pthread_fastmutex_lock(my_pthread_fastmutex_t *mp)
       return res;
 
     mutex_delay(maxdelay);
-    maxdelay += ((double) random() / (double) RAND_MAX) * 
-	        MY_PTHREAD_FASTMUTEX_DELAY + 1;
+    maxdelay += park_rng(mp) * MY_PTHREAD_FASTMUTEX_DELAY + 1;
   }
   return pthread_mutex_lock(&mp->mutex);
 }