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Merge of 5.1-main into 5.1-maria. There were no changes to storage/myisam, or mysql-test/t/*myisam*.

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However there were three new tests mysql-test/suite/parts/t/partition*myisam.test, of which I make here
copies for Maria.
This commit is contained in:
Guilhem Bichot
2008-11-21 15:21:50 +01:00
parent 8d96bcda72 1d521f6c20
commit 33b194c36e
400 changed files with 265530 additions and 236652 deletions
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27
mysys/thr_mutex.c
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@ -458,9 +458,33 @@ 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;
@ -478,8 +502,7 @@ 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);
}