Date: Sat, 22 Feb 2003 11:56:54 -0500 From: "Simon" <simon@optinet.com> To: "Martin Blapp" <mb@imp.ch> Cc: "freebsd-bugs@FreeBSD.org" <freebsd-bugs@FreeBSD.org>, "HiTech Creations Support" <htsupp@hitechcreations.com> Subject: Re: kern/39878: mysqld process suddenly runs at 99% CPU without load, and a restart of mysqld is required. Message-ID: <20030222165740.92AF243FBD@mx1.FreeBSD.org> In-Reply-To: <20030222175014.P59307@levais.imp.ch>
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So building with "WITH_LINUXTHREADS=yes" is perfectly safe in 4.7-R and later?
PS: i'm not sure what you mean by *now*, thus the question.
-Simon
On Sat, 22 Feb 2003 17:56:41 +0100 (CET), Martin Blapp wrote:
>
>Hi,
>
>> @${ECHO} " WITH_LINUXTHREADS=yes Use the linuxthreads pthread library."
>> @${ECHO} " This is _NOT_ recommended for production"
>> @${ECHO} " servers. Expect problems when enabled."
>
>I know that. It was true until now.
>
>>
>> what is the patch below for?
>
>Mysql did not kill it's threads when using WITH_LINUXTHREADS=yes. So
>you were running out of processes and fd's after some time.
>
>Quoting Rick Reed from Yahoo!
>
>> The socket on which MySQL listens for new connections on a blocking
>> socket most of the time but is set to non-blocking during the
>> accept() of the new connection. Due to a bug in the kernel, the new
>> socket returned by accept() is a blocking socket but returns the
>> O_NONBLOCK flag when queried via fcntl(F_GETFL). That is, the file
>> descriptor and the underlying socket don't agree on the blocking
>> mode.
>>
>> Since MySQL determines via fcntl(F_GETFL) that the socket is
>> non-blocking, it expects the first read() in my_real_read to not
>> block, so it doesn't enable the timeout alarm. However, the read
>> does block, and thus there's no timeout alarm. The thread kill
>> (which relies on rescheduling the timeout alarm) also does not work
>> as a consequence.
>
>Martin
>
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