Re: [PATCH 0/3] Another approach to large transactions

From: Stefan Beller <sbeller@google.com>
Date: Apr 20, 2015, 22:26 UTC
Message-ID: <CAGZ79kZWm=Mi6o4jMNthiDRcR9irs_5MyRuEmHdDSrn-JFpQ=g@mail.gmail.com>
In-Reply-To: <CAGZ79kYEbnZvgdhjPvc2rR7QKp-CjUB3Ytqsp8JK2QBqzuUowA@mail.gmail.com>

On Fri, Apr 17, 2015 at 4:31 PM, Stefan Beller <sbeller@google.com> wrote:

Show 12 quoted lines

> On Fri, Apr 17, 2015 at 3:17 PM, Stefan Beller <sbeller@google.com> wrote:
>> On Fri, Apr 17, 2015 at 3:12 PM, Junio C Hamano <gitster@pobox.com> wrote:
>>>
>>> This is now pushed out and sitting at the tip of 'pu'.  It seems to
>>> break one of the tests in 1400 when merged to 'next', but I didn't
>>> look it closely.
>>>
>>> Thanks.
>>
>> ok, I'll look more closely.
>
> Apparently I screwed up even before sending the patches over the wire.

For the deleting refs test failing: The problem comes from guessing the number of fds we're allowed to use. At first I thought it was a fundamental issue with the code being broken, but it turns out we just need a larger offset as we apparently have 9 files open already, before the transaction even starts. I did not expect the number to be that high, which is why I came up with the arbitrary number of 8 (3 for stdin/out/err, maybe packed refs and reflog so I guessed, 8 would do fine).

I am not sure if the 9 is a constant or if it scales to some unknown property yet. So to make the series work, all we need is:

- int remaining_fds = get_max_fd_limit() - 8;
+ int remaining_fds = get_max_fd_limit() - 9;

I am going to try to understand where the 9 comes from and resend the patches.

Thanks, Stefan