[pacman-dev] [PATCH v2] Introduce alpm_dbs_update() function for parallel db updates

[Allan McRae]

On 14/4/20 4:33 am, Anatol Pomozov wrote:
> Hi
> 
> On Thu, Mar 12, 2020 at 6:16 PM Allan McRae <allan at archlinux.org> wrote:
>>
>> On 9/3/20 6:59 am, Anatol Pomozov wrote:
>>> This is an equivalent of alpm_db_update but for multiplexed (parallel)
>>> download. The difference is that this function accepts list of
>>> databases to update. And then ALPM internals download it in parallel if
>>> possible.
>>>
>>> Add a stub for _alpm_multi_download the function that will do parallel
>>> payloads downloads in the future.
>>>
>>> Introduce dload_payload->filepath field that contains url path to the
>>> file we download. It is like fileurl field but does not contain
>>> protocol/server part. The rationale for having this field is that with
>>> the curl multidownload the server retry logic is going to move to a curl
>>> callback. And the callback needs to be able to reconstruct the 'next'
>>> fileurl. One will be able to do it by getting the next server url from
>>> 'servers' list and then concat with filepath. Once the 'parallel download'
>>> refactoring is over 'fileurl' field will go away.
>>>
>>> Signed-off-by: Anatol Pomozov <anatol.pomozov at gmail.com>


<snip>

>>
>>> +                     sig_payload->handle = handle;
>>> +                     sig_payload->force = dbforce;
>>
>> Always "force" the signature.
>> sig_payload->force = 1;
> 
> I sent a change with "->force = 1;" and it got applied to Allan's
> patchqueu. But I would like to review this line one more time and
> switch it back to "sig_payload->force = dbforce;"
> 
> Having "sig_payload->force = 1;" forces ALPM to ignore modification
> time and always download the file. It was fine before when *.sig file
> downloaded only after we found that *.db file is changed (in this case
> *.sig is changed as well). With the new logic we start downloading the
> files in parallel. *.db file content is download only if modification
> time is newer. But setting "sig_payload->force = 1;" forced
> downloading *.sig file content every time. And most of the time it is
> unneeded. We need to download the *.sig file content only when it
> changed.
> 
> Thus I propose to make this line to "sig_payload->force = dbforce;"
> (i.e. force download signature only when we force download the *.db
> file).
> 

This is good reasoning.  I'll edit that back into the patch on my
patchqueue branch.

A