From: | James Keener <jim(at)jimkeener(dot)com> |
---|---|
To: | lists(at)alteeve(dot)ca |
Cc: | "pgsql-generallists(dot)postgresql(dot)org" <pgsql-general(at)lists(dot)postgresql(dot)org> |
Subject: | Re: Weird procedure question |
Date: | 2018-09-25 05:47:04 |
Message-ID: | CAG8g3ty0hjVd+74hjFJVD0o3a8PCuPRL3Dg=xOfkv5Lcmu_pPQ@mail.gmail.com |
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Thread: | |
Lists: | pgsql-general |
Also, modified time doesn't need to be the current time, if it starts as
"null" and is set on the first update, and all subsequent updates, the
pre-update modified time could be used to help key the history pk.
Jim
On Tue, Sep 25, 2018 at 1:45 AM James Keener <jim(at)jimkeener(dot)com> wrote:
> v3 UUIDs are basically MD5 hashes (v5 is sha1?). So for the same input
> you'll always get the same hash.
>
> I had assumed the modified time would be the same; if that's not, then I'm
> not sure and my gut tells me this becomes A Really Hard Problemâ„¢.
>
> Jim
>
> On Tue, Sep 25, 2018 at 1:38 AM digimer <lists(at)alteeve(dot)ca> wrote:
>
>> On 2018-09-25 1:33 a.m., James Keener wrote:
>> > Do you need a single field for the pk or can you just make it the
>> > (original_table_pk, modified_time)? Alternatively, you could generate
>> > a uuid v3 from the (original_table_pk, modified_time) using something
>> > like uuid_generate_v3(uuid_nil(), original_table_pk || ":" ||
>> > modified_time)?
>>
>> I need to preset the modified_time, I can't use now() or else the value
>> would differ between databases. Also, unless I am missing something,
>> uuid_generate_v3() would generate a different UUID per trigger of the
>> procedure, so I'd end up with different history_uuids on each database
>> that I ran the query against.
>>
>> If I am missing something (and entirely possible I am), please hit me
>> with a clue stick. :)
>>
>> digimer
>>
>>
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