Re: Issue related with patitioned table:How can I quickly determine which child table my record is in,given a specific primary key value?
| От | James(王旭) |
|---|---|
| Тема | Re: Issue related with patitioned table:How can I quickly determine which child table my record is in,given a specific primary key value? |
| Дата | |
| Msg-id | tencent_3398A66F571334E95E5B4093@qq.com обсуждение исходный текст |
| Ответ на | Re: Issue related with patitioned table:How can I quickly determinewhich child table my record is in,given a specific primary key value? (Luca Ferrari <fluca1978@gmail.com>) |
| Ответы |
Re: Issue related with patitioned table:How can I quickly determine which child table my record is in,given a specific primary key value?
|
| Список | pgsql-general |
Thanks you Luca.
Yes my intention was " SELECT (hashint2(6365::SMALLINT)% 3) ", that's my mistake, thank you for pointing out.
Actually I just did a simple query in my single table:
SELECT distinct(symbol_id) FROM xxxx_0
and I got these results:
"symbol_id"
6521
1478
1964
5642
7470
1158
2429
9882
4542
5196
9178
8303
1091
9435
8133
1437
9072
From these results I can tell the route to a table is not even related with the mod function, right?
So It's hard for me to do any kind of guesses...
------------------ Original ------------------
From: "Luca Ferrari"<fluca1978@gmail.com>;
Date: Wed, Jul 17, 2019 05:13 PM
To: "王旭"<wangxu@gu360.com>;
Cc: "pgsql-general"<pgsql-general@lists.postgresql.org>;
Subject: Re: Issue related with patitioned table:How can I quickly determine which child table my record is in,given a specific primary key value?
On Wed, Jul 17, 2019 at 9:19 AM 王旭 <wangxu@gu360.com> wrote:
> I tried something like this: e.g., for symbol_id 6365,
> SELECT (hashint2(6365::SMALLINT)% 10)
shouldn't this be modulus 3 instead of 10?
The problem is that record 6365 is not where you expected to be?
As far as I know, there is no easy user-level way to get the route to
a table, but you can juggle with the expression that defined each
table and make a good guess.
However, your query should give a good idea:
# SELECT 'my_table_' || (hashint2(6365::smallint)% 3);
?column?
------------
my_table_2
> I tried something like this: e.g., for symbol_id 6365,
> SELECT (hashint2(6365::SMALLINT)% 10)
shouldn't this be modulus 3 instead of 10?
The problem is that record 6365 is not where you expected to be?
As far as I know, there is no easy user-level way to get the route to
a table, but you can juggle with the expression that defined each
table and make a good guess.
However, your query should give a good idea:
# SELECT 'my_table_' || (hashint2(6365::smallint)% 3);
?column?
------------
my_table_2
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