On 2021/04/08 13:43, Kohei KaiGai wrote:
In case when a local table (with no children) has same contents,
TRUNCATE command
witll remove the entire table contents.

But if there are local child tables that inherit the local parent table, and TRUNCATE 
ONLY <parent table> is executed, only the contents in the parent will be 
truncated. I was thinking that this behavior should be applied to the foreign table 
whose remote (parent) table have remote child tables.

So what we need to reach the consensus is; how far ONLY option affects. Please 
imagine the case where we have

(1) local parent table, also foreign table of remote parent table
(2) local child table, inherits local parent table
(3) remote parent table
(4) remote child table, inherits remote parent table

I think that we agree all (1), (2), (3) and (4) should be truncated if local 
parent table (1) is specified without ONLY in TRUNCATE command. OTOH, if ONLY 
is specified, we agree that at least local child table (2) should NOT be 
truncated.

So the remaining point is; remote tables (3) and (4) should be truncated or not 
when ONLY is specified? You seem to argue that both should be truncated by 
removing extra list. I was thinking that only remote parent table (3) should be 
truncated. That is, IMO we should treat the truncation on foreign table as the 
same as that on its forein data source.

Other people might think neither (3) nor (4) should be truncated in that case 
because ONLY should affect only the table directly specified in TRUNCATE 
command, i.e., local parent table (1). For now this also looks good to me.

Regards,

--
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION


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