Re: [HACKERS] Transactions involving multiple postgres foreign servers - Mailing list pgsql-hackers

From Robert Haas
Subject Re: [HACKERS] Transactions involving multiple postgres foreign servers
Date
Msg-id CA+TgmoaQ6kTTzq4uNZV6MULNBa5ciP-LbxWb4P+_v4ChbwYn3w@mail.gmail.com
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In response to RE: [HACKERS] Transactions involving multiple postgres foreignservers  ("Tsunakawa, Takayuki" <tsunakawa.takay@jp.fujitsu.com>)
Responses Re: [HACKERS] Transactions involving multiple postgres foreign servers
List pgsql-hackers
On Wed, Dec 27, 2017 at 9:40 PM, Tsunakawa, Takayuki
<tsunakawa.takay@jp.fujitsu.com> wrote:
> (1)
> Why don't you use the existing global variable MyXactFlags instead of the new TransactionDidWrite?  Or, how about
usingXactLastRecEnd != 0 to determine the transaction did any writes?  When the transaction only modified temporary
tableson the local database and some data on one remote database, I think 2pc is unnecessary. 

If I understand correctly, XactLastRecEnd can be set by, for example,
a HOT cleanup record, so that doesn't seem like a good thing to use.
Whether we need to use 2PC across remote nodes seems like it shouldn't
depend on whether a local SELECT statement happened to do a HOT
cleanup or not.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company


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