Hello Tom,

SELECT 1, 2 \; SELECT 3;
\into one two three

Yeah, that's seriously nasty action-at-a-distance in my view.  I'd be okay

SELECT 1, 2 \into one two
SELECT 3 \into three

ISTM that is not the same, because then you would have two queries (over the network) instead of one, so you pay the network latency twice?

but I do not think that a metacommand on a following line should
retroactively affect the execution of a prior command, much less commands
before the last one.

Nope. The meta-command applies to the preceeding SQL command... which happens to be a \;-compound command. ISTM that all is logically fine.

Some motivation about the feature (not its syntax or implementation), from a benchmarking perspective:

- clients MUST read the server answers and possibly reuse them, hence a proposed \into feature. Discarding the answer as pgbench does not really comply with typical benchmark rules, eg from tpc-b:

  """1.3.2 Each transaction shall return to the driver the Account_Balance
     resulting from successful commit of the transaction.

  Comment: It is the intent of this clause that the account balance in the
  database be returned to the driver, i.e., that the application retrieve
  the account balance."""

- latency is important to applications (eg web applications), thus the ability to compound statements is a good thing. However, if in a bench one can compound statements but not retrieve their values, it fails the previous "retrieve the value" requirement.

So basically I wish to avoid splitting compound queries and paying latency just because of a lack of syntax to do the right thing, hence the proposed feature which can retrieve data from various parts of a compound statement.


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