Re: Conflict handling for COPY FROM

On 11.11.2019 16:00, Surafel Temesgen wrote:
>
>
>     Next, you use DestRemoteSimple for returning conflicting tuples back:
>
>     +        dest = CreateDestReceiver(DestRemoteSimple);
>     +        dest->rStartup(dest, (int) CMD_SELECT, tupDesc);
>
>     However, printsimple supports very limited subset of built-in
>     types, so
>
>     CREATE TABLE large_test (id integer primary key, num1 bigint, num2
>     double precision);
>     COPY large_test FROM '/path/to/copy-test.tsv';
>     COPY large_test FROM '/path/to/copy-test.tsv' ERROR 3;
>
>     fails with following error 'ERROR:  unsupported type OID: 701', which
>     seems to be very confusing from the end user perspective. I've
>     tried to
>     switch to DestRemote, but couldn't figure it out quickly.
>
>
> fixed

Thanks, now it works with my tests.

1) Maybe it is fine, but now I do not like this part:

+    portal = GetPortalByName("");
+    dest = CreateDestReceiver(DestRemote);
+    SetRemoteDestReceiverParams(dest, portal);
+    dest->rStartup(dest, (int) CMD_SELECT, tupDesc);

Here you implicitly use the fact that portal with a blank name is always 
created in exec_simple_query before we get to this point. Next, you 
create new DestReceiver and set it to this portal, but it is also 
already created and set in the exec_simple_query.

Would it be better if you just explicitly pass ready DestReceiver to 
DoCopy (similarly to how it is done for T_ExecuteStmt / ExecuteQuery), 
as it may be required by COPY now?

2) My second concern is that you use three internal flags to track 
errors limit:

+    int            error_limit;    /* total number of error to ignore */
+    bool        ignore_error;    /* is ignore error specified? */
+    bool        ignore_all_error;    /* is error_limit -1 (ignore all 
error)
+                                     * specified? */

Though it seems that we can just leave error_limit as a user-defined 
constant and track errors with something like errors_count. In that case 
you do not need auxiliary ignore_all_error flag. But probably it is a 
matter of personal choice.


Regards

-- 
Alexey Kondratov

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