Hello all,
I'm working on a foreign data wrapper that uses INSERT, and I noticed some odd behaviour. If I insert just one row, the TupleDesc->attr[0]->attname.data has the column names in it. However, in a multi-row string, all those are empty strings:
int i;
FormData_pg_attribute *attr;
TupleDesc tupleDesc;
tupleDesc = slot->tts_tupleDescriptor;
for (i = 0; i < tupleDesc -> natts; i++) {
attr = tupleDesc->attrs[i];
elog(WARNING, "found column '%s'", attr->attname.data);
}
Now with a single row insert, this works as you'd expect:
liz=# INSERT INTO bhtable (key, value) VALUES ('hello', 'world');
WARNING: found column 'key'
WARNING: found column 'value'
INSERT 0 1
But with a multi-row, all the column names are empty:
liz=# INSERT INTO bhtable (key, value) VALUES ('hello', 'world'), ('goodmorning', 'world');
WARNING: found column ''
WARNING: found column ''
WARNING: found column ''
WARNING: found column ''
INSERT 0 2
It doesn't seem unreasonable to me that this data wouldn't be duplicated, but there's no mention of how I would go about retriving these column names for my individual rows, and most foreign data wrappers I can find are write-only.
Am I missing something obvious? Is this a bug?
Thanks,
Liz