I am able to copy a row with a 127megabyte column, but not with one that is 399 megabytes.
Here is the log output of the one that fails:
[4272-42.487]SQL_VARBINARY: about to call convert_to_pgbinary, used = 399966009
[4272-42.488]STATEMENT ERROR: func=enlarge_statement, desc='', errnum=1, errmsg='Query buffer allocate error in copy_statement_with_parameters'
[4272-42.496]CONN ERROR: func=enlarge_statement, desc='', errnum=0, errmsg='(NULL)'
[4272-42.499]retval=-1
[4272-42.500][[SQLGetDiagFieldW]] Handle=(3,08F47DD0) Rec=1 Id=4 info=(09BF6788,12)
[4272-42.500]PGAPI_GetDiagField entering rec=1[4272-42.500]ER_ReturnError: status = 1, msg = #Query buffer allocate error in copy_statement_with_parameters#
[4272-42.501] szSqlState = 'HY000',len=61, szError='(null)'
[4272-42.501]PGAPI_GetDiagField exiting 0
