invalid input syntax for integer: "\N" when gpload a text file - copy

Question

I found one strange problem. With greenplum gpload tool, I tried to import data from a single text file to greenplum db.
The content of file t1.out is:
\N|24234243
\N|\N
12342|\N
and gpload version is:
gpload version 5.3.0 build
commit:2155c5a8cf8bb7f13f49c6e248fd967a74fed591
and the table t1 is as follow:
test=# \d t1;
Table "public.t1"
Column | Type | Modifiers
--------+--------+-----------
id1 | bigint |
id2 | bigint |
when I use gpload with t1.yaml, I got following error:
2019-04-09 20:12:18|WARN|Please use following query to access the detailed error
2019-04-09 20:12:18|WARN|select * from p_read_error_log('ext_gpload_reusable_b7ef1344_5ac0_11e9_b6fc_fa163e2d09a1') where cmdtime > to_timestamp('1554811937.76')
and when I ran this sql(made small change only selecting two key fields) in postgresql, I got following errors:
errmsg | rawdata
invalid input syntax for integer: "\N", column id1 | \N|24234243
invalid input syntax for integer: "\N", column id1 | \N|\N
invalid input syntax for integer: "\N", column id2 | 12342|\N
It showed all the 3 lines were not imported with 'invalid input syntax for integer: "\N"'.
but I can use COPY command to import above 3 items into t1 successfully.
I tried several ways to find why, but failed. Part of my t1.yaml as follows:
- FORMAT: text
- DELIMITER: '|'
- ESCAPE: 'OFF'
- NULL_AS: '\N'
- ERROR_LIMIT: 100
BTW:https://gpdb.docs.pivotal.io/530/utility_guide/admin_utilities/gpload.html#topic1__cfnullas has shown that the default NULL_AS is \N, and gpload has found \N, and why it failed to mark the two field as NULL?
Any help is appreciated!

Answer 1

What version of GPDB are you using?
There was a known issue in v5 that was fixed in 5.6+
https://gpdb.docs.pivotal.io/560/relnotes/GPDB_561_README.html
29197 - gpload/ gpfdist
When running a gpload operation, the gpfdist utility did not recognize a \N as the NULL character when the gpload configuration file specified a null character null_as: '\N'. When processing the configuration file, the gpload utility incorrectly escaped the backslash () with another backslash.
This issue has been resolved. The gpload utility has been improved to properly handle a backslash when processing the null_as property.