Fetching rows with a UROWID typed column segfaults if several rows have the same value

[markfinn]

cx_oracle 681c186
11xe database
12.2 client
64 bit linux.

with these tables:

CREATE TABLE change_log_target_test
(
num NUMBER NOT NULL PRIMARY KEY
)

CREATE TABLE change_log_test
(
changeid NUMBER NOT NULL PRIMARY KEY,
xrowid UROWID not null
)
this code segfaults:

import cx_Oracle
con = cx_Oracle.connect('user', 'pw', 'localhost')
c=con.cursor()
c.execute('delete from change_log_test')
c.execute('delete from change_log_target_test')
c.execute('insert into change_log_target_test(num) values(1)')
c.execute('insert into change_log_test(changeid, xrowid) values(1, (select rowid from change_log_target_test where num=1))')
c.execute('insert into change_log_test(changeid, xrowid) values(2, (select rowid from change_log_target_test where num=1))')
c.execute('insert into change_log_test(changeid, xrowid) values(3, (select rowid from change_log_target_test where num=1))')
con.commit()

c=con.cursor()
c.execute('select * from change_log_test')
c.fetchone()
c.fetchone()
c.fetchone()

You can do this all day if the rowids are different in each row, but the thrird row to have a duplicate value in the xrowid column segfaults in:

0 0x00007f54fe83ea90 in kgrdub2c () from /tmp/venvzz/oracle/instantclient_12_2/libclntsh.so.12.1
1 0x00007f54fd806f9f in kpuubrid2c () from /tmp/venvzz/oracle/instantclient_12_2/libclntsh.so.12.1
2 0x00007f5505ac2c24 in dpiOci__rowidToChar (rowid=0x32043f0, buffer=0x7ffd505ea037 "", bufferSize=0x3204418, error=0x7ffd505ea040)
at odpi/src/dpiOci.c:2242
3 0x00007f5505ad3a2d in dpiRowid_getStringValue (rowid=0x32043f0, value=value@entry=0x7ffd505ea0a0, valueLength=valueLength@entry=0x7ffd505ea09c)
at odpi/src/dpiRowid.c:90
4 0x00007f5505ad3b4a in RowidVar_GetValue (var=, data=) at src/StringVar.c:105
5 0x00007f5505abac1e in Variable_GetSingleValue (arrayPos=2, var=0x7f550e2ef500) at src/Variable.c:718
6 Cursor_CreateRow (self=self@entry=0x7f550d169df0, pos=2) at src/Cursor.c:925
7 0x00007f5505ae8a29 in Cursor_FetchOne (self=0x7f550d169df0, args=) at src/Cursor.c:1632
8 0x00000000004b9117 in call_function (oparg=, pp_stack=0x7ffd505ea200) at Python/ceval.c:4336
9 PyEval_EvalFrameEx (f=f@entry=0x7f550f125be8, throwflag=throwflag@entry=0) at Python/ceval.c:2989
10 0x00000000004bacb8 in PyEval_EvalCodeEx (co=co@entry=0x7f550d212030, globals=globals@entry=0x7f550ed365c8, locals=locals@entry=0x7f550ed365c8,
args=args@entry=0x0, argcount=argcount@entry=0, kws=kws@entry=0x0, kwcount=kwcount@entry=0, defs=defs@entry=0x0, defcount=defcount@entry=0,
closure=closure@entry=0x0) at Python/ceval.c:3584
...

[anthony-tuininga]

If you set the environment variable ORA_OCI_NO_OPTIMIZED_FETCH to the value 1 prior to running the program does the problem go away? If so, this is a known issue.

[markfinn]

That does seem to make it go away. Is that an issue with the database, instantclient, or something else?

[anthony-tuininga]

Its a bug in the OCI libraries: 26225722. Setting that environment variable is the only workaround for now that I am aware of. Sorry!

[markfinn]

Thanks.

[hexaclock]

Thank you so much!