Note: Tested in Oracle 19c with:
db_block_size 8192 (default)
db_securefile permitted (default)
1. Test Code
We create a range partitioned table with one basicfile LOB:
drop table test_tab purge;
create table test_tab (
id number,
code varchar2(10),
name varchar2(100),
created_date date,
text clob,
constraint test_tab_pk primary key (id)
)
lob (text) store as basicfile (
--lob (text) store as securefile test_tab_sf_text (
--compress medium
enable storage in row
-- chunk 32768 -- 8192 (default), 32768=4*8192, no effect for securefile
)
partition by range (created_date)
(
partition test_tab_2026 values less than (maxvalue)
);
create index test_tab#code on test_tab (code);
create index test_tab#created_date on test_tab (created_date) local;
create or replace procedure test_tab_fill(p_row_cnt number, p_lob_len_kb number) as
l_lob clob := empty_clob();
l_len number;
begin
insert into test_tab
select level id, rpad('ABC', 8, 'X') code, rpad('ABC', 80, 'X') name, to_date('22-NOV-202'||(mod(level,7)),'DD-MON-YYYY') created_date, empty_clob() text
from dual connect by level <= p_row_cnt;
dbms_lob.createtemporary(l_lob, true, dbms_lob.session);
for i in 1..p_lob_len_kb loop
dbms_lob.append(dest_lob => l_lob, src_lob => rpad('ABC', 1024, 'X'));
end loop;
update test_tab set text = rownum||l_lob;
commit;
end;
/
2. Basicfile Test
We will make two Basicfile tests, one with LOB chunk size 8192, one with LOB chunk size 32768.
2.1 Basicfile with Chunk 8192
We prepare and run test with:
-- Fill table with 1000 rows, each contain one 8 MB Clob
exec test_tab_fill(1000, 1024*8);
exec dbms_stats.gather_table_stats(user, 'TEST_TAB', cascade => true);
select round(sum(length(text)/1024/1024)) mb, count(*), round(sum(length(text))/count(*)/1024) avg_len_kb from test_tab;
MB COUNT(*) AVG_LEN_KB
---------- ---------- ----------
8000 1000 8192
alter session set max_dump_file_size=unlimited;
alter session set tracefile_identifier = 'test_b8192';
alter session set events '10046 trace name context forever, level 12';
alter table test_tab
split partition test_tab_2026 at (date'2025-12-31')
into (partition test_tab_2025,
partition test_tab_2026)
update indexes --parallel 8
;
Elapsed: 00:08:56.18
alter session set events '10046 trace name context off';
Here the SQL trace:
********************************************************************************
alter table test_tab
split partition test_tab_2026 at (date'2025-12-31')
into (partition test_tab_2025,
partition test_tab_2026)
update indexes --parallel 8
call count cpu elapsed disk query current rows
------- ------ -------- ---------- ---------- ---------- ---------- ----------
Parse 1 0.00 0.00 0 0 0 0
Execute 1 99.30 533.69 2064038 2113185 5401904 1000
Fetch 0 0.00 0.00 0 0 0 0
------- ------ -------- ---------- ---------- ---------- ---------- ----------
total 2 99.31 533.70 2064038 2113185 5401904 1000
Misses in library cache during parse: 1
Optimizer mode: ALL_ROWS
Parsing user id: 49
Number of plan statistics captured: 1
Rows (1st) Rows (avg) Rows (max) Row Source Operation
---------- ---------- ---------- ---------------------------------------------------
0 0 0 LOAD AS SELECT TEST_TAB (cr=2112099 pr=2064025 pw=2064028 time=533571542 us starts=1)
1000 1000 1000 PARTITION RANGE SINGLE PARTITION: 1 1 (cr=31 pr=1 pw=0 time=9524 us starts=1 cost=2 size=184336 card=82)
1000 1000 1000 TABLE ACCESS FULL TEST_TAB PARTITION: 1 1 (cr=31 pr=1 pw=0 time=8397 us starts=1 cost=2 size=184336 card=82)
Elapsed times include waiting on following events:
Event waited on Times Max. Wait Total Waited
---------------------------------------- Waited ---------- ------------
db file sequential read 364 0.01 0.26
control file sequential read 3260 0.11 1.97
datafile move cleanup during resize 163 0.00 0.02
Disk file operations I/O 489 0.01 0.14
Data file init write 187 0.02 0.46
direct path sync 163 0.00 0.03
db file single write 163 0.02 0.04
control file parallel write 489 0.04 0.94
DLM cross inst call completion 163 0.02 0.21
direct path read 2063998 0.24 433.13
direct path write 1906 0.06 4.93
log file switch (private strand flush incomplete)
1 0.02 0.02
local write wait 16 0.00 0.01
reliable message 8 0.00 0.00
enq: RO - fast object reuse 4 0.00 0.00
enq: CR - block range reuse ckpt 4 0.00 0.00
write complete waits 1 0.00 0.00
PGA memory operation 1 0.00 0.00
SQL*Net message to client 1 0.00 0.00
SQL*Net message from client 1 0.00 0.00
********************************************************************************
select event, p1, p2, p3, p1text, p2text, p3text, row_wait_obj#, row_wait_file#, row_wait_block#, row_wait_row#
from v$session where sid = 912;
EVENT P1 P2 P3 P1TEXT P2TEXT P3TEXT ROW_WAIT_OBJ# ROW_WAIT_FILE# ROW_WAIT_BLOCK# ROW_WAIT_ROW#
----------------- ----- -------- --- ------------ ----------- ---------- ------------- -------------- --------------- -------------
direct path write 22 5376932 1 file number first dba block cnt 6244876 22 3621774 0
select sample_time, event, p1, p2, p3, p1text, p2text, p3text, current_obj#, current_file#, current_block#, current_row#
from v$active_session_history t
where sample_time > sysdate-35/1440
and session_id = 912
and event in ('direct path read', 'direct path write')
order by t.sample_time;
SAMPLE_TIME EVENT P1 P2 P3 P1TEXT P2TEXT P3TEXT CURRENT_OBJ# CURRENT_FILE# CURRENT_BLOCK# CURRENT_ROW#
-------------------- ----------------- ----- -------- --- ------------ ---------- ---------- ------------ ------------- -------------- ------------
03-JUL-2026 13:09:37 direct path write 22 5376932 1 file number first dba block cnt 6244876 22 3621774 0
03-JUL-2026 13:11:18 direct path write 22 5673340 1 file number first dba block cnt 6244876 22 2374684 0
03-JUL-2026 13:12:30 direct path write 22 5890030 1 file number first dba block cnt 6244876 22 3427384 0
SAMPLE_TIME EVENT P1 P2 P3 P1TEXT P2TEXT P3TEXT CURRENT_OBJ# CURRENT_FILE# CURRENT_BLOCK# CURRENT_ROW#
-------------------- ----------------- ----- -------- --- ------------ ---------- ---------- ------------ ------------- -------------- ------------
03-JUL-2026 13:12:41 direct path read 22 3609403 1 file number first dba block cnt 6244876 22 3609403 0
03-JUL-2026 13:12:39 direct path read 22 3573182 1 file number first dba block cnt 6244876 22 3573182 0
03-JUL-2026 13:12:36 direct path read 22 3514427 1 file number first dba block cnt 6244876 22 3514427 0
select * from sys.lobfrag$ where fragobj# = 6244876;
FRAGOBJ# PARENTOBJ# TABFRAGOBJ# INDFRAGOBJ# FRAG# F TS# FILE# BLOCK# CHUNK PCTVERSION$ FRAGFLAGS FRAGPRO SPARE1 SPARE2 SPARE3
---------- ---------- ----------- ----------- ---------- - ---------- ---------- ---------- ---------- ----------- ---------- ---------- ---------- ---------- ----------
6244876 6244875 6244874 6244878 10 P 4140 1024 999930 1 10 97 2
select object_name, subobject_name, object_id, data_object_id, object_type from dba_objects where object_name = 'TEST_TAB';
OBJECT_NAM SUBOBJECT_NAME OBJECT_ID DATA_OBJECT_ID OBJECT_TYPE
---------- --------------- ---------- -------------- ---------------
TEST_TAB TEST_TAB_2025 6244883 6244883 TABLE PARTITION
TEST_TAB TEST_TAB_2026 6244874 6244884 TABLE PARTITION
TEST_TAB 6244873 TABLE
select table_name, column_name, segment_name, index_name, chunk, securefile from dba_lobs where table_name = 'TEST_TAB';
TABLE_NAME COLUMN_NAM SEGMENT_NAME INDEX_NAME CHUNK SEC
---------- ---------- ------------------------- ------------------------- ---------- ---
TEST_TAB TEXT SYS_LOB0006244873C00005$$ SYS_IL0006244873C00005$$ 8192 NO
select table_name, column_name, lob_name, partition_name, lob_partition_name, lob_indpart_name, partition_position, chunk
from dba_lob_partitions where table_name = 'TEST_TAB';
TABLE_NAME COLUMN_NAM LOB_NAME PARTITION_NAME LOB_PARTITION_NAME LOB_INDPART_NAME PARTITION_POSITION CHUNK
---------- ---------- ------------------------- --------------- -------------------- -------------------- ------------------ ----------
TEST_TAB TEXT SYS_LOB0006244873C00005$$ TEST_TAB_2025 SYS_LOB_P647334 SYS_IL_P647336 1 8192
TEST_TAB TEXT SYS_LOB0006244873C00005$$ TEST_TAB_2026 SYS_LOB_P647335 SYS_IL_P647337 2 8192
$ > fgrep 'direct path read' testdb_ora_2472818_test_b8192.trc
WAIT #139722977275192: nam='direct path read' ela= 527 file number=22 first dba=1047862 block cnt=1 obj#=6244876 tim=24601964026630
WAIT #139722977275192: nam='direct path read' ela= 356 file number=22 first dba=1047863 block cnt=1 obj#=6244876 tim=24601964027037
WAIT #139722977275192: nam='direct path read' ela= 934 file number=22 first dba=1047857 block cnt=1 obj#=6244876 tim=24601964028034
$ > fgrep 'direct path read' testdb_ora_2472818_test_b8192.trc|wc
2063998 30959970 270521981
$ > strace -p
io_submit(0x7f13d15dd000, 1, [{aio_data=0x7f13c9a50488, aio_lio_opcode=IOCB_CMD_PREAD, aio_fildes=264, aio_buf=0x7f13caee1000, aio_nbytes=8192, aio_offset=24147320832}]) = 1
io_getevents(0x7f13d15dd000, 2, 128, [{data=0x7f13ca651ef8, obj=0x7f13ca651ef8, res=8192, res2=0}, {data=0x7f13c9a50488, obj=0x7f13c9a50488, res=8192, res2=0}], {tv_sec=0, tv_nsec=0}) = 2
io_submit(0x7f13d15dd000, 1, [{aio_data=0x7f13ca6525f8, aio_lio_opcode=IOCB_CMD_PWRITE, aio_fildes=264, aio_buf="(\242\0\0\261\3210\0\261\341\323:|\f\2\4\320A\0\0XJ_\0\0\0\0\1\0\0!\v"..., aio_nbytes=8192, aio_offset=26209558528}]) = 1
Note FRAGOBJ# = 6244876 in sys.lobfrag$ is a temporay object used during partition split, it does not exist on dba_objects.
select * from dba_objects where object_id = 6244876 or data_object_id = 6244876;
no rows selected
select * from sys.obj$ where obj# = 6244876 or dataobj# = 6244876;
no rows selected
Oracle partition split using Parallel DML (PDML) does not work for BASICFILE LOB segment when specifying parallel clause
although Xplan still showed "PX COORDINATOR".
********************************************************************************
ALTER TABLE t
SPLIT PARTITION t1_2017 AT (TO_DATE('31-DEC-2015 23:59:59', 'DD-MON-YYYY HH24:MI:SS'))
INTO (PARTITION t1_2015,
PARTITION t1_2017)
UPDATE INDEXES PARALLEL 8
call count cpu elapsed disk query current rows
------- ------ -------- ---------- ---------- ---------- ---------- ----------
Parse 1 0.00 0.00 0 0 0 0
Execute 1 4.85 7.69 88712 95141 235000 192
Fetch 0 0.00 0.00 0 0 0 0
------- ------ -------- ---------- ---------- ---------- ---------- ----------
total 2 4.85 7.69 88712 95141 235000 192
Misses in library cache during parse: 1
Optimizer mode: ALL_ROWS
Parsing user id: 49
Number of plan statistics captured: 1
Rows (1st) Rows (avg) Rows (max) Row Source Operation
---------- ---------- ---------- ---------------------------------------------------
0 0 0 LOAD AS SELECT T (cr=94793 pr=88708 pw=88709 time=7609875 us starts=1)
192 192 192 PX COORDINATOR (cr=3 pr=0 pw=0 time=33097 us starts=1)
0 0 0 PX SEND QC (RANDOM) :TQ10000 (cr=0 pr=0 pw=0 time=0 us starts=0 cost=2 size=41280 card=192)
0 0 0 PX BLOCK ITERATOR PARTITION: 1 1 (cr=0 pr=0 pw=0 time=0 us starts=0 cost=2 size=41280 card=192)
0 0 0 TABLE ACCESS FULL T1 PARTITION: 1 1 (cr=0 pr=0 pw=0 time=0 us starts=0 cost=2 size=41280 card=192)
Elapsed times include waiting on following events:
Event waited on Times Max. Wait Total Waited
---------------------------------------- Waited ---------- ------------
PX Deq: Join ACK 8 0.00 0.00
PX Deq: Parse Reply 8 0.01 0.02
PX Deq: Execute Reply 13 0.00 0.00
db file sequential read 8 0.00 0.02
direct path read 88702 0.00 3.76
direct path write 198 0.02 0.05
PX Deq: Signal ACK EXT 8 0.00 0.00
PX Deq: Slave Session Stats 8 0.00 0.00
enq: PS - contention 1 0.00 0.00
reliable message 8 0.00 0.00
enq: RO - fast object reuse 4 0.00 0.00
enq: CR - block range reuse ckpt 4 0.00 0.00
log file sync 1 0.00 0.00
PGA memory operation 1 0.00 0.00
SQL*Net message to client 1 0.00 0.00
SQL*Net message from client 1 0.01 0.01
********************************************************************************
2.2 Basicfile with Chunk 32768
We further make a test of LOB Chunk Size: 32768 (4*8192):
--------------------- chunk 32768 -----------------------
drop table test_tab purge;
create table test_tab (
id number,
code varchar2(10),
name varchar2(100),
created_date date,
text clob,
constraint test_tab_pk primary key (id)
)
lob (text) store as basicfile (
--lob (text) store as securefile test_tab_sf_text (
--compress medium
enable storage in row
chunk 32768 -- 8192 (default), 32768=4*8192, no effect for securefile
)
partition by range (created_date)
(
partition test_tab_2026 values less than (maxvalue)
);
create index test_tab#code on test_tab (code);
create index test_tab#created_date on test_tab (created_date) local;
-- Fill table with 1000 rows, each contain one 8 MB Clob
exec test_tab_fill(1000, 1024*8);
exec dbms_stats.gather_table_stats(user, 'TEST_TAB', cascade => true);
alter session set max_dump_file_size=unlimited;
alter session set tracefile_identifier = 'test_b32768';
alter session set events '10046 trace name context forever, level 12';
alter table test_tab
split partition test_tab_2026 at (date'2025-12-31')
into (partition test_tab_2025,
partition test_tab_2026)
update indexes --parallel 8
;
Elapsed: 00:05:49.63
alter session set events '10046 trace name context off';
Here SQL trace:
********************************************************************************
alter table test_tab
split partition test_tab_2026 at (date'2025-12-31')
into (partition test_tab_2025,
partition test_tab_2026)
update indexes --parallel 8
call count cpu elapsed disk query current rows
------- ------ -------- ---------- ---------- ---------- ---------- ----------
Parse 1 0.00 0.00 0 0 0 0
Execute 1 34.70 349.05 2064014 2094838 2877842 1000
Fetch 0 0.00 0.00 0 0 0 0
------- ------ -------- ---------- ---------- ---------- ---------- ----------
total 2 34.70 349.05 2064014 2094838 2877842 1000
Misses in library cache during parse: 1
Optimizer mode: ALL_ROWS
Parsing user id: 49
Number of plan statistics captured: 1
Rows (1st) Rows (avg) Rows (max) Row Source Operation
---------- ---------- ---------- ---------------------------------------------------
0 0 0 LOAD AS SELECT TEST_TAB (cr=2093924 pr=2064009 pw=2064028 time=348998633 us starts=1)
1000 1000 1000 PARTITION RANGE SINGLE PARTITION: 1 1 (cr=30 pr=0 pw=0 time=9147 us starts=1 cost=10 size=281000 card=1000)
1000 1000 1000 TABLE ACCESS FULL TEST_TAB PARTITION: 1 1 (cr=30 pr=0 pw=0 time=8270 us starts=1 cost=10 size=281000 card=1000)
Elapsed times include waiting on following events:
Event waited on Times Max. Wait Total Waited
---------------------------------------- Waited ---------- ------------
direct path read 509092 0.42 313.25
direct path write 1489 0.05 2.25
db file sequential read 14 0.02 0.08
PGA memory operation 2 0.00 0.00
reliable message 8 0.00 0.00
enq: RO - fast object reuse 4 0.00 0.00
enq: CR - block range reuse ckpt 4 0.00 0.00
write complete waits 1 0.00 0.00
SQL*Net message to client 1 0.00 0.00
SQL*Net message from client 1 0.01 0.01
********************************************************************************
select table_name, column_name, segment_name, index_name, chunk, securefile from dba_lobs where table_name = 'TEST_TAB';
TABLE_NAME COLUMN_NAM SEGMENT_NAME INDEX_NAME CHUNK SEC
---------- ---------- ------------------------- ------------------------- ---------- ---
TEST_TAB TEXT SYS_LOB0006244894C00005$$ SYS_IL0006244894C00005$$ 32768 NO
select event, p1, p2, p3, p1text, p2text, p3text, row_wait_obj#, row_wait_file#, row_wait_block#, row_wait_row#
from v$session where sid = 912;
EVENT P1 P2 P3 P1TEXT P2TEXT P3TEXT ROW_WAIT_OBJ# ROW_WAIT_FILE# ROW_WAIT_BLOCK# ROW_WAIT_ROW#
-------------------- ---------- ---------- ---------- --------------- --------------- --------------- ------------- -------------- --------------- -------------
direct path read 22 5217040 4 file number first dba block cnt 6244897 22 5217040 0
$ > strace -p 2472818
io_submit(0x7f13d15dd000, 1, [{aio_data=0x7f13ca2814f0, aio_lio_opcode=IOCB_CMD_PREAD, aio_fildes=264, aio_buf=0x7f13ca299000, aio_nbytes=32768, aio_offset=36884873216}]) = 1
io_getevents(0x7f13d15dd000, 2, 128, [{data=0x7f13ca6502f8, obj=0x7f13ca6502f8, res=32768, res2=0}], {tv_sec=0, tv_nsec=0}) = 1
io_getevents(0x7f13d15dd000, 1, 128, [{data=0x7f13ca2814f0, obj=0x7f13ca2814f0, res=32768, res2=0}], {tv_sec=600, tv_nsec=0}) = 1
3 Securefile Test
Now we make one more test with securefile:
--------------------- securefile -----------------------
drop table test_tab purge;
create table test_tab (
id number,
code varchar2(10),
name varchar2(100),
created_date date,
text clob,
constraint test_tab_pk primary key (id)
)
--lob (text) store as basicfile (
lob (text) store as securefile test_tab_sf_text (
--compress medium
enable storage in row
-- chunk 32768 -- 8192 (default), 32768=4*8192, no effect for securefile
)
partition by range (created_date)
(
partition test_tab_2026 values less than (maxvalue)
);
create index test_tab#code on test_tab (code);
create index test_tab#created_date on test_tab (created_date) local;
-- Fill table with 1000 rows, each contain one 8 MB Clob
exec test_tab_fill(1000, 1024*8);
exec dbms_stats.gather_table_stats(user, 'TEST_TAB', cascade => true);
select round(sum(length(text)/1024/1024)) mb, count(*), round(sum(length(text))/count(*)/1024) avg_len_kb from test_tab;
MB COUNT(*) AVG_LEN_KB
---------- ---------- ----------
8000 1000 8192
alter session set max_dump_file_size=unlimited;
alter session set tracefile_identifier = 'test_sec';
alter session set events '10046 trace name context forever, level 12';
alter table test_tab
split partition test_tab_2026 at (date'2025-12-31')
into (partition test_tab_2025,
partition test_tab_2026)
update indexes --parallel 8
;
Elapsed: 00:01:18.87
alter session set events '10046 trace name context off';
Her SQL trace:
********************************************************************************
alter table test_tab
split partition test_tab_2026 at (date'2025-12-31')
into (partition test_tab_2025,
partition test_tab_2026)
update indexes --parallel 8
call count cpu elapsed disk query current rows
------- ------ -------- ---------- ---------- ---------- ---------- ----------
Parse 1 0.00 0.00 0 0 0 0
Execute 1 21.50 78.46 2082018 44947 103278 1000
Fetch 0 0.00 0.00 0 0 0 0
------- ------ -------- ---------- ---------- ---------- ---------- ----------
total 2 21.51 78.47 2082018 44947 103278 1000
Misses in library cache during parse: 1
Optimizer mode: ALL_ROWS
Parsing user id: 49
Number of plan statistics captured: 1
Rows (1st) Rows (avg) Rows (max) Row Source Operation
---------- ---------- ---------- ---------------------------------------------------
0 0 0 LOAD AS SELECT TEST_TAB (cr=44142 pr=2082015 pw=2082024 time=78415081 us starts=1)
1000 1000 1000 PARTITION RANGE SINGLE PARTITION: 1 1 (cr=30 pr=0 pw=0 time=9530 us starts=1 cost=10 size=255000 card=1000)
1000 1000 1000 TABLE ACCESS FULL TEST_TAB PARTITION: 1 1 (cr=30 pr=0 pw=0 time=9027 us starts=1 cost=10 size=255000 card=1000)
Elapsed times include waiting on following events:
Event waited on Times Max. Wait Total Waited
---------------------------------------- Waited ---------- ------------
direct path read 5899 0.31 54.81
local write wait 664 0.19 0.42
reliable message 10 0.00 0.00
enq: CR - block range reuse ckpt 6 0.00 0.00
db file sequential read 66 0.02 0.04
direct path write 71 0.02 0.24
control file sequential read 480 0.03 0.21
datafile move cleanup during resize 24 0.00 0.00
Disk file operations I/O 72 0.03 0.09
Data file init write 42 0.02 0.24
direct path sync 24 0.00 0.00
db file single write 24 0.00 0.00
control file parallel write 72 0.00 0.06
DLM cross inst call completion 24 0.00 0.01
enq: RO - fast object reuse 4 0.01 0.01
PGA memory operation 1 0.00 0.00
SQL*Net message to client 1 0.00 0.00
SQL*Net message from client 1 0.01 0.01
********************************************************************************
select table_name, column_name, segment_name, index_name, chunk, securefile from dba_lobs where table_name = 'TEST_TAB';
TABLE_NAME COLUMN_NAM SEGMENT_NAME INDEX_NAME CHUNK SECUREFILE
---------- ---------- ------------------------- ------------------------- ---------- ---------------
TEST_TAB TEXT TEST_TAB_SF_TEXT SYS_IL0006244918C00005$$ 8192 YES
select sample_time, event, p1, p2, p3, p1text, p2text, p3text, current_obj#, current_file#, current_block#, current_row#
from v$active_session_history t
where sample_time > sysdate-5/1440
and session_id = 912
and event in ('direct path read', 'direct path write')
order by t.sample_time;
SAMPLE_TIME EVENT P1 P2 P3 P1TEXT P2TEXT P3TEXT CURRENT_OBJ# CURRENT_FILE# CURRENT_BLOCK# CURRENT_ROW#
-------------------- -------------------- ---------- ---------- ---------- --------------- --------------- --------------- ------------ ------------- -------------- ------------
03-JUL-2026 14:48:23 direct path read 22 5607312 128 file number first dba block cnt 6244921 22 5607312 0
03-JUL-2026 14:48:24 direct path read 22 4057350 128 file number first dba block cnt 6244921 22 4057350 0
03-JUL-2026 14:48:25 direct path read 22 4086036 128 file number first dba block cnt 6244921 22 4086036 0
$ > strace -p 2472818
io_submit(0x7f13d15dd000, 1, [{aio_data=0x681ca000, aio_lio_opcode=IOCB_CMD_PREAD, aio_fildes=264, aio_buf=0x16f400000, aio_nbytes=1048576, aio_offset=32394772480}]) = 1
io_submit(0x7f13d15dd000, 1, [{aio_data=0x8ea63e48, aio_lio_opcode=IOCB_CMD_PREAD, aio_fildes=264, aio_buf=0x16f300000, aio_nbytes=1048576, aio_offset=32395821056}]) = 1
io_submit(0x7f13d15dd000, 1, [{aio_data=0x8c41ddb0, aio_lio_opcode=IOCB_CMD_PREAD, aio_fildes=264, aio_buf=0x16f200000, aio_nbytes=1048576, aio_offset=32396869632}]) = 1
io_submit(0x7f13d15dd000, 1, [{aio_data=0x66503b30, aio_lio_opcode=IOCB_CMD_PREAD, aio_fildes=264, aio_buf=0x16fa00000, aio_nbytes=1048576, aio_offset=32397918208}]) = 1
