一、简介
本文主要记录一次主机io流量过高的oracle告警。通过linux命令iotop快速分析主机上io占用大的进程，随后通过oracle上v$process和v$\session视图分析出io占用大的oracle会话信息。
二、iotop分析主机io信息
iotop -oPa
结果如下：
PID PRIO USER DISK READ> DISK WRITE SWAPIN IO COMMAND
78491 be/4 ******** 75.66 G 996.00 K 0.00 % 0.24 % *************
68302 be/4 ******** 75.09 G 996.00 K 0.00 % 0.22 % *************
74078 be/4 ******** 74.77 G 996.00 K 0.00 % 0.21 % *************
66484 be/4 ******** 74.73 G 1992.00 K 0.00 % 0.58 % *************
76430 be/4 ******** 73.92 G 996.00 K 0.00 % 0.23 % *************
73801 be/4 ******** 73.20 G 1992.00 K 0.00 % 0.40 % *************
663 be/4 ******** 29.22 G 0.00 B 0.00 % 51.55 % *************
91884 be/4 ******** 709.26 M 1412.13 M 0.00 % 1.61 % *************
62789 be/4 ******** 660.98 M 0.00 B 0.00 % 59.23 % *************
54332 be/4 ******** 511.54 M 0.00 B 0.00 % 3.26 % *************
52662 be/4 ******** 137.42 M 0.00 B 0.00 % 0.34 % *************
66191 be/4 ******** 30.80 M 0.00 B 0.00 % 80.65 % *************
19729 be/4 ******** 23.02 M 69.38 M 0.00 % 4.22 % *************
16375 be/4 ******** 10.86 M 0.00 B 0.00 % 2.85 % *************
显然，进程id为78491、68302、74078、66484、76430和73801的进程占用io较高。
三、v$process和v$session分析数据库会话信息
查询命令
SELECT SID
|| ','
|| SERIAL# SID#,
MACHINE,
USERNAME,
EVENT,
STATE,
WAIT_TIME_MICRO,
BLOCKING_INSTANCE
|| ( CASE
WHEN BLOCKING_INSTANCE IS NULL THEN NULL
ELSE ','
END )
|| BLOCKING_SESSION BL_SESS,
FINAL_BLOCKING_INSTANCE
|| ( CASE
WHEN FINAL_BLOCKING_INSTANCE IS NULL THEN NULL
ELSE ','
END )
|| FINAL_BLOCKING_SESSION FI_BL_SESS,
FINAL_BLOCKING_SESSION_STATUS,
STATUS,
COMMAND,
SQL_ID,
SQL_CHILD_NUMBER,
PREV_SQL_ID,
PREV_CHILD_NUMBER,
WAIT_CLASS,
WAIT_TIME,
SECONDS_IN_WAIT,
TIME_REMAINING_MICRO,
TIME_SINCE_LAST_WAIT_MICRO,
P1,
P1RAW,
P2,
P2RAW,
P3,
P3RAW,
PADDR,
TADDR,
SADDR,
OSUSER,
PROCESS,
CREATOR_ADDR,
AUDSID,
ROW_WAIT_OBJ#,
ROW_WAIT_FILE#,
ROW_WAIT_BLOCK#,
ROW_WAIT_ROW#,
PROGRAM,
COMMAND,
PLSQL_ENTRY_OBJECT_ID,
PLSQL_ENTRY_SUBPROGRAM_ID,
PLSQL_OBJECT_ID,
PLSQL_SUBPROGRAM_ID,
SQL_EXEC_START,
LOGON_TIME,
CLIENT_IDENTIFIER,
SERVICE_NAME,
RESOURCE_CONSUMER_GROUP
FROM V$SESSION
WHERE paddr IN (SELECT addr
FROM v$process
WHERE spid = &spid);
查询结果如下：
SQL> SELECT SID||','||SERIAL# SID#,MACHINE,USERNAME,EVENT,STATE,WAIT_TIME_MICRO,BLOCKING_INSTANCE||(CASE WHEN BLOCKING_INSTANCE IS NULL THEN NULL ELSE ',' END)||BLOCKING_SESSION BL_SESS,FINAL_BLOCKING_INSTANCE||(CASE WHEN FINAL_BLOCKING_INSTANCE IS NULL THEN NULL ELSE ',' END)||FINAL_BLOCKING_SESSION FI_BL_SESS,FINAL_BLOCKING_SESSION_STATUS,STATUS,COMMAND,SQL_ID,SQL_CHILD_NUMBER,PREV_SQL_ID,PREV_CHILD_NUMBER,WAIT_CLASS,WAIT_TIME,SECONDS_IN_WAIT,TIME_REMAINING_MICRO,TIME_SINCE_LAST_WAIT_MICRO,P1,P1RAW,P2,P2RAW,P3,P3RAW,PADDR,TADDR,SADDR,OSUSER,PROCESS,CREATOR_ADDR,AUDSID,ROW_WAIT_OBJ#,ROW_WAIT_FILE#,ROW_WAIT_BLOCK#,ROW_WAIT_ROW#,PROGRAM,COMMAND,PLSQL_ENTRY_OBJECT_ID,PLSQL_ENTRY_SUBPROGRAM_ID,PLSQL_OBJECT_ID,PLSQL_SUBPROGRAM_ID,SQL_EXEC_START,LOGON_TIME,CLIENT_IDENTIFIER,SERVICE_NAME,RESOURCE_CONSUMER_GROUP FROM V$SESSION where paddr in (select addr from v$process where spid in (78491,68302,74078,66484,76430,73801));
SID# MACHINE USERNAME EVENT STATE WT_MILLI BL_SESS FI_BL_SE FI_BL_S_S STATUS COMMAND SQL_ID SCH PREV_SQL_ID PCH WAIT_CLASS WAIT_TIME SECONDS_IN_WAIT P1 P1RAW P2 P2RAW P3 P3RAW PADDR TADDR SADDR OSUSER PROCESS CREATOR_ADDR AUDSID ROW_WAIT_OBJ# ROW_WAIT_FILE# ROW_WAIT_BLOCK# ROW_WAIT_ROW# PROGRAM COMMAND PLSQL_ENTRY_OBJECT_ID PLSQL_ENTRY_SUBPROGRAM_ID PLSQL_OBJECT_ID PLSQL_SUBPROGRAM_ID SQL_EXEC_START LOGON_TIME CLIENT_IDENTIFIER SERVICE_NA RESOURCE_CONSUMER_GROUP
------------ ------------------ ------------ ---------------------------- ---------- ------------- -------- -------- ---------- ------ ------- ------------- --- ------------- --- ---------- --------- --------------- ------------------- ---------------- ------------------- ---------------- ------------------- ---------------- ---------------- ---------------- ---------------- ---------- ------------ ---------------- ---------- ------------- -------------- --------------- ------------- -------------------------------- ------- --------------------- ------------------------- --------------- ------------------- ------------------- ------------------- -------------------- ---------- --------------------------------
1551,34255 *********** SYS Backup Restore Throttle slee WAITED KNO 1000073 NOT IN WAI ACTIVE 0 6yu0rb6um4wqm 0 Other 100 2 1551 000000000000060F 34255 00000000000085CF 0 00 00000011356ED348 0000001105ED21B0 oracle 61122 00000011356ED348 4294967295 -1 0 0 0 rman@*********** (TNS V1-V3) 0 9319 303 2019-08-25 19:02:34 SYS$USERS
2702,17483 *********** SYS Backup Restore Throttle slee WAITING 355797 UNKNOWN ACTIVE 0 6yu0rb6um4wqm 0 Other 0 0 2702 0000000000000A8E 17483 000000000000444B 0 00 00000011056F44D8 00000011360C7450 oracle 61122 00000011056F44D8 4294967295 -1 0 0 0 rman@*********** (TNS V1-V3) 0 9319 303 2019-08-25 19:02:56 SYS$USERS
3470,33841 *********** SYS Backup Restore Throttle slee WAITED KNO 1000075 NOT IN WAI ACTIVE 0 6yu0rb6um4wqm 0 Other 100 3 3470 0000000000000D8E 33841 0000000000008431 0 00 00000011457AAAC8 0000001116210B10 oracle 61122 00000011457AAAC8 4294967295 -1 0 0 0 rman@*********** (TNS V1-V3) 0 9319 303 2019-08-25 19:03:18 SYS$USERS
10402,16591 *********** SYS Backup Restore Throttle slee WAITING 0 UNKNOWN ACTIVE 0 6yu0rb6um4wqm 0 Other 0 0 10402 00000000000028A2 16591 00000000000040CF 0 00 00000011457A8958 0000001136DE76D0 oracle 61122 00000011457A8958 4294967295 -1 0 0 0 rman@*********** (TNS V1-V3) 0 9319 303 2019-08-25 19:01:27 SYS$USERS
11172,23095 *********** SYS Backup Restore Throttle slee WAITING 393751 UNKNOWN ACTIVE 0 6yu0rb6um4wqm 0 Other 0 0 11172 0000000000002BA4 23095 0000000000005A37 0 00 00000011356EC290 0000001136F37710 oracle 61122 00000011356EC290 4294967295 -1 0 0 0 rman@*********** (TNS V1-V3) 0 9319 303 2019-08-25 19:02:11 SYS$USERS
11945,64993 *********** SYS Backup Restore Throttle slee WAITING 510444 UNKNOWN ACTIVE 0 6yu0rb6um4wqm 0 Other 0 1 11945 0000000000002EA9 64993 000000000000FDE1 0 00 00000011156D5D70 0000001157068D20 oracle 61122 00000011156D5D70 4294967295 -1 0 0 0 rman@*********** (TNS V1-V3) 0 9319 303 2019-08-25 19:01:49 SYS$USERS
6 rows selected.
由查询结果可知，数据库当前io流量大的主要原因是在做备份，与做备份的同事沟通，确认数据库确实是在做备份，而且开了6个io通道，每个io通道限速200MB/s。可通过以下命令确认是否存在RMAN备份进程
ps -ef | grep rman
四、iotop使用方法
[oracle@dgg-xxxxxxxx-or ~]$ iotop
Netlink error: Operation not permitted (1)
The Linux kernel interfaces that iotop relies on now require root privileges
or the NET_ADMIN capability. This change occurred because a security issue
(CVE-2011-2494) was found that allows leakage of sensitive data across user
boundaries. If you require the ability to run iotop as a non-root user, please
configure sudo to allow you to run iotop as root.
Please do not file bugs on iotop about this.
[oracle@dgg-dggaud10-or ~]$ iotop -h
Usage: /usr/sbin/iotop [OPTIONS]
DISK READ and DISK WRITE are the block I/O bandwidth used during the sampling
period. SWAPIN and IO are the percentages of time the thread spent respectively
while swapping in and waiting on I/O more generally. PRIO is the I/O priority at
which the thread is running (set using the ionice command).
Controls: left and right arrows to change the sorting column, r to invert the
sorting order, o to toggle the --only option, p to toggle the --processes
option, a to toggle the --accumulated option, q to quit, any other key to force
a refresh.
Options:
--version show program's version number and exit
-h, --help show this help message and exit
-o, --only only show processes or threads actually doing I/O
-b, --batch non-interactive mode
-n NUM, --iter=NUM number of iterations before ending [infinite]
-d SEC, --delay=SEC delay between iterations [1 second]
-p PID, --pid=PID processes/threads to monitor [all]
-u USER, --user=USER users to monitor [all]
-P, --processes only show processes, not all threads
-a, --accumulated show accumulated I/O instead of bandwidth
-k, --kilobytes use kilobytes instead of a human friendly unit
-t, --time add a timestamp on each line (implies --batch)
-q, --quiet suppress some lines of header (implies --batch)