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Troubleshooting DB session spin call java function

一天客户问有个SQL执行中好像是hang了,环境oracle 19c RAC,当前的session对应的v$session.event是‘gc current grant 2-way ’, 之前运行都是秒级,现在已经跑了1个小时还未结束,通常看到这个event会怀疑是GC出了问题,然后就走错了路, 下面看一下这个案例。

SQL> select username,sid,sql_id,event,seconds_in_wait,state,last_call_et from v$session where sql_id='0ax014ztkh0r4';

USERNAME          SID SQL_ID        EVENT                                                        SECONDS_IN_WAIT STATE                 LAST_CALL_ET
---------- ---------- ------------- ------------------------------------------------------------ --------------- ------------------- --------------
ANBOB_U1         1651 0ax014ztkh0r4 gc current grant 2-way                                                  3834 WAITED SHORT TIME             3836

SQL> select username,sid,sql_id,event,seconds_in_wait,state,last_call_et,blocking_instance,blocking_session from v$session where sql_id='0ax014ztkh0r4';

USERNAME          SID SQL_ID        EVENT                                                        SECONDS_IN_WAIT STATE                 LAST_CALL_ET BLOCKING_INSTANCE BLOCKING_SESSION
---------- ---------- ------------- ------------------------------------------------------------ --------------- ------------------- -------------- ----------------- ----------------
ANBOB_U1         1651 0ax014ztkh0r4 gc current grant 2-way                                                  3898 WAITED SHORT TIME             3900

v$session 和v$session_wait的event是表示不只是当前的wait event,还有可能是上一个(刚刚完成的)event, 如何判断是否当前正在等待呢?可以查看当state列如果是”WAITING”时. 也可以参考WAIT_TIME列,当值为0时表示会话当前正在等待,同时SECONDS_IN_WAIT列是当前等待所花费的时间,从11g以后不再建议使用此列,用另外两列代替,如wait_time_micro表示等待的时间(以微秒为单位),如果会话当前正在等待中,则此列的值为当前等待中花费的时间,如果会话当前不在等待中,则该值为上一次等待中等待的时间。而对于另一列TIME_REMAINING_MICRO 是估算等待的剩余时间,如果为null 表示当前会话未等待。(不过我觉的这列仅供参考)

上面这个会话当前session.state 是’WAITED SHORT TIME’, 所以该event并不是当前会话的正在等待的event, 如果使用我的ase.sql查看活动会话,会显示ON cpu.

下面分析SQL 使用sql monitor 利器

SQL>  select DBMS_SQLTUNE.REPORT_SQL_MONITOR(sql_id=>'&sql_id',report_level=>'ALL',type=>'text')  from dual; 
Enter value for sql_id: 0ax014ztkh0r4

DBMS_SQLTUNE.REPORT_SQL_MONITOR(SQL_ID=>'0AX014ZTKH0R4',REPORT_LEVEL=>'ALL',TYPE=>'TEXT')
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
SQL Monitoring Report

SQL Text
------------------------------
UPDATE ANBOB_ENCRYPT_20210315 A SET PASSWORD_NEW = JAVA_ENCRY_F(A.ATTR_VALUE) WHERE PROD_INST_ID_1 = :B1

Global Information
------------------------------
 Status                                 :  EXECUTING
 Instance ID                            :  1
 Session                                :  ANBOB_U1 (1651:36742)
 SQL ID                                 :  0ax014ztkh0r4
 SQL Execution ID                       :  16806606
 Execution Started                      :  03/16/2021 14:52:26
 First Refresh Time                     :  03/16/2021 14:52:32
 Last Refresh Time                      :  03/16/2021 15:53:50
 Duration                               :  3685s
 Module/Action                          :  SQL*Plus/-
 Service                                :  xxxxxxxxxxx
 Program                                :  sqlplus@xxx-11fb-g06-sev-r730-02u22 (TNS V1-V
 PLSQL Entry Ids (Object/Subprogram)    :  1081201,1
 PLSQL Current Ids (Object/Subprogram)  :  1081201,1

Binds
========================================================================================================================
| Name | Position |  Type  |                                           Value                                           |
========================================================================================================================
| :B1  |        1 | NUMBER | 925559560                                                                                 |
========================================================================================================================

Global Stats
===================================================
| Elapsed |   Cpu   |  Java   |  Other   | Buffer |
| Time(s) | Time(s) | Time(s) | Waits(s) |  Gets  |
===================================================
|    3686 |    3681 |    3686 |     4.59 |      5 |  #buffer get 5,cpu time 3681s,java time 3686s
===================================================

SQL Plan Monitoring Details (Plan Hash Value=3801314702)
===============================================================================================================================================
| Id   |      Operation      |           Name           |  Rows   | Cost |   Time    | Start  | Execs |   Rows   | Activity | Activity Detail |
|      |                     |                          | (Estim) |      | Active(s) | Active |       | (Actual) |   (%)    |   (# samples)   |
===============================================================================================================================================
|    0 | UPDATE STATEMENT    |                          |         |      |         1 |     +6 |     1 |        0 |          |                 |
|    1 |   UPDATE            | ANBOB_ENCRYPT_20210315   |         |      |      3686 |     +1 |     1 |        0 |   100.00 | Cpu (3672)      |  
| -> 2 |    INDEX RANGE SCAN | ANBOB_ENCRYPT_20210315_1 |       1 |    1 |      3683 |     +6 |     1 |        1 |          |                 |
===============================================================================================================================================

Note:
session 确实已经running了1个多小时,更新1行,buffer gets 5,  时间都记入了Java TIME.

看session call stack

SQL> oradebug short_stack
ksedsts()+426<-ksdxfstk()+58<-ksdxcb()+872<-sspuser()+200<-__sighandler()<-PassWord__encode()+1753<-sjoninvk_jit()+1041<-joevm_joe_run_jit_somersault()+458<-joe_invoke()+1631<-joet_aux_thread_main()+1674<-seoa_note_stack_outside()+34<-joet_thread_main()+64<-sjontlo_initialize()+178<-joe_enter_vm()+1197<-ioei_call_java()+4716<-ioesub_CALL_JAVA()+569<-seoa_note_stack_outside()+34<-ioe_call_java()+292<-jox_invoke_java_()+4133<-kkxmjexe()+1493<-kgmexcb()+56<-kkxmswu()+91<-kgmexwi()+1011<-kgmexec()+1452<-evapls()+1251<-evaopn2()+737<-upderh()+1252<-upduaw()+193<-kdusru()+617<-kauupd()+356<-updrow()+1693<-qerupUpdRow()+725<-qerupFetch()+644<-updaul()+1416<-updThreePhaseExe()+340<-updexe()+443<-opiexe()+11783<-opipls()+2086<-opiodr()+1202<-rpidrus()+198<-skgmstack()+65<-rpidru()+132<-rpiswu2()+541<-rpidrv()+1248<-psddr0()+467<-psdnal()+624<-pevm_EXECC()+306<-pfrinstr_EXECC()+56<-pfrrun_no_tool()+52<-pfrrun()+902<-plsql_run()+752<-peicnt()+282<-kkxexe()+720<-opiexe()+30719<-kpoal8()+2387<-opiodr()+1202<-ttcpip()+1222<-opitsk()+1897<-opiino()+936<-opiodr()+1202<-opidrv()+1094<-sou2o()+165<-opimai_real()+422<-ssthrdmain()+417<-main()+256<-__libc_start_main()+245 SQL> oradebug short_stack
ksedsts()+426<-ksdxfstk()+58<-ksdxcb()+872<-sspuser()+200<-__sighandler()<-PassWord__encode()+2131<-sjoninvk_jit()+1041<-joevm_joe_run_jit_somersault()+458<-joe_invoke()+1631<-joet_aux_thread_main()+1674<-seoa_note_stack_outside()+34<-joet_thread_main()+64<-sjontlo_initialize()+178<-joe_enter_vm()+1197<-ioei_call_java()+4716<-ioesub_CALL_JAVA()+569<-seoa_note_stack_outside()+34<-ioe_call_java()+292<-jox_invoke_java_()+4133<-kkxmjexe()+1493<-kgmexcb()+56<-kkxmswu()+91<-kgmexwi()+1011<-kgmexec()+1452<-evapls()+1251<-evaopn2()+737<-upderh()+1252<-upduaw()+193<-kdusru()+617<-kauupd()+356<-updrow()+1693<-qerupUpdRow()+725<-qerupFetch()+644<-updaul()+1416<-updThreePhaseExe()+340<-updexe()+443<-opiexe()+11783<-opipls()+2086<-opiodr()+1202<-rpidrus()+198<-skgmstack()+65<-rpidru()+132<-rpiswu2()+541<-rpidrv()+1248<-psddr0()+467<-psdnal()+624<-pevm_EXECC()+306<-pfrinstr_EXECC()+56<-pfrrun_no_tool()+52<-pfrrun()+902<-plsql_run()+752<-peicnt()+282<-kkxexe()+720<-opiexe()+30719<-kpoal8()+2387<-opiodr()+1202<-ttcpip()+1222<-opitsk()+1897<-opiino()+936<-opiodr()+1202<-opidrv()+1094<-sou2o()+165<-opimai_real()+422<-ssthrdmain()+417<-main()+256<-__libc_start_main()+245

因为当前的SQL正在执行java代码部分,说明该存储过程有java语言,需要排查java代码 。

SQL> @ddl ANBOB_U1.JAVA_ENCRY_F
PL/SQL procedure successfully completed.

DBMS_METADATA.GET_DDL(OBJECT_TYPE,OBJECT_NAME,OWNER)
------------------------------------------------------------------------------------------------------
  CREATE OR REPLACE EDITIONABLE FUNCTION "ANBOB_U1"."JAVA_ENCRY_F" (code VARCHAR2)
RETURN VARCHAR2
AS LANGUAGE JAVA
    NAME 'PassWord.encode(java.lang.String) return java.lang.String';
/

再继续分析JAVA 代码部分发现,对应的表中有一条记录,处理进入列循环, while(true) { if xxx } 判断出了问题。

所以到此能明确是因为当前会话执行的SQL,使用了java function, 因为java程序代码缺陷导致SQL一直处理spin(无限循环中). 对于这类问题我个人觉的是程序设计问题,为什么一个加密操作又是java又是db?如果是我,我想要么1,加密在程序中完成,计算后的值存入DB;2,完全使用数据库的加密,如使用dbms_crypto等内置package完成。

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