[Oracle运维工程师手记系列]如何从trace 文件，判断是否执行了并行
客户说，明明指定了并行的hint,OEM 却报说没有并行，并且提供了画面。
客户的SQL文长这样:
INSERT/*+ parallel(4) */ INTO TAB001_WORK SELECT/*+ FULL(USR002) */
USR002.IM_PRO_CD, USR002.IM_NO, USR002.PS_DATE, USR002.YY_MM,
到底如何呢，口说无凭，还是来作一次并行trace吧。
SQL> alter session set tracefile_identifier='test1';
SQL> alter session set events 'trace[px_messaging] disk highest';
SQL> alter session set events 'trace[px_control] disk highest';
SQL> alter session set events 'trace[px_scheduler] disk high';
SQL> alter session set events 'trace[sql_compiler.*] disk medium';
SQL> 执行 出现问题的 SQL 文
SQL> exit;
这样，会一次性地得到几个trace 文件。
MBL12_ora_92961_test1.trc
MBL11_p000_33866_test1.trc
MBL11_p001_32473_test1.trc
MBL11_p002_32741_test1.trc
......
第一个文件: 是 QC 文件。其他的应当是它生成的 Parallel 文件。
应当主要从QC 文件着手进行分析:
**************************
Automatic degree of parallelism (ADOP)
**************************
kkfdtParallel: parallel is possible (no statement type restrictions)
kkfdIsAutoDopSupported:Yes, ctxoct:2, boostrap SQL?:FALSE, remote?:FALSE, stmt?:FALSE.
Automatic degree of parallelism is enabled for this statement in hint mode.
kkopqSetForceParallelProperties: Hint:yes
Query: compute:no forced:yes forceDop:4
DDLDML : compute:no forced:yes forceDop:4
kkopqSetDopReason: Reason why we chose this DOP is: hint. <<<<< 此处是说明通过hint ,认识到要执行 parallel 处理。
hint forces parallelism with dop=4
下面，内容是这样的：
2018-04-24 09:36:23.759351*:PX_Messaging:kxfp.c@18652:kxfpclinfo():
load balancing disabled due to single PQ running (non-QA mode)on local inst 2 (total # inst: 2).
(default: 0) inst target is 40
number of active slaves on the instance: 0,
number of active slaves but available to use: 0 <<<<< 一开始的时候，没有可用的资源
接下来，可以看到，正尝试着去获得slave 进程：
2018-04-24 09:36:23.760357*:PX_Messaging:kxfp.c@11588:kxfpg1srv(): trying to get slave P000 on instance 1 for q=0x80d9eac90
2018-04-24 09:36:23.760927*:PX_Messaging:kxfp.c@11631:kxfpg1srv(): slave P000 is remote (inst=1) 2018-04-24 09:36:23.760927*:PX_Messaging:kxfp.c@11669:kxfpg1srv(): - acquired dp=(nil)
2018-04-24 09:36:23.760927*:PX_Messaging:kxfp.c@11104:kxfpg1sg(): Got It. 1 so far.
2018-04-24 09:36:23.760927*:PX_Messaging:kxfp.c@11588:kxfpg1srv(): trying to get slave P001 on instance 1 for q=0x80d9eac90
2018-04-24 09:36:23.760927*:PX_Messaging:kxfp.c@11631:kxfpg1srv(): slave P001 is remote (inst=1) 2018-04-24 09:36:23.760927*:PX_Messaging:kxfp.c@11669:kxfpg1srv(): - acquired dp=(nil)
2018-04-24 09:36:23.760927*:PX_Messaging:kxfp.c@11104:kxfpg1sg(): Got It. 2 so far.
jStart=0 jEnd=60 jIncr=1 isGV=0 i=1 instno=2 kxfpilthno=2
2018-04-24 09:36:23.760927*:PX_Messaging:kxfp.c@11588:kxfpg1srv(): trying to get slave P000 on instance 2 for q=0x80d9eac90
2018-04-24 09:36:23.760927*:PX_Messaging:kxfp.c@11686:kxfpg1srv(): slave P000 is local
2018-04-24 09:36:23.760927*:PX_Messaging:kxfp.c@11716:kxfpg1srv(): found dp=0x85a9c9c68 flg=18
2018-04-24 09:36:23.760927*:PX_Messaging:kxfp.c@11747:kxfpg1srv(): local slave already started.. sid = 0, iid = 2
2018-04-24 09:36:23.760927*:PX_Messaging:kxfp.c@11104:kxfpg1sg(): Got It. 3 so far.
2018-04-24 09:36:23.760927*:PX_Messaging:kxfp.c@11588:kxfpg1srv(): trying to get slave P001 on instance 2 for q=0x80d9eac90
2018-04-24 09:36:23.761444*:PX_Messaging:kxfp.c@11686:kxfpg1srv(): slave P001 is local
2018-04-24 09:36:23.761444*:PX_Messaging:kxfp.c@11716:kxfpg1srv(): found dp=0x85a9c9cf8 flg=18
2018-04-24 09:36:23.761444*:PX_Messaging:kxfp.c@11747:kxfpg1srv(): local slave already started.. sid = 1, iid = 2
2018-04-24 09:36:23.761444*:PX_Messaging:kxfp.c@11104:kxfpg1sg(): Got It. 4 so far.
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< 上面的信息表明开始试着去获取并行slave 进程，并渐次取得成功
再往下看，可以看到确实获得了想要的那些个并行进程：
2018-04-24 09:36:23.774484*:PX_Messaging:kxfp.c@11536:kxfpg1sg():
got 4 servers (sync), errors=0x0 returning <<<<<<<<<<<<<<<<<<<<<<<<< 从这里也可以看得出来，确实取得了4个并行进程
Acquired 8 slaves on 2 instances avg height=2 #set=2 qser=14923778 <<<<<<<< 估计因为有两个 set 的缘故，故此得到了8个并行进程
P000 inst 1 spid 33866
P001 inst 1 spid 32473
P000 inst 2 spid 81205
P001 inst 2 spid 88210
P002 inst 1 spid 32741
P003 inst 1 spid 38214
P002 inst 2 spid 82324
P003 inst 2 spid 88129
2018-04-24 09:36:23.774484*:PX_Messaging:kxfp.c@10729:kxfpgsg():
Instance(servers):
inst=1 #slvs=4
inst=2 #slvs=4
接下来，可以看到 QC 正在和 各个Parallel进程 set 进行通信：
QC enabled kgl EXPRESS bit on slave for SQL:
----- Current SQL Statement for this session (sql_id=cay1xmzv2mtyz) -----
INSERT/*+ parallel(4) */ INTO TAB001_WORK SELECT/*+ FULL(USR002) */ USR002.IM_PRO_CD, USR002.IM_NO, USR002.PS_DATE, USR002.YY_MM, USR002.YEAR,
.....
size: 40 aligned: 40 total:9104 rem:7008 to: 4
Sending parse to slave set 1: <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< QC 和 set 1 进行通信
User sqllen sent from QC = 7317
......
2018-04-24 09:36:23.793626*:PX_Messaging:kxfp.c@5138:kxfpqrsnd():
Deliver to qref=0x85e94cd8 (points at 2.-1) msg=0x7bff77fd0 flg=0x1
qref: qrser=14923778 qrseq=5 qrflg=0x1 fmh=0x2 state=00010
msg: mhser=14923778 mhseq=6 mhst=3 mhty=6 from=0x85e974c8
qref flow mode now 0x1
Receiver qref ending state=11010
after rsnd/qsnd for qref=0x85e974c8 state=10011 slm=0 bn=1 b0=0x7bff4dfb8 b1=(nil)
after buf swap qref=0x85e974c8 state=00000 slm=0 bn=1 b0=(nil) b1=0x7bff4dfb8
sender qref ending state=00000
kxfxcp1 [ 50/ 0]
Sending parse to nprocs:4 slave_set:2 <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< QC 和 set 2 进行通信
2018-04-24 09:36:23.793843*:PX_Messaging:kxfp.c@4131:kxfprigeb():
Get buffer on q=0x80d9eac90 qref=0x85e9dbf0 server=1.2 flags0x0 qstat=10000
Got buffer on qref=0x85e9dbf0 qrser=14923778 qrseq=4 mh=0x7bff59fb8 fmh=a1 qstat=10011
......
QC enabled kgl EXPRESS bit on slave for SQL:
----- Current SQL Statement for this session (sql_id=cay1xmzv2mtyz) -----
INSERT/*+ parallel(4) */ INTO TAB001_WORK SELECT/*+ FULL(USR002) */ USR002.IM_PRO_CD,
......
61394 行目：
QC sends top nobj#:-1 ikc:0 #parts:1048576 flg:0
kxfxpnd [ 60/ 0]
size: 40 aligned: 40 total:8984 rem:7128 to: 4
kxfxpoeobjv:65535, kxfxpoPMax:1048576, kxfxponobj:-1
QC sends top nobj#:-1 ikc:0 #parts:1048576 flg:0
kxfxpnd [ 60/ 0]
size: 40 aligned: 40 total:9024 rem:7088 to: 4
kxfxpoeobjv:65535, kxfxpoPMax:1048576, kxfxponobj:-1
QC sends top nobj#:-1 ikc:0 #parts:1048576 flg:0
kxfxpnd [ 60/ 0]
size: 40 aligned: 40 total:9064 rem:7048 to: 4
kxfxpoeobjv:65535, kxfxpoPMax:1048576, kxfxponobj:-1
QC sends top nobj#:-1 ikc:0 #parts:1048576 flg:0
kxfxpnd [ 60/ 0]
size: 40 aligned: 40 total:9104 rem:7008 to: 4
到最后，可以看到QC与Slave进程的通信结束了, Slave进程被释放：
2018-04-24 09:36:26.599729*:PX_Messaging:kxfp.c@21306:kxfpIDNDeregister():
removing link for qc 0x80d9eac90 sess 423 <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< QC 与 Slave 进程的通信结束
removing link 0x87544b030 for qc 0x80d9eac90 on list 7
......
2018-04-24 09:36:26.608002*:PX_Messaging:kxfp.c@6477:kxfpGatherSlaveStats(begin):
q=0x80d9eac90 qser=14923778
2018-04-24 09:36:26.608002*:PX_Messaging:kxfp.c@6572:kxfpGatherSlaveStats(end):
2018-04-24 09:36:26.608002*:PX_Messaging:kxfp.c@3102:kxfpqsod_qc_sod(): all slaves released qser=14923778 <<<<<<<<<<<<< 所有的 Slave 进程工作结束，被回收
从上面就可以看到确实是完成了并行的工作。
但是，为什么 OEM 报 没有并行，而是单进程执行? 初步估计是OEM 显示错了。进一步的分析就要移交给 OEM 团队通过 OEM 观点进行分析了。