[20181109]12cR2 的pre_page_sga参数.txt

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[20181109]12cR2 的pre_page_sga参数.txt --//12CR2改变了参数pre_page_sga设置为True.设置为true有好处也有缺点. --//先看看官方的定义: http://docs.oracle.com/cd/E11882_01/server.112/e40402/initparams201.htm#REFRN10174 PRE_PAGE_SGA determines whether Oracle reads the entire SGA into memory at instance startup. Operating system page table entries are then prebuilt for each page of the SGA. This setting can increase the amount of time necessary for instance startup, but it is likely to decrease the amount of time necessary for Oracle to reach its full performance capacity after startup. Note: This setting does not prevent your operating system from paging or swapping the SGA after it is initially read into memory. PRE_PAGE_SGA can increase the process startup duration, because every process that starts must access every page in the SGA. The cost of this strategy is fixed; however, you might simply determine that 20,000 pages must be touched every time a process starts. This approach can be useful with some applications, but not with all applications. Overhead can be significant if your system frequently creates and destroys processes by, for example, continually logging on and logging off. The advantage that PRE_PAGE_SGA can afford depends on page size. For example, if the SGA is 80 MB in size and the page size is 4 KB, then 20,000 pages must be touched to refresh the SGA (80,000/4 = 20,000). If the system permits you to set a 4 MB page size, then only 20 pages must be touched to refresh the SGA (80,000/4,000 = 20). The page size is operating system-specific and generally cannot be changed. Some operating systems, however, have a special implementation for shared memory whereby you can change the page size. --//可以发现使用PRE_PAGE_SGA=true,仅仅在启动是读整个SGA进入内存,如果你设置很大,现在的服务器内存上几百G很正常,启动就慢很多, --//但是能很快达到最佳性能.但是它并不能避免交换使用. --//如果你仔细读后面的信息,可以发现PRE_PAGE_SGA=true的情况设置使用hugepages非常必要. --//这也是我为什么强调安装oracle必须配置hugepags作为必要的步骤,现在许多安装人员基本不做,而业务开展以后要改也带来不必要的 --//麻烦,毕竟要停业务. 1.环境: SQL> select BANNER_FULL from v$version; BANNER_FULL -------------------------------------------------------------------------------- Oracle Database 18c Enterprise Edition Release 18.0.0.0.0 - Production Version 18.3.0.0.0 --//办公环境没有12c,那18c来说明问题一样的. SQL> show pdbs CON_ID CON_NAME OPEN MODE RESTRICTED ------ -------- ---------- ---------- 2 PDB$SEED READ ONLY NO 3 ORCL READ WRITE NO SQL> show parameter pre_page_sga NAME TYPE VALUE ------------- ----------- ------------------------------ pre_page_sga boolean TRUE SQL> show spparameter pre_page_sga SID NAME TYPE VALUE -------- ----------------------------- ----------- ---------------------------- * pre_page_sga boolean --//参数pre_page_sga没有写入spfile参数文件,12CR2以上缺省设置为True.oracle 之所以这样设置主要考虑PDB的原因(我个人人为) 2.看看内存使用情况: # cat /proc/meminfo | grep -i page AnonPages: 2973340 kB PageTables: 803364 kB AnonHugePages: 0 kB HugePages_Total: 0 HugePages_Free: 0 HugePages_Rsvd: 0 HugePages_Surp: 0 Hugepagesize: 2048 kB --//页面表消耗800M. # ps -ef | grep orclcd[b]|wc 85 684 5753 --//仅仅85个进程. # top -u oracle --//按F,移动到RES列,选择s,改变排序模式.这样按照RES排序. top - 08:58:20 up 70 days, 5:06, 3 users, load average: 1.02, 1.04, 1.05 Tasks: 541 total, 1 running, 540 sleeping, 0 stopped, 0 zombie %Cpu(s): 0.2 us, 0.1 sy, 0.0 ni, 99.7 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st KiB Mem : 65709508 total, 8128052 free, 6214192 used, 51367264 buff/cache KiB Swap: 16773116 total, 16773116 free, 0 used. 30169176 avail Mem PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 12970 oracle 20 0 29.2g 11.3g 11.2g S 0.0 18.0 12:10.07 ora_dbw0_orclcd 14369 oracle 20 0 29.2g 3.2g 3.1g S 0.0 5.1 3:24.60 ora_w00b_orclcd 13094 oracle 20 0 29.3g 3.0g 2.9g S 0.0 4.7 4:29.54 ora_w003_orclcd 14420 oracle 20 0 29.2g 2.6g 2.5g S 0.0 4.1 4:17.85 ora_w00f_orclcd 13065 oracle 20 0 29.2g 2.2g 2.2g S 0.0 3.6 20:24.95 ora_p002_orclcd 13067 oracle 20 0 29.2g 2.2g 2.1g S 0.0 3.5 21:26.00 ora_p003_orclcd 14333 oracle 20 0 29.2g 2.1g 2.0g S 0.0 3.3 2:26.60 ora_w005_orclcd 14342 oracle 20 0 29.2g 2.1g 2.0g S 0.0 3.3 2:27.30 ora_w007_orclcd 14365 oracle 20 0 29.2g 2.0g 1.9g S 0.0 3.2 2:28.03 ora_w00a_orclcd 14415 oracle 20 0 29.2g 1.9g 1.8g S 0.0 3.0 2:12.27 ora_w00e_orclcd 12986 oracle 20 0 29.2g 1.9g 1.8g S 0.0 3.0 2:56.72 ora_w000_orclcd 13308 oracle 20 0 29.2g 1.8g 1.8g S 0.0 2.9 110:41.60 ora_cjq0_orclcd 13061 oracle 20 0 29.2g 1.8g 1.7g S 0.0 2.8 24:00.66 ora_p000_orclcd 14360 oracle 20 0 29.2g 1.8g 1.7g S 0.0 2.8 2:16.13 ora_w009_orclcd 13063 oracle 20 0 29.3g 1.7g 1.6g S 0.0 2.7 23:02.60 ora_p001_orclcd 14410 oracle 20 0 29.2g 1.6g 1.5g S 0.0 2.5 1:45.68 ora_w00d_orclcd 14337 oracle 20 0 29.2g 1.6g 1.5g S 0.0 2.5 2:59.62 ora_w006_orclcd 12948 oracle 20 0 29.1g 1.5g 1.5g S 0.0 2.4 1:33.42 ora_mman_orclcd 13051 oracle 20 0 29.2g 1.4g 1.4g S 0.0 2.2 30:11.14 ora_imco_orclcd 14403 oracle 20 0 29.2g 1.3g 1.2g S 0.0 2.0 2:07.15 ora_w00c_orclcd 13000 oracle 20 0 29.2g 1.2g 1.2g S 0.0 2.0 25:06.94 ora_mmon_orclcd 13073 oracle 20 0 29.2g 1.1g 1.0g S 0.0 1.7 5:34.12 ora_p006_orclcd 13075 oracle 20 0 29.1g 1.1g 1.0g S 0.0 1.7 5:35.03 ora_p007_orclcd 13099 oracle 20 0 29.2g 1.0g 1.0g S 0.0 1.6 1:24.58 ora_w004_orclcd ... --//你可以发现一些oracle相关进程RES占用很大的内存. --//贴一个我们生产系统(exadata的情况): pre_page_sga=false. # cat /proc/meminfo | grep -i page AnonPages: 22546648 kB PageTables: 1593420 kB HugePages_Total: 78600 HugePages_Free: 3961 HugePages_Rsvd: 3954 HugePages_Surp: 0 Hugepagesize: 2048 kB --//页面表仅仅消耗1.6G. # ps -ef | grep -i oracled[b]|wc 3648 32832 266538 --//3648个进程. top - 09:04:59 up 1429 days, 6:40, 1 user, load average: 4.18, 3.99, 3.64 Tasks: 3963 total, 4 running, 3959 sleeping, 0 stopped, 0 zombie Cpu(s): 20.7%us, 5.6%sy, 0.0%ni, 73.1%id, 0.0%wa, 0.0%hi, 0.6%si, 0.0%st Mem: 264235388k total, 244039764k used, 20195624k free, 9676076k buffers Swap: 25165820k total, 0k used, 25165820k free, 33019892k cached PID PPID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ RUSER UID GROUP TTY P SWAP TIME CODE DATA nFLT nDRT WCHAN Flags COMMAND 112340 12166 oracle 20 0 951m 499m 12m S 0.0 0.2 1348:50 oracle 1001 oinstall ? 20 451m 22,28 36 857m 0 0 futex_wai ..4.2... /u01/app/oracle/product/agent12c/core/12.1.0.4.0/jdk/bin/java -Xmx223M -XX:MaxPerm 25209 1 oracle 20 0 76.1g 121m 21m S 0.0 0.0 39:38.45 oracle 1001 asmadmin ? 23 76g 39:38 185m 6076 0 0 semtimedo ..4.2... ora_arc9_dbcn1 24016 1 oracle 20 0 76.1g 112m 17m S 0.9 0.0 28805:22 oracle 1001 asmadmin ? 3 75g 480,05 185m 3564 4 0 poll_sche ..4.2... ora_dia0_dbcn1 25199 1 oracle 20 0 76.1g 110m 21m S 0.0 0.0 39:52.84 oracle 1001 asmadmin ? 23 76g 39:52 185m 6168 0 0 semtimedo ..4.2... ora_arc4_dbcn1 25203 1 oracle 20 0 76.1g 110m 21m S 0.0 0.0 39:15.27 oracle 1001 asmadmin ? 23 76g 39:15 185m 6140 0 0 semtimedo ..4.2... ora_arc6_dbcn1 25201 1 oracle 20 0 76.1g 110m 21m S 0.0 0.0 78:29.38 oracle 1001 asmadmin ? 12 76g 78:29 185m 5372 0 0 semtimedo ..4.2... ora_arc5_dbcn1 25205 1 oracle 20 0 76.1g 109m 21m S 0.0 0.0 40:12.35 oracle 1001 asmadmin ? 9 76g 40:12 185m 6152 0 0 semtimedo ..4.2... ora_arc7_dbcn1 25207 1 oracle 20 0 76.1g 109m 21m S 0.0 0.0 40:05.73 oracle 1001 asmadmin ? 20 76g 40:05 185m 6120 0 0 semtimedo ..4.2... ora_arc8_dbcn1 25197 1 oracle 20 0 76.1g 109m 21m S 0.0 0.0 40:26.04 oracle 1001 asmadmin ? 23 76g 40:26 185m 6120 0 0 semtimedo ..4.2... ora_arc3_dbcn1 25191 1 oracle 20 0 76.1g 108m 21m S 0.0 0.0 38:48.21 oracle 1001 asmadmin ? 3 76g 38:48 185m 6096 8 0 semtimedo ..4.2... ora_arc0_dbcn1 25193 1 oracle 20 0 76.1g 108m 21m S 0.0 0.0 39:19.44 oracle 1001 asmadmin ? 6 76g 39:19 185m 6068 0 0 semtimedo ..4.2... ora_arc1_dbcn1 28227 1 oracle 20 0 76.1g 107m 20m S 0.0 0.0 27:07.26 oracle 1001 asmadmin ? 19 76g 27:07 185m 5112 0 0 semtimedo ..4.2... ora_arc7_dben1 28225 1 oracle 20 0 76.1g 105m 20m S 0.0 0.0 27:03.77 oracle 1001 asmadmin ? 5 75g 27:03 185m 4988 0 0 semtimedo ..4.2... ora_arc6_dben1 28213 1 oracle 20 0 76.1g 104m 20m S 0.0 0.0 27:05.39 oracle 1001 asmadmin ? 9 76g 27:05 185m 4984 0 0 semtimedo ..4.2... ora_arc0_dben1 28229 1 oracle 20 0 76.1g 100m 21m S 0.0 0.0 27:14.12 oracle 1001 asmadmin ? 17 76g 27:14 185m 4992 0 0 semtimedo ..4.2... ora_arc8_dben1 28221 1 oracle 20 0 76.1g 98m 21m S 0.0 0.0 27:20.46 oracle 1001 asmadmin ? 3 76g 27:20 185m 5060 0 0 semtimedo ..4.2... ora_arc4_dben1 28231 1 oracle 20 0 76.1g 96m 20m S 0.0 0.0 27:05.01 oracle 1001 asmadmin ? 9 76g 27:05 185m 4992 0 0 semtimedo ..4.2... ora_arc9_dben1 28223 1 oracle 20 0 76.1g 94m 21m S 0.0 0.0 27:03.38 oracle 1001 asmadmin ? 19 76g 27:03 185m 4960 0 0 semtimedo ..4.2... ora_arc5_dben1 80614 1 oracle 20 0 76.1g 93m 20m S 0.0 0.0 9:43.50 oracle 1001 asmadmin ? 5 76g 9:43 185m 4988 0 0 semtimedo ..4.2... ora_arc2_dben1 27568 1 oracle -2 0 76.1g 88m 17m S 0.6 0.0 3825:00 oracle 1001 asmadmin ? 18 75g 63,45 185m 3732 0 0 poll_sche ..4.2... ora_lms1_dben1 27564 1 oracle -2 0 76.1g 88m 17m S 0.6 0.0 3781:02 oracle 1001 asmadmin ? 0 75g 63,01 185m 3732 0 0 poll_sche ..4.2... ora_lms0_dben1 24037 1 oracle 20 0 76.1g 86m 19m S 0.0 0.0 1252:39 oracle 1001 asmadmin ? 22 75g 20,52 185m 52m 0 0 semtimedo ..4.2... ora_dbw0_dbcn1 25171 1 oracle 20 0 76.0g 85m 27m S 0.0 0.0 2295:56 oracle 1001 asmadmin ? 1 75g 38,15 185m 4644 1 0 semtimedo ..4.2... ora_rsm0_dbcn1 24041 1 oracle 20 0 76.1g 85m 18m S 0.0 0.0 1157:28 oracle 1001 asmadmin ? 22 75g 19,17 185m 52m 0 0 semtimedo ..4.2... ora_dbw2_dbcn1 24039 1 oracle 20 0 76.1g 83m 18m S 0.0 0.0 1173:16 oracle 1001 asmadmin ? 0 75g 19,33 185m 51m 0 0 semtimedo ..4.2... ora_dbw1_dbcn1 28215 1 oracle 20 0 76.1g 83m 19m S 0.0 0.0 70:07.81 oracle 1001 asmadmin ? 23 75g 70:07 185m 4172 0 0 semtimedo ..4.2... ora_arc1_dben1 27557 1 oracle 20 0 76.0g 80m 17m S 2.8 0.0 23005:17 oracle 1001 asmadmin ? 3 75g 383,25 185m 3564 0 0 poll_sche ..4.2... ora_dia0_dben1 --//不知道为什么这个版本的swap显示这么大.实际上应该是0. 3.难道11g下有bug还是一些问题.我在测试重新测试看看.我以前看到不是这样的情况: SYS@book> @ ver1 PORT_STRING VERSION BANNER ------------------------------ -------------- -------------------------------------------------------------------------------- x86_64/Linux 2.4.xx 11.2.0.4.0 Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production SYS@book> create pfile='/tmp/@.ora' from spfile; File created. --//修改/tmp/book.ora文件,修改加入如下: *.use_large_pages=false *.pre_page_sga=true SYS@book> startup pfile='/tmp/book.ora; ORACLE instance started. Total System Global Area 643084288 bytes Fixed Size 2255872 bytes Variable Size 205521920 bytes Database Buffers 427819008 bytes Redo Buffers 7487488 bytes Database mounted. Database opened. --//忘记输入结尾的引号,竟然也能通过. SYS@book> show parameter pre_page_sga NAME TYPE VALUE ------------ ------- ------- pre_page_sga boolean TRUE $ cat /proc/meminfo | grep HugePages AnonHugePages: 0 kB HugePages_Total: 104 HugePages_Free: 104 HugePages_Rsvd: 0 HugePages_Surp: 0 --//可以发现HugePages_Total=HugePages_Free.表明没有使用hugepages. SYS@book> show sga Total System Global Area 643084288 bytes Fixed Size 2255872 bytes Variable Size 205521920 bytes Database Buffers 427819008 bytes Redo Buffers 7487488 bytes # top -u oracle --//按照res排序. top - 09:22:00 up 1065 days, 45 min, 1 user, load average: 0.18, 0.14, 0.10 Tasks: 245 total, 1 running, 244 sleeping, 0 stopped, 0 zombie Cpu(s): 0.0%us, 0.1%sy, 0.0%ni, 99.9%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Mem: 132261196k total, 80358708k used, 51902488k free, 2489960k buffers Swap: 31455264k total, 2292k used, 31452972k free, 72454796k cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 22305 oracle 20 0 884m 645m 618m S 0.0 0.5 0:00.39 ora_arc0_book 22303 oracle 20 0 859m 639m 634m S 0.0 0.5 0:00.82 oraclebook (DESCRIPTION=(LOCAL=YES)(ADDRESS=(PROTOCOL=beq))) 22291 oracle 20 0 859m 638m 632m S 0.0 0.5 0:00.66 ora_mmon_book 22323 oracle 20 0 858m 634m 628m S 0.0 0.5 0:00.40 ora_cjq0_book 22283 oracle 20 0 868m 628m 625m S 0.0 0.5 0:00.20 ora_lgwr_book 22277 oracle 20 0 860m 626m 618m S 0.0 0.5 0:00.17 ora_dbw0_book 22279 oracle 20 0 859m 625m 617m S 0.0 0.5 0:00.28 ora_dbw1_book 22281 oracle 20 0 859m 625m 617m S 0.0 0.5 0:00.26 ora_dbw2_book 22287 oracle 20 0 854m 625m 622m S 0.0 0.5 0:00.30 ora_smon_book 22289 oracle 20 0 855m 625m 622m S 0.0 0.5 0:00.27 ora_reco_book 22271 oracle 20 0 854m 624m 622m S 0.0 0.5 0:00.30 ora_dbrm_book 22307 oracle 20 0 876m 621m 618m S 0.0 0.5 0:00.23 ora_arc1_book 22259 oracle 20 0 855m 621m 619m S 0.0 0.5 0:00.49 ora_pmon_book 22293 oracle 20 0 854m 621m 618m S 0.0 0.5 0:00.37 ora_mmnl_book 22285 oracle 20 0 854m 620m 618m S 0.0 0.5 0:00.35 ora_ckpt_book 22273 oracle 20 0 854m 620m 617m S 0.0 0.5 0:00.31 ora_dia0_book 22275 oracle 20 0 853m 619m 617m S 0.0 0.5 0:00.25 ora_mman_book 22295 oracle 20 0 859m 619m 617m S 0.0 0.5 0:00.22 ora_d000_book 22261 oracle 20 0 853m 619m 617m S 0.0 0.5 0:00.20 ora_psp0_book 22269 oracle 20 0 853m 619m 617m S 0.0 0.5 0:00.24 ora_diag_book 22263 oracle -2 0 853m 619m 617m S 1.8 0.5 0:03.61 ora_vktm_book 22267 oracle 20 0 853m 619m 617m S 0.0 0.5 0:00.24 ora_gen0_book 22297 oracle 20 0 854m 618m 616m S 0.0 0.5 0:00.15 ora_s000_book --//可以发现RES消耗很大的内存. 这样页面表消耗如下: $ cat /proc/meminfo | grep -i page AnonPages: 228148 kB PageTables: 39968 kB AnonHugePages: 0 kB HugePages_Total: 104 HugePages_Free: 104 HugePages_Rsvd: 0 HugePages_Surp: 0 Hugepagesize: 2048 kB --//重新启动看看: SYS@book> show parameter pre_page_sga NAME TYPE VALUE ------------ ------- ------ pre_page_sga boolean FALSE $ cat /proc/meminfo | grep -i page AnonPages: 201812 kB PageTables: 12536 kB AnonHugePages: 0 kB HugePages_Total: 309 HugePages_Free: 98 HugePages_Rsvd: 98 HugePages_Surp: 205 Hugepagesize: 2048 kB --//pre_page_sga=false,使用hugepages. top - 09:31:30 up 1065 days, 54 min, 1 user, load average: 0.12, 0.10, 0.09 Tasks: 243 total, 1 running, 242 sleeping, 0 stopped, 0 zombie Cpu(s): 0.0%us, 0.0%sy, 0.0%ni, 99.9%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Mem: 132261196k total, 80083584k used, 52177612k free, 2489960k buffers Swap: 31455264k total, 2292k used, 31452972k free, 71826716k cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 5459 oracle 20 0 69752 48m 716 S 0.3 0.0 19:08.01 tmux new-session -s oracle -n bashsqlplus -d 22431 oracle 20 0 859m 34m 29m S 0.0 0.0 0:00.60 oraclebook (DESCRIPTION=(LOCAL=YES)(ADDRESS=(PROTOCOL=beq))) 22417 oracle 20 0 859m 33m 28m S 0.0 0.0 0:00.47 ora_mmon_book 22451 oracle 20 0 858m 28m 23m S 0.0 0.0 0:00.19 ora_cjq0_book 22403 oracle 20 0 860m 22m 13m S 0.0 0.0 0:00.03 ora_dbw0_book 22405 oracle 20 0 859m 21m 13m S 0.0 0.0 0:00.02 ora_dbw1_book 22407 oracle 20 0 859m 21m 13m S 0.0 0.0 0:00.02 ora_dbw2_book 22413 oracle 20 0 854m 21m 18m S 0.0 0.0 0:00.06 ora_smon_book 22415 oracle 20 0 855m 20m 18m S 0.0 0.0 0:00.02 ora_reco_book 22397 oracle 20 0 854m 20m 17m S 0.0 0.0 0:00.02 ora_dbrm_book 22385 oracle 20 0 855m 17m 14m S 0.0 0.0 0:00.03 ora_pmon_book 22419 oracle 20 0 854m 16m 13m S 0.0 0.0 0:00.06 ora_mmnl_book 22409 oracle 20 0 868m 16m 14m S 0.0 0.0 0:00.04 ora_lgwr_book 22411 oracle 20 0 854m 16m 14m S 0.0 0.0 0:00.04 ora_ckpt_book 22435 oracle 20 0 876m 16m 13m S 0.0 0.0 0:00.02 ora_arc1_book 22399 oracle 20 0 854m 16m 13m S 0.0 0.0 0:00.08 ora_dia0_book 22433 oracle 20 0 876m 16m 13m S 0.0 0.0 0:00.02 ora_arc0_book --//RES仅仅20-30M上下. 总之: 我个人建议安装oracle,设置使用hugepages作为必要的步骤.设置pre_page_sga=true的情况下,更加必要.