TimesTen 18c 配置 HugePage

按照文檔TimesTen 18.1.2.1 Classic模式安裝與配置過程，在Linux 7上安裝TimesTen 18.1.3.2.0，一切順利，創建示例數據庫重成功。

但是將數據庫內存增大到256G時，報錯:

$ ttisql sampledb

Copyright (c) 1996, 2020, Oracle and/or its affiliates. All rights reserved.
Type ? or "help" for help, type "exit" to quit ttIsql.

connect "DSN=sampledb";
  836: Cannot create database shared-memory segment, error 0
  703: Subdaemon connect to database failed with error TT836
The command failed.
Done.

原因是當數據庫內存超過256G時，需要開啓HugePage。參見Database Connection Fails With Cannot create data store shared-memory segment, error 22 (Doc ID 1504153.1)。

以下操作參考文檔Oracle® TimesTen In-Memory Database Installation, Migration, and Upgrade Guide Release 18.1 - Configure HugePages

首先查看Hugepage的單位，一般都是2M：

$ cat /proc/meminfo | grep Hugepagesize
Hugepagesize:       2048 kB

因爲需求是256G，所有需要的HugePage數量爲：

256 * 1024M = 262144 MB/ 2 MB = 131072

考慮到還有一些其它開銷，將131072調整爲132000。

查看instance admin的用戶名和group信息:

$ id
uid=55000(oracle) gid=10000(timesten) groups=10000(timesten),10(wheel) context=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023

記錄instance admin爲oracle，group id爲10000.

編輯文件/etc/sysctl.conf，添加以下兩行：

vm.nr_hugepages=132000
vm.hugetlb_shm_group=10000

其中10000爲instance admin的group id。132000是我們之前計算的值。

使其生效：

$ sudo sysctl -p
vm.nr_hugepages = 131072
vm.hugetlb_shm_group = 10000

編輯文件/etc/security/limits.conf，添加以下兩行：

oracle soft memlock 300000000
oracle hard memlock 300000000

其中oracle爲instace admin用戶名，300000000是選取了一個大於以下計算結果的值：

256*1024*1024 = 268435456

然後用戶需退出再登錄，使其生效。

然後建庫就沒有問題了：

$ ttisql sampledb

Copyright (c) 1996, 2020, Oracle and/or its affiliates. All rights reserved.
Type ? or "help" for help, type "exit" to quit ttIsql.



connect "DSN=sampledb";
Connection successful: DSN=sampledb;UID=oracle;DataStore=/u01/database/data/ttdb;DatabaseCharacterSet=AL32UTF8;ConnectionCharacterSet=US7ASCII;LogFileSize=256;DRIVER=/home/oracle/tt181/install/lib/libtten.so;LogBufMB=256;LogDir=/u01/database/log;PermSize=262144;TempSize=1024;OracleNetServiceName=ttorcl;
(Default setting AutoCommit=1)
Command> dssize
The following values are in MB:

  PERM_ALLOCATED_SIZE:      262144
  PERM_IN_USE_SIZE:         13.979
  PERM_IN_USE_HIGH_WATER:   13.979
  TEMP_ALLOCATED_SIZE:      1024
  TEMP_IN_USE_SIZE:         15.552
  TEMP_IN_USE_HIGH_WATER:   15.759

Command> dssize g
The following values are in GB:

  PERM_ALLOCATED_SIZE:      256
  PERM_IN_USE_SIZE:         .014
  PERM_IN_USE_HIGH_WATER:   .014
  TEMP_ALLOCATED_SIZE:      1
  TEMP_IN_USE_SIZE:         .015
  TEMP_IN_USE_HIGH_WATER:   .015

其它監控數據：

$ cat /proc/meminfo|grep -i huge
AnonHugePages:    143360 kB
ShmemHugePages:        0 kB
HugePages_Total:   132000
HugePages_Free:    131868
HugePages_Rsvd:    131690
HugePages_Surp:        0
Hugepagesize:       2048 kB
[oracle@tthugepage ~]$ ipcs -a

------ Message Queues --------
key        msqid      owner      perms      used-bytes   messages

------ Shared Memory Segments --------
key        shmid      owner      perms      bytes      nattch     status
0xf803da71 360448     oracle     660        1048576    1
0x1903cda4 458753     oracle     660        276316553216 10
0x1a03cda4 491522     oracle     660        134217728  2

------ Semaphore Arrays --------
key        semid      owner      perms      nsems
0xf803da71 196608     oracle     660        1
0x1903cda4 262145     oracle     660        2155