预约MongoDB university的DBA认证考试

诗檀软件 MongoDb学习群 421431253

 

 

现在MongoDB university提供DBA认证考试课程:

SCHEDULE

EXAM START END REGISTER
C100DEV: MongoDB Certified Developer Associate Exam Apr 21, 2015 Apr 28, 2015 REGISTER
C100DBA: MongoDB Certified DBA Associate Exam Apr 21, 2015 Apr 28, 2015 REGISTER
C100DBA: MongoDB Certified DBA Associate Exam Jul 21, 2015 Jul 28, 2015 Opens Apr 28, 2015
C100DEV: MongoDB Certified Developer Associate Exam Jul 21, 2015 Jul 28, 2015 Opens Apr 28, 2015
C100DBA: MongoDB Certified DBA Associate Exam Oct 20, 2015 Oct 27, 2015 Opens Jul 28, 2015
C100DEV: MongoDB Certified Developer Associate Exam Oct 20, 2015 Oct 27, 2015 Opens Jul 28, 2015
C100DBA: MongoDB Certified DBA Associate Exam Jan 19, 2016 Jan 26, 2016 Opens Oct 27, 2015
C100DEV: MongoDB Certified Developer Associate Exam Jan 19, 2016 Jan 26, 2016 Opens Oct 27, 2015

 

用户可以点击上面的REgister来预约网上考试。 考试分成 Developer Associate (C100DEV) 和 DBA Associate(C100DBA) 2种, Maclean选择的是 DBA Associate DBA专员, 考试费用为150美元。

 

预约mongodb dba认证考试 c100DEV

 

完成上述注册后,可以通过信用卡支付。 之后会被重定向到prod.examity.com/Mongodb 考试预约网站预约具体的考试时间, 需要先完成用户profile信息填写后具体schedule 时间。

 

C100DBA 的考纲如下:

 

Exam Details

  • This exam is based on MongoDB 2.6.
  • There are no prerequisites. Anyone may take the exam but we do recommend you take an in-person training or M102 and M202. Test takers should also make use of other recommended preparation materials.
  • MongoDB certification exams are delivered online using a web proctoring solution.
  • Complete the Computer Readiness Check to ensure your system meets the necessary hardware and software requirements to complete an exam.
  • To take the exam, you must schedule an exam session with our proctoring partner, Examity. Once you have registered for the exam, you will receive scheduling instructions.
  • You may complete the exam at any time, day or night between the start and end dates.
  • Test takers have 90 minutes to complete an exam.
  • There is no penalty for incorrect answers.
  • Exam scores are based on the number of correct answers with an adjustment made for the overall difficulty of the exam as determined by the data and expert assessment.
  • Exam question types are multiple choice and check all that apply.
  • Exam results will be available within 3 weeks following the close of the exam period. We need time to review any questions raised by the proctors and calculate exam results.
  • Please note that we are no longer including a free retake with the exam fee.

Required MongoDB Knowledge

  • Philosophy & Features: performance, JSON, BSON, fault tolerance, disaster recovery, horizontal scaling, and the Mongo shell
  • CRUD: Create, Read, Update, and Delete operations
  • Indexing: single key, compound, multi-key, mechanics, and performance
  • Aggregation: pipeline, operators, memory usage, sort, skip, and limit
  • Replication: configuration, oplog concepts, write concern, elections, failover, and deployment to multiple data centers
  • Sharding: components, when to shard, balancing, shard keys, and hashed shard keys
  • Application Administration: data files, journaling, authentication, and authorization
  • Server Administration: performance analysis, diagnostics and debugging, maintenance, backup, and recovery

 

 

C100DEV的考纲如下:

 

ABOUT THE EXAM

The MongoDB Certified Developer, Associate Level exam is intended for individuals with knowledge of the fundamentals of designing and building applications using MongoDB. We recommend this certification for software engineers who have a solid understanding of MongoDB fundamentals and some professional experience developing applications with MongoDB. The knowledge and skills required for certification are detailed below.

Exam Details

  • This exam is based on MongoDB 2.6.
  • There are no prerequisites. Anyone may take the exam but we do recommend you complete an in-person training or one of the following online courses: M101J, M101JS, M101N, or M101P. Test takers should also make use of other recommended preparation materials.
  • MongoDB certification exams are delivered online using a web proctoring solution.
  • Complete the Computer Readiness Check to ensure your system meets the necessary hardware and software requirements to complete an exam.
  • To take the exam, you must schedule an exam session with our proctoring partner, Examity. Once you have registered for the exam, you will receive scheduling instructions.
  • You may complete the exam at any time, day or night between the start and end dates.
  • Test takers have 90 minutes to complete an exam.
  • There is no penalty for incorrect answers.
  • Exam scores are based on the number of correct answers with an adjustment made for the overall difficulty of the exam as determined by the data and expert assessment.
  • Exam question types are multiple choice and check all that apply.
  • Exam results will be available within 3 weeks following the close of the exam period. We need time to review any questions raised by the proctors and calculate exam results.
  • Please note that we are no longer including a free retake with the exam fee.

Required MongoDB Knowledge

  • Philosophy & Features: performance, JSON, BSON, fault tolerance, disaster recovery, horizontal scaling, and the Mongo shell
  • CRUD: Create, Read, Update, and Delete operations
  • Data Modeling: embedding, references, document growth, modeling one-to-one and one-to-many relationships, modeling for atomic operations, modeling tree structures
  • Indexing: single key, compound, multi-key, mechanics, and performance
  • Aggregation: pipeline, operators, memory usage, sort, skip, and limit
  • Replication: configuration, oplog concepts, write concern, elections, failover, and deployment to multiple data centers
  • Sharding: components, when to shard, balancing, shard keys, and hashed shard keys

 

 

Oracle11g升级项目实施流程

下载SHOUG成员Oracle ACS首席工程师周国宏分享:《Oracle11g升级项目实施流程》

《Oracle11g新特性介绍》

下载SHOUG成员Oracle ACS首席工程师周国宏分享:《Oracle11g新特性介绍》

 

Oracle Exadata Database Machine Reracking Checklist

Oracle ASM和VxCFS的比较

关于VxCFS和ASM
 
 
ASM的主要优点在于 成本的优势:
1.ASM是免费的存储解决方案; 
2.磁盘管理与自动IO负载均衡,可以免除手动进行IO调优;
3.ASM功能绑定在Oracle内核中,无需依靠安装HACMP或第三方HA软件;(注10g中可能仍需要ha来存放OCR和Votedisk)
4.自动重组数据,较稳定的保持负载均衡
5.动态添加移除磁盘,对oracle数据库几乎透明;
6.性能上ASM接近于使用裸设备
 
虽然ORACLE 10g的早期版本,ASM很不稳定,而且在PSU 10.2.0.4.4发布时,其中修复的ASM bug数仍达到了8个,但在PSU 10.2.0.4.5及其之后,没有发现有修复ASM bug的情况,所以可以相信在PSU 10.2.0.4.4之后,ASM功能已趋于稳定(注: 在PSU 10.2.0.5.6发布时修复了1个ASM bug;在PSU 11.2.0.3.1发布时修复了6个bug)
 
缺点是:ASM的内部结构较为黑盒,当出现例如ASM header丢失时,需要ASM相关专业人员负责修复。
 
 
Veritas Cluster File System VxCFS的优势是管理方便,较ASM在技术上更透明,一旦发生故障可以更快地定位问题。
 
目前国内 VxCFS在电信业有一些核心库使用的例子, 而 ASM在银行、政府机构等行业已经有了广泛的使用,部分银行用户已部署多达上百套RAC+ASM库。

11g deferred_segment_creation特性

11g中的 deferred_segment_creation 延迟段创建特性,在CREATE TABLE DDL执行时实际不会在指定的表空间上生成segment ,而会延迟到实际有第一次INSERT或其他方式加载数据后才会产生segment。
 
该deferred_segment_creation特性的优点是:
 
1. 当需要创建大量表时可以节约时间
2. 当系统中存在大量空表/空分区时可以节约空间
 
 
该deferred_segment_creation特性的缺点是:
 
1. 由于要在第一次INSERT或其他加载数据方式时才产生segment段,而段的创建需要在表空间上分配空间allocate space,若短期内
大量空表存在插入的需求,则可能在短期内出现空间分配争用
 
2. deferred_segment_creation引入了少量的BUG.
 
以下是11.2.0.3上存在的一些bug,部分在psu或者bp中修复了:
 
NB Bug Fixed Description
15866428 11.2.0.4, 12.1.0.0 ORA-14766 / ORA-14403 during concurrent partition maintenance
14252187 12.1.0.0 ORA-600 [qesmaGetTblSeg1] from deferred segment creation in RAC
13986244 11.2.0.3.BP14, 11.2.0.4, 12.1.0.0 Various ORA-600 seen with deferred segment creation in RAC
13611310 12.1.0.0 Parallel DML with LOBs fails with ORA-7445 [qesmaGetFromLocalOrQCCache]
12614714 11.2.0.4, 12.1.0.0 ORA-1950 occurs when executing DML after EXCHANGE PARTITION and DROP USER
13649031 11.2.0.3.4, 11.2.0.3.BP06, 11.2.0.4, 12.1.0.0 ORA-10637 occurs on SHRINK of a partitioned table with deferred segments
13497523 11.2.0.3.BP15, 11.2.0.4, 12.1.0.0 Errors from SQLLDR loads into non-partitioned tables with deferred segment creation
* 13326736 11.2.0.2.8, 11.2.0.2.BP18, 11.2.0.3.3, 11.2.0.3.BP05, 11.2.0.4, 12.1.0.0 Dictionary corruption / ORA-959 due to DROP TABLESPACE
12535346 11.2.0.3.3, 11.2.0.3.BP07, 12.1.0.0 ORA-7445 [kxccexi] using referential integrity constraints with deferred segments or interval partitions
12358753 12.1.0.0 INDEX_STATS has wrong values for ANALYZE of deferred segmentindexes
11930350 12.1.0.0 Deadlock / undetected FK violation from DML on REFERENCE partitioned table
 
 
建议:
 
1. 对于存在较多空表或空分区且存在空间压力的,对性能、响应时间没有太高要求的系统可以考虑使用该特性
2. 对对性能、响应时间有较高要求的库建议关闭该特性,deferred_segment_creation=false

Oracle RAC ora.crf ologgerd

loggerd 进程属于ora.crf服务,该服务负责收集一些OS的CPU和Memory信息,作为对实例本身监控的补充,由于很多环境中没有部署OSW脚本监控OS导致很多RAC问题由于缺少OS信息而无法进一步诊断, 所以需要ora.crf收集, 但ora.crf不能替代 OSW。
建议在重要环境中部署OSW监控。 在有orca等监控工具的前提下可以考虑禁用CHM。
对于上述问题可以考虑KILL ologgerd进程释放资源。
As a temporary work around, you can kill ologgerd and delete the contents in the BDB directory. osysmond should respawn ologgerd and new bdb file will get created. The past data is lost when this is done.
 
具体可以参考:Cluster Health Monitor (CHM) FAQ [ID 1328466.1]
crsctl stop has的话 会停止ora.crf服务,应当会停掉该进程
crsctl stop cluster的话可能不会停止
可以用 $GRID_HOME/bin/crsctl stop res ora.crf -init 命令手动仅停止 ora.crf 服务
手动Kill ologgerd进程的话osysmond 会自动重启该进程respawn ologgerd ,但也可以起到释放资源的目的。

Oracle bbed的代码风格

Oracle bbed的代码风格

    371 /* K_BTTRDA, KDDBTDATA: KTB Data, data block layers defn */
    372 static const kutbl *const kutbltt[] =
    373 {
    374   &kutblcb,                                                   /* cache layer */
    375   &kutbltb,                                             /* transaction layer */
    376   &kutbldb,                                                    /* data layer */
    377   &kutbltck                                                       /* TAILCHK */
    378 };
    379 
    380 /* K_BTTRDA, KDDBTINDEX: KTB Data, index LEAF block layers defn */
    381 static const kutbl *const kutbltxl[] =
    382 {
    383   &kutblcb,                                                   /* cache layer */
    384   &kutbltb,                                             /* transaction layer */
    385   &kutbldxl,                                                   /* data layer */
    386   &kutbltck                                                       /* TAILCHK */
    387 };
    388 
    389 /* K_BTTRDA, KDDBTINDEX: KTB Data, index BRANCH block layers defn */
    390 static const kutbl *const kutbltxb[] =
    391 {
    392   &kutblcb,                                                   /* cache layer */
    393   &kutbltb,                                             /* transaction layer */
    394   &kutbldxb,                                                   /* data layer */
    395   &kutbltck                                                       /* TAILCHK */
    396 };
    397 
    398 /* K_BTTRDA, KDDBTLOBF: KTB Data, lob block layers defn */
    399 static const kutbl *const kutbltl[] =
    400 {
    401   &kutblcb,                                                   /* cache layer */
    402   &kutbltb,                                             /* transaction layer */
    403   /*&kutbldl,*/                                                     /* lob layer */
    404   &kutbltck                                                       /* TAILCHK */



bbed的源码是这样做的
KTB Data, data block layers
判断一个块的类型 然后决定 其由那几个部分组成

这样比较先进一点

例如 首先判断 block_type 之后 有相关的函数来初始化

initial_kcbh();
initial_ktbbh();
如果没有该部分就不初始化。