GoldenGate学习2–Oracle GoldenGate technical architecture

5月 15th, 2018

Oracle GoldenGate Technical Architecture
1. Objectives:
1. Describe Oracle GoldenGate uses;
2. Lean the components of Oracle GoldenGate;
3. Explain change capture and delivery(with and without a dump);
4. Explain inital data load;
5. Contrast batch and online operation;
6. Explain Oracle GoldenGate checkpointing;
7. Describe Oracle GoldenGate parameters, process groups and GGSCI commands;
2. Oracle GoldenGate Users:
1. Primarily userd for change data capture and delivery from database transaction logs;
2. Can optionally be used for initial load directly from database tables:
1. Especially usefull for synchronizing heterogeneous databases,对异构数据库之间同步数据特别有用;
2. Database-specific methods may be preferable for homogeneous configurations,同构数据库之间最好使用数据库本身的方法;
3. Oracle GlodenGate Components:
1. Extract:process,source;
2. Data Pump:process,source;
3. Replicat:process,target;
4. Trails or Extract files:file,source and target;
5. Checkpoints:process;
6. Manager:process,source and target;
7. Collector:process,target;
4. 使用中的各种场景:
1. Change Data Capture and Delivery;
2. Change Data Capture and Delivery using a Data Pump;
3. Bidirectional Configuration;
4. Initial Load;
5. Abount the trails:
1. To support the continuous extraction and replication of database changes, Oracle GoldenGate stores the captured changes temporarily on disk in a series of files called a trail;
2. A trail can exist on the source or target system, or an intermediary system, depending on your configuration;
3. On the local system it’s know as an extract trail(or local trail), On a remote system it’s known as a remote trail;
4. All files names in a trail begin with the same two characters which you assign when you create the trail(max 10m default). As files are created, each name is appended with a unique, six-digit serial number from 000000 through 999999, for example:/gg11/dirdat/tr000018;
6. Data Pump:In most business cases, you should use a data pump, some reasons for using a data pump include the followint;
1. Protection against network and target failures;
2. Implementing serveral phases of data filtering or transformation;
3. Consolidating data from many sources to a central target;
4. Synchronizing one source with multiple targets;
7. Procesing Methods:
1. Oracle GoldenGate can be configured for the following purposes:
1. A static extraction of selected data records from one database and loading of those records to another database;
2. Online or batch extraction and replication of selected transactional data changes and DDL changes(for supported database) to keep source and target data consistent;
3. Extraction from database and replication to a file outside the database;
2. Methods:
1. An online process runs until stopped by a user, you can use online processes to continuously extract and replicate transactional changes and DDL changes(where supported);
2. A bach run, or special run, process extracts or replicates database changes that were generated within know begin and end points;
3. A task is a special type of batch run process and is used for certain initial load methods. A task is a configuration in which Extract communicates directly with Replicat over TCP/OP. Neither a Collector process nor temporary disk storage in a trail or file is used;
8. Checkpointing:Capture, Pump, and Delivery save positions to a checkpoint file so they can recover in case of failure;
9. Parameters, Process Groups and Commands:
1. GoldenGate processes are configured by ASCII parameter files;
2. A process group consists of:
1. An Extract or Replicat process;
2. Associated parameter file;
3. Associated checkpoint file;
4. Any other files associated with that process;
5. Each process group on a system must have a unique group name;
3. Processes are added and started using the GoldenGate Software Command Interface(GGSCI) with the group name;
4. GGSCI commands also add trails, check process status,etc;