17.2.3 Copying Deferred Transactions to New Destinations
17.2.4 Maintenance Procedures
17.2.5 Propagating Deferred RPCs
17.2.6 Scheduling Propagation (Oracle8 only)
17.3 DBMS_DEFER: Building Deferred Calls
17.3.1 Getting Started with DBMS_DEFER
17.3.2 Basic RPCs
17.3.3 Parameterized RPCs
17.4 DBMS_DEFER_QUERY: Performing Diagnostics and Maintenance
17.4.1 Getting Started with DBMS_DEFER_QUERY
Table of Contents
Part I: Overview
Part II: Application Development Packages
Part III: Server Management Packages
Part IV: Distributed Database Packages
Structure of This Book
Nội dung
14.4.2.1.1 Exceptions The CREATE_SNAPSHOT_REPGROUP procedure raises the following exceptions: Name Number Description commfailure −23317 Unable to communicate with master dbnotcompatible −23375 Attempt to use SYNCHRONOUS propagation in pre−7.3 database duplicaterepgroup −23374 Replication group gname already exists nonmaster −23312 The master parameter is not a master site norepoption −23364 Replication option not installed typefailure −23319 propagation_mode not specified correctly 14.4.2.1.2 Restrictions Note the following restrictions on calling CREATE_SNAPSHOT_REPGROUP: • You must be connected to the replication administrator account (typically REPADMIN) to call the CREATE_SNAPSHOT_REPGROUP procedure. • The snapshot group name must match the name of the master replication group. 14.4.2.2 The offline snapshot instantiation procedure The procedure for performing offline instantiation of snapshots in an advanced replication environment (using the CREATE SNAPSHOT command and the DBMS_OFFLINE_SNAPSHOT and DBMS_REPCAT packages) follows: 1. Create a snapshot log for each master table if one does not already exist. 2. Create a snapshot of each master table in the master database, and in the same schema as the master table. Of course, the name of the snapshot will have to be different from the name of the master table. The CREATE SNAPSHOT statement must also include a loopback database link qualifier. CREATE SNAPSHOT snp_countries AS SELECT * FROM countries@D7CA.BIGWHEEL.COM@TCPIP 3. Perform user exports of all schema that own master tables. You should be logged on to the schema owner account for these exports. The only tables that you need to export are the snapshot base tables −− that is, those whose names begin with "SNAP$_". 4. Copy the export dump file(s) to the new snapshot site(s). 5. Use CREATE_SNAPSHOT_REPGROUP at the snapshot sites to create a new snapshot replication object group. The name of this object group should be the same as the name of the replication group of which the master tables are members. [Appendix A] What's on the Companion Disk? 14.4.2 Creating and Dropping Snapshot Replication Groups 631 BEGIN DBMS_REPCAT.CREATE_SNAPSHOT_REPGROUP( gname => 'SPROCKET', master => 'D7CA.BIGWHEEL.COM', comment => 'Group created on '||sysdate|| ' by '||user, propagation_mode=> 'ASYNCHRONOUS'); END; 6. Call DBMS_OFFLINE_SNAPSHOT.BEGIN_LOAD to begin loading the data from the export file(s). You must call the procedure for every snapshot you plan to import. BEGIN DBMS_OFFLINE_SNAPSHOT.BEGIN_LOAD( gname => 'SPROCKET', sname => 'SPROCKET', master_site => 'D7CA.BIGWHEEL.COM' snapshot_oname => 'SNP_COUNTRIES' storage_c => 'TABLESPACE sprocket_data STORAGE (INITIAL 64K)' comment => 'Load of COUNTRIES snapshot begun at '||sysdate); END; 7. Import the snapshot base table(s) from the export file(s) created in step 4. 8. Call DBMS_OFFLINE_SNAPSHOT.END_LOAD for each snapshot when the load is complete. BEGIN DBMS_OFFLINE_SNAPSHOT.END_LOAD( gname => 'SPROCKET' sname => 'SPROCKET' snapshot_oname => 'SNP_COUNTRIES'); END; 14.4.2.3 The DBMS_REPCAT.DROP_SNAPSHOT_REPGROUP procedure The DBMS_REPCAT package's DROP_SNAPSHOT_REPGROUP procedure is the counterpart to the CREATE_SNAPSHOT_REPGROUP procedure. As you would suspect, this procedure drops an existing snapshot replication group, and optionally, all member snapshots. Here's the specification: PROCEDURE DBMS_REPCAT>DROP_SNAPSHOT_REPGROUP (gname IN VARCHAR2, drop_contents IN BOOLEAN := FALSE); Parameters are summarized in the following table. Name Description gname Name of the snapshot group. drop_contents If TRUE, objects in gname are dropped. If FALSE (the default) they are simply no longer replicated. 14.4.2.3.1 Exceptions The DROP_SNAPSHOT_REPGROUP procedure raises the following exceptions: Name Number Description missingrepgroup −23373 Replication group gname does not exist [Appendix A] What's on the Companion Disk? 14.4.2 Creating and Dropping Snapshot Replication Groups 632 nonmaster −23313 Calling site is not a snapshot site 14.4.2.3.2 Restrictions If drop_contents is set to FALSE, the triggers created to support snapshot modifications remain. 14.4.2.3.3 Example The following example illustrates the dropping of a snapshot replication group with the DROP_SNAPSHOT_REPGROUP procedure: BEGIN DBMS_REPCAT.DROP_SNAPSHOT_REPGROUP( gname => 'SPROCKET', drop_objects => TRUE); END; Here, we drop the snapshot replication group SPROCKET and drop the member snapshots as well. 14.4.3 Adding and Removing Snapshot Replication Group Objects The CREATE_SNAPSHOT_REPOBJECT and DROP_SNAPSHOT_REPOBJECT procedures add and remove objects, respectively, from a snapshot replication group. These objects may be snapshots, packages, package bodies, procedures, synonyms, or views. 14.4.3.1 The DBMS_REPCAT.CREATE_SNAPSHOT_REPOBJECT procedure The CREATE_SNAPSHOT_REPOBJECT procedure adds an object to a snapshot replication group. For new snapshot objects, this procedure generates row−level replication triggers for snapshots if the master table uses row−level replication. The specifications differ for Oracle7 and Oracle8 as follows. Here is the Oracle7 specification: PROCEDURE DBMS_REPCAT. CREATE_SNAPSHOT_REPOBJECT (sname IN VARCHAR2, oname IN VARCHAR2, type IN VARCHAR2, ddl_text IN VARCHAR2 := '', comment IN VARCHAR2 := '', gname IN VARCHAR2 := '', gen_objs_owner IN VARCHAR2 := ''); Here is the Oracle8 specification: PROCEDURE DBMS_REPCAT.CREATE_SNAPSHOT_REPOBJECT (sname IN VARCHAR2, oname IN VARCHAR2, type IN VARCHAR2, ddl_text IN VARCHAR2 := '', comment IN VARCHAR2 := '', gname IN VARCHAR2 := '', gen_objs_owner IN VARCHAR2 := '', min_communication IN BOOLEAN := TRUE); NOTE: The only difference between the Orace7 and Oracle8 implementations is the addition of the min_communication parameter in Oracle8. Parameters are summarized in the following table. [Appendix A] What's on the Companion Disk? 14.4.2 Creating and Dropping Snapshot Replication Groups 633 Name Description sname Name of schema to which oname belongs. oname Name of object to be added. type Object type. Supported types are PACKAGE, PACKAGE BODY, PROCEDURE, SNAPSHOT, SYNONYM, and VIEW. ddl_text DDL used to create object (for type SNAPSHOT only). comment Comment on object, visible in DBA_REPOBJECT data dictionary view. gname Name of snapshot group to which object is being added. Defaults to sname if not specified. gen_objs_owner Name of the schema in which to create the generated trigger and trigger package or procedure wrapper for the object. Defaults to sname. drop_objects If set to TRUE, object is dropped too. If FALSE (the default), object is only removed from the snapshot group. min_communication (Oracle8 only) Must be FALSE if any master site is running Oracle7. TRUE, the default setting, uses the minimum communication algorithm. 14.4.3.1.1 Exceptions. CREATE_SNAPSHOT_REPGROUP raises the following exceptions: Name Number Description commfailure −23317 Unable to communicate with master site ddlfailure −23318 Unable to perform DDL duplicateobject −23309 Object oname already exists missingobject −23308 Object oname does not exist in master's replication group gname missingremoteobject −23381 Master site has not generated replication support for oname missingschema −23306 Schema sname does not exist misssnapobject −23355 Object oname does not exist at master nonmaster −23312 Master site associated with snapshot group is no longer a master site nonsnapshot −23314 Calling site is not a snapshot site typefailure −23319 Invalid value for type NOTE: CREATE_SNAPSHOT_REPOBJECT is called from the replication administrator (typically REPADMIN) account. If you are creating an snapshot with ddl_text, be sure to specify the schema in which it should be created (if other than the replication administrator account). 14.4.3.1.2 Example The following example illustrates how to add an object to an existing snapshot replication group: BEGIN DBMS_REPCAT.CREATE_SNAPSHOT_REPOBJECT( sname => 'SPROCKET', oname => 'PRICE_LIST', type => 'SNAPSHOT' , ddl_text=> 'CREATE SNAPSHOT SPROCKET.PRICES AS SELECT * FROM [Appendix A] What's on the Companion Disk? 14.4.3 Adding and Removing Snapshot Replication Group Objects 634 PRICES@D7CA.BIGWHEEL.COM' , gnam => 'SPROCKET', gen_objs_owner => 'SPROCKET') END; BEGIN 14.4.3.2 The DBMS_REPCAT.DROP_SNAPSHOT_REPOBJECT procedure The DROP_SNAPSHOT_REPOBJECT procedure drops an object from a snapshot replication group. PROCEDURE DBMS_REPCAT.DROP_SNAPSHOT_REPOBJECT (sname IN VARCHAR2, oname IN VARCHAR2, type IN VARCHAR2, drop_objects IN BOOLEAN := FALSE);. For parameter descriptions, see the table in the Section 14.4.3.1, "The DBMS_REPCAT.CREATE_SNAPSHOT_REPOBJECT procedure"" section. 14.4.3.2.1 Exceptions DROP_SNAPSHOT_REPOBJECT raises the following exceptions: Name Number Description missingobject −23308 Object oname does not exist in master's replication group gname nonsnapshot −23314 Calling site is not a snapshot site typefailure −23319 Invalid value for type 14.4.3.2.2 Restrictions If the type parameter in DROP_REPOBJECT is SNAPSHOT and you do not set the drop_objects parameter to TRUE, replication triggers and associated packages remain in the schema, and deferred transactions (if any) remain in the DEFTRANS queue. 14.4.3.2.3 Example The following example drops an object from a snapshot replication group: DBMS_REPCAT.FTOP_SNAPSHOT_REPOBJECT( sname => 'SPROCKET', oname => 'PRICE_LIST', type => 'SNAPSHOT', drop_objects=> TRUE); END; 14.4.4 Altering a Snapshot Replication Group's Propagation Mode The ALTER_SNAPSHOT_PROPAGATION procedure changes a snapshot replication group's propagation mode. The propagation mode can be either SYNCHRONOUS or ASYNCHRONOUS. When you call this procedure, Oracle does the following: • Pushes any transactions that exist in the deferred RPC queue for the group • [Appendix A] What's on the Companion Disk? 14.4.3 Adding and Removing Snapshot Replication Group Objects 635 . the master table uses row−level replication. The specifications differ for Oracle7 and Oracle8 as follows. Here is the Oracle7 specification: PROCEDURE DBMS_REPCAT. CREATE_SNAPSHOT_REPOBJECT (sname. TRUE); NOTE: The only difference between the Orace7 and Oracle8 implementations is the addition of the min_communication parameter in Oracle8 . Parameters are summarized in the following table. [Appendix. object is only removed from the snapshot group. min_communication (Oracle8 only) Must be FALSE if any master site is running Oracle7 . TRUE, the default setting, uses the minimum communication