1 EM402 MobiLink Tips and Techniques David Fishburn Principal Consultant iAnywhere Solutions

2 Objective To outline a process that makes you productive as quickly as possible Learn techniques to take advantage of this technology Introduce some new Vail (8.0) features and how they can help you Primarily focus on the Vail release

3 Topics Synchronization The Task Database Migration Generating MobiLink Scripts Script Customization Remote Monitoring

4 Synchronization? New technology (since April 1999) Sharing data between consolidated and remote (Synchronization vs Replication) Summary of changes compared to all changes Provides subsets of data defined by client or server Existing Sybase technologies Replication Server SQL Remote (for ASE and ASA)

5 Replication Server Architecture Rep Server ASE ASE LTM ASE DBSRV6 DBLTM ASA MAPIVIM FILE FTP SMTP ASA Other ORACLE DB2

6 SQL Remote ASE MAPIVIM FILE FTP SMTP ASA MAPIVIM FILE FTP SMTP ASA OR

7 SQL Remote with Replication Server Rep Server ASE ASE LTMSSQueue MAPIVIM FILE FTP SMTP ASA

8 MobiLink ASA, ASE, Microsoft, Oracle, IBM ASA, PalmOS, PocketPC, UltraLite HTTP, TCPIPHotSync, Wireless Serial

9 MobiLink and SQL Remote ASA, ASE ASA, Palm, CE, Pagers, Phones SQL RemoteMobiLink

10 Synchronization Process 1. Data is uploaded to the consolidated database 2. Data is downloaded to the remote database

11 Two Main Phases Upload Only records that have changed are uploaded and applied to the consolidated A table at a time Inserts/Updates/Deletes In an order than maintains referential integrity Download A table at a time

12 Synchronization Transactions Upload stream Changes from the remote are applied to the consolidated, followed by a commit Summary of changes Download stream Data is pulled out of the consolidated via a SELECT statement YOU write Transaction is committed (new to Vail) Changes are sent to the remote

13 MobiLink Scripts Scripts control What MobiLink does with the data uploaded from the remote Determines which data is sent to the remotes Script SQL Standard SQL statements INSERT, UPDATE, DELETE and SELECT statements

14 Topics Synchronization The Task Database Migration Generating MobiLink Scripts Script Customization Remote Monitoring

15 The Task Tips are best learned when we have a task to accomplish Start with a Microsoft SQL Server database (the consolidated) Create an identical Adaptive Server Anywhere database (the remote) Write synchronization scripts Get it synchronizing in 10 minutes

16 The Task Consolidated and remote have an identical schema In my experience this is true most of the time If the consolidate and remote have different schemas This is still expected Customization of the MobiLink scripts will be required MobiLink was designed for these cases as well

17 Topics Synchronization The Task Database Migration Generating MobiLink Scripts Script Customization Remote Monitoring

18 Consolidated Database Lets assume your consolidated database is Microsoft SQL Server It could just as easily be Oracle Remote database must be Adaptive Server Anywhere (ASA) UltraLite Compatible ASA schema must be created Required for ASA remotes (for deployment) Required to create an UltraLite database

19 Remote Database Schema We need to migrate the schema from the Microsoft database to an ASA database Use the following ASA features Remote Data Access Database Migration

20 Remote Data Access Sybase feature that allows Access data in relational databases such as Sybase (ASA and ASE), Oracle, and DB2. Access desktop data such as Excel spreadsheets, MS- Access databases, FoxPro, and text files. Access any other data source that supports an ODBC interface. Perform joins between local and remote data. Just to name a few uses…

21 Setup Remote Data Access Use Sybase Central to setup

22 Setup Remote Data Access Setup via SQL statements 1.Create an ASA remote database DBINIT remote.db 2.Define a remote server Mss_fft – ODBC DSN for SQL Server CREATE SERVER mss_cons CLASS 'mssodbc' USING 'mss_fft'; 3.Create an external login for the Microsoft database Assume a user “fishburn” already exists in the MSS database CREATE EXTERNLOGIN "DBA" TO "mss_cons" REMOTE LOGIN "fishburn" IDENTIFIED BY "test";

23 Database Migration (Short way) Special one step ASA stored procedure will migrate Schema Data (optional) Procedure dbo.sa_migrate( IN local_table_ownerVARCHAR(128), IN server_nameVARCHAR(128), IN table_nameVARCHAR(128) DEFAULT NULL, IN owner_nameVARCHAR(128) DEFAULT NULL, IN database_nameVARCHAR(128) DEFAULT NULL, IN migrate_dataBIT DEFAULT 1, IN drop_proxy_tablesBIT DEFAULT 1)

24 Procedure sa_migrate() CALL sa_migrate( 'DBA', 'mss_cons', 'UL%', 'dbo', 'CustDB', 0, 1 ); DBACreate the tables under the DBA owner (ASA) mss_consASA Remote Server UL%Only create the tables that begin with ‘UL’ dboMSS owner of the tables CustDBWhich MSS database (there can be many) 0Do not migrate data 1Drop the proxy tables when finished

25 Verify Results Check only UL% tables were created Ensure no data was migrated

26 Database Migration (Long way) Sometimes you need more flexibility when migrating the schema No convenient ‘UL%’ for the tables you need Errors during the migration process 6 stored procedures can be used instead 1.sa_migrate_create_remote_table_list 2.sa_migrate_create_tables 3.sa_migrate_data 4.sa_migrate_create_remote_fks_list 5.sa_migrate_create_fks 6.sa_migrate_drop_proxy_tables

27 sa_migrate_create_remote_table_ list Will build the list of all tables that need to be migrated CALL sa_migrate_create_remote_table_list( 'mss_cons', null, 'dbo', 'CustDB' ); Populates the table, migrate_remote_table_list, with ALL tables Rows can be removed from this table before proceeding to the next step, sa_migrate_create_tables. These routines are re-runable, pick up where they last left off

28 Topics Synchronization The Task Database Migration Generating MobiLink Scripts Script Customization Remote Monitoring

29 Script Versions MobiLink scripts are organized by script version Use any naming convention you like Have as many versions as you like Project_v100 Project_v101 Project_v102_dev When a remote synchronizes, it must specify which version of the scripts it requires

30 Scripts Scripts are written using Standard SQL INSERT, UPDATE, DELETE, SELECT statements Java (New to Vail) EM404 New MobiLink Technology Scripts are tied to events in the MobiLink Server Each script is optional

31 Script Events For each table that is synchronized bi- directionally the following MobiLink events are required Upload_insert Upload_delete Upload_update Download_cursor If the upload scripts do not exist, no changes from the remote will be applied to the consolidated

32 Example Scripts Scripts (standard SQL) Download_cursor SELECT prop_id, prop_text, last_modified FROM proposal Upload_insert INSERT INTO proposal( prop_id, prop_text, last_modified ) VALUES( ?, ?, ? ) Upload_delete DELETE FROM proposal WHERE prop_id = ? Upload_update UPDATE proposal SET prop_text = ?, last_modified = ? WHERE prop_id = ?

33 Generating MobiLink Scripts Writing these scripts initially can be time consuming and error prone The order of the columns must be the same as the order in the remote database What happens if you need to write scripts for 200 tables?

34 MobiLink Special Mode MobiLink can be started with a special switch that will automatically generate basic scripts for each of the tables No scripts must exist prior to generation If scripts do exist, MobiLink will do nothing MobiLink switches -za+Allow generation of active scripts -zu+Allow automatic addition of users DBMLSrv8 –za+ -zu+ -c DSN=mss_fft –ot cons.txt

35 Verbosity MobiLink has varying levels of verbosity that can be enabled Enabled via the –v command line switch DBMLSRV8 –vcrsn Normally use this when creating scripts c – show the content of each script as it is executed r – show the column values for each of the rows uploaded and downloaded s – show the name of the event that is fired n – show the row count summaries

36 DBMLSync MobiLink client Initiates synchronization with MobiLink DBMLSync must know A unique name for the remote database synchronizing Required for recoverability Which tables must be synchronized Where the MobiLink server is (ie ADDRESS) What protocol to use (ie TCPIP/HTTP)

37 Publication A publication “publishes” which data is available for the remote to synchronize CREATE PUBLICATION "routing" ( TABLE routing, TABLE proposal( prop_id, prop_text, last_modified ) ); Each publication can contain many tables Column list is optional

38 Subscription A subscription does the following Uniquely identifies the remote Supplies the “address” of the MobiLink server Supplies the “protocol” that will be used to synchronize Supplies any extended options for the remote CREATE SYNCHRONIZATION USER "50"; CREATE SYNCHRONIZATION SUBSCRIPTION TO "routing" FOR "50" TYPE 'tcpip' ADDRESS 'host=localhost;port=2439' OPTION ScriptVersion='v1.0';

39 DBMLSync Options In order for scripts to be generated DBMLSync must send the column names to MobiLink Column names are normally not required Increase the communications overhead DBMLSync must have an extended option enabled (first time only) SendColumnNames=‘Yes’

40 Setup DBMLSync These commands are run against the remote database CREATE PUBLICATION "routing" ( TABLE routing, TABLE proposal( prop_id, prop_text, last_modified ) ); CREATE SYNCHRONIZATION USER "50"; CREATE SYNCHRONIZATION SUBSCRIPTION TO "routing" FOR "50" TYPE 'tcpip' ADDRESS 'host=localhost;port=2439' OPTION ScriptVersion='v1.0', SendColumnNames='Yes';

41 Run DBMLSync MobiLink has been setup to automatically generate scripts (-za+) DBMLSync initiates a synchronization DBMLSync sends extra information, including column names DBMLSync -c DSN=remote -ot rem.txt MobiLink will Generate the scripts based on this information Synchronize using the scripts it just generated

42 Generated Scripts View with Sybase Central – MobiLink Synchronization Server Plugin

43 Generated Scripts The automatically generated scripts Download_cursor SELECT prop_id, prop_text, last_modified FROM proposal Upload_insert INSERT INTO proposal( prop_id, prop_text, last_modified )VALUES( ?, ?, ? ) Upload_delete DELETE FROM proposal WHERE prop_id = ? Upload_update UPDATE proposal SET prop_text = ?, last_modified = ? WHERE prop_id = ?

44 The Task - Complete Get it synchronizing in 10 minutes Did we do it? Easy as Schema migration Script generation Initial synchronization

45 Topics Synchronization The Task Database Migration Generating MobiLink Scripts Script Customization Remote Monitoring

46 All Rows Generated download_cursors are of this format SELECT prop_id, prop_text, last_modified FROM proposal Assume 1000 rows in the table If a user synchronizes a second time Select will return all 1000 rows (no WHERE clause) 1000 rows will be downloaded again DBMLSync/Ultralite will update the existing values Very inefficient

47 Timestamp Based Requirement In order to download ONLY the rows that have changed since the remote last synchronized we need A column on the table indicating the last time the row was modified This column must be maintained by the database or application Last time the user synchronized

48 Last_modified Column Each table in the consolidated database requires a column indicating when the row was last changed In ASA, you can create the column like this Last_modified TIMESTAMP DEFAULT TIMESTAMP The database engine will automatically maintain this column for you In other RDBMS Triggers are often required

49 LastDownload Time New to Vail (8.0) The remote will now maintain the LastDownload time automatically The remote will send this value to MobiLink as part of the synchronization MobiLink supplies this value to the scripts MobiLink automatically updates this value The updated value will be included as part of the download If the remote successfully receives the download, it also has the updated time If the download fails, the old value will be uploaded and no data will be missed

50 Initial LastDownload Time If the remote has never synchronized before The initial value for the LastDownload time is ‘1900/01/01 00:00’

51 Timestamp Based Synchronization Each download_cursor script is passed 2 parameters Synchronizing User Name Last Download Timestamp for that user Download scripts can be modified SELECT order_id, … FROM ULOrder WHERE emp_id = ? AND last_modified >= ?

52 Timestamp Based Synchronization If your download_cursor does not require the user name SELECT cust_id, … FROM ULCustomer WHERE ? IS NOT NULL AND last_modified >= ? The “? IS NOT NULL” is used as a place holder, since the second “?” is always the LastDownload time

53 Timestamp Based With ASA begin_connection create integer; create timestamp begin_download CALL )

54 SetParameters CREATE PROCEDURE SetParameters( INsync_user_nameVARCHAR(40), INlast_downloadTIMESTAMP, OUTo_sync_user_nameVARCHAR(40), OUTo_last_downloadTIMESTAMP ) BEGIN set o_sync_user_name = sync_user_name; set o_last_download = last_download; END;

55 Timestamp Based with Variables If your download_cursor with variables SELECT cust_id, … FROM ULCustomer WHERE last_modified There are always many ways to do the same thing Depends on the features of your consolidated RDBMS Your preferences / standards

56 LastDownload Time In version 7.x The LastDownload time was NOT automatically provided YOU had to maintain this value in a user table It was retrieved in the begin_download event for the current synchronization It was updated in the begin_download event (after retrieval) This was an uncommitted transaction UNTIL MobiLink received a confirmation from the remote

57 Download Acknowledgement By default MobiLink will wait for the remote to acknowledge the download BEFORE committing the download Now that Vail manages the LastDownload date, this is normally no longer required To turn off use Extended option – SendDownloadAck = ‘No’ Ultralite ul_synch_info.send_download_ack = false I recommend turning this off

58 Topics Synchronization The Task Database Migration Generating MobiLink Scripts Script Customization Remote Monitoring

59 Remote Monitoring Consider a project with 1000 deployed remote users How can you (the administrator) be certain all 1000 users are synchronizing without problems If there are problems How can you research it? What information is available? How can you capture more information?

Default Error Handling Default behaviour If a SQL error occurs while MobiLink is accessing the consolidated database handle_error event is fired report_error event is fired Current transaction is rolled back All rows affected by the upload OR All rows affected by the download Synchronization session is ended Remote receives a error

61 Custom Error Handling You can choose to handle the error handle_error connection level event Stored procedure call Requires a number of parameters The return code from the stored procedure instructs MobiLink Ignore error OR Stop the synchronization request OR Stop the MobiLink server I do not recommend handling the error Design to prevent errors instead

62 Error Reporting report_error script Uses same parameters as handle_error (minimally) Executed on a separate connection Logging/auditing is committed outside of the upload/download transaction Therefore the action is permanent I highly recommend the use of the report_error

Error Handling Scripts CREATE TABLE sync_error_audit ( idint DEFAULT autoincrement, sync_uservarchar(128), table_namevarchar(128), error_msglong varchar, error_datedatetime DEFAULT current timestamp, primary key( id ) ); call ml_add_connection_script('version', 'report_error', 'CALL MLReportError( ?, ?, ?, ?, ? )' );

64 Error Logging CREATE PROCEDURE MLReportError( IN actioninteger, IN error_codeinteger, IN error_messagevarchar(1000), IN user_namevarchar(128), IN in_table_namevarchar(128) ) BEGIN INSERT INTO sync_error_audit( sync_user, table_name, error_msg ) VALUES( user_name, in_table_name, error_message ) END;

65 Automated Notifications Many databases support interfaces (ASA, ASE, Microsoft at least) The MLReportError procedure could be enhance to automatically an administrator (or group) of the error Syntax/Names may vary for different RDBMS Java Synchronization Logic can also be used with JavaMail to achieve the same effect

66 Sample DECLARE rc INTEGER; rc=call xp_startmail(mail_user=‘MobiLink_Administrator'); //If successful logon to mail IF rc=0 THEN rc=call xp_sendmail(recipient='MobiLink_Notification_Group', subject='MobiLink Synchronization Error: '+user_name, "message"=error_msg); //If mail sent successfully IF rc=0 THEN call xp_stopmail() END IF

67 Capturing Remote Logs If errors occur during synchronization it is often useful to view the remote DBMLSync log The log is on a remote machine, so how does the administrator get access to it? The user must be contacted Must locate the file Mail it to the administrator Or some other mechanism (Remote control…)

68 Capturing Remote Logs MobiLink has a special provision for this -e(t) file_name If an error occurs during synchronization, the remote will send its DBMLSync log to MobiLink MobiLink will store the remote log in this file If used with the automated notifications, an administrator should be well “armed” to research the problem

69 DBMLSync Options In order for DBMLSync to send the logs to MobiLink an extended option must be enabled SendOutputLogOnError=‘Yes’ CREATE SYNCHRONIZATION SUBSCRIPTION TO "routing" FOR "50" TYPE 'tcpip' ADDRESS 'host=localhost;port=2439' OPTION ScriptVersion='v1.0', SendDownloadAck='No', SendOutputLogOnError='Yes';

70 Summary Database migration is very useful for creating remote database schemas fast and effectively Script generation can save a great deal of time initially Scripts must be customized LastDownload functionality should be added as a minimum

71 Summary Remote Monitoring should always be considered in any distributed environment Consider ways to automate notifications Java can be used to extend that to pages and so on Any effort taken at the outset can save a great deal of time and effort if a problem arises EM403 MobiLink Best Design Practices

72 Newsgroups forums.sybase.com sybase.public.sqlanywhere.general sybase.public.sqlanywhere.linux sybase.public.sqlanywhere.mobilink sybase.public.sqlanywhere.product_futures_discussion sybase.public.sqlanywhere.replication sybase.public.sqlanywhere.ultralite Questions?

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