Embed Size (px)
Citation preview
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
SynchronizationThe TaskDatabase MigrationGenerating MobiLink ScriptsScript CustomizationRemote 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 technologiesReplication Server
SQL Remote (for ASE and ASA)
5
Replication Server Architecture
Rep Server
ASE
ASE LTM
ASE
DBSRV6
DBLTM
ASA
MAPI VIM
FILE
FTP SMTP
ASA
Other
ORACLE
DB2
6
SQL Remote
ASE
MAPI VIM
FILE
FTP SMTP
ASA
ASA
MAPI VIM
FILE
FTP SMTP
ASA
OR
7
SQL Remote with Replication Server
Rep Server
ASE
ASE LTM SSQueue
MAPI VIM
FILE
FTP SMTP
ASA
8
MobiLink
ASA, ASE, Microsoft, Oracle, IBM
ASA, PalmOS, PocketPC, UltraLite
HTTP, TCPIP HotSync, WirelessSerial
9
MobiLink and SQL Remote
ASA, ASE
ASA, Palm, CE, Pagers, Phones
SQL Remote MobiLink
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
DownloadA table at a time
12
Synchronization Transactions
Upload streamChanges from the remote are applied to the consolidated,
followed by a commit
Summary of changes
Download streamData 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 controlWhat 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
SynchronizationThe TaskDatabase MigrationGenerating MobiLink ScriptsScript Customization Remote Monitoring
15
The Task
Tips are best learned when we have a task to accomplishStart 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 schemaIn my experience this is true most of the time
If the consolidate and remote have different schemasThis is still expected
Customization of the MobiLink scripts will be required
• MobiLink was designed for these cases as well
17
Topics
SynchronizationThe TaskDatabase MigrationGenerating MobiLink ScriptsScript Customization Remote Monitoring
18
Consolidated Database
Lets assume your consolidated database is Microsoft SQL ServerIt could just as easily be Oracle
Remote database must be Adaptive Server Anywhere (ASA)
UltraLite
Compatible ASA schema must be createdRequired 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 databaseUse 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 statements1. 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 migrateSchema
Data (optional)
Proceduredbo.sa_migrate(
IN local_table_owner VARCHAR(128),
IN server_name VARCHAR(128),
IN table_name VARCHAR(128) DEFAULT NULL,
IN owner_name VARCHAR(128) DEFAULT NULL,
IN database_name VARCHAR(128) DEFAULT NULL,
IN migrate_data BIT DEFAULT 1,
IN drop_proxy_tables BIT DEFAULT 1)
24
Procedure sa_migrate()
CALL sa_migrate( 'DBA', 'mss_cons', 'UL%', 'dbo', 'CustDB', 0, 1 );DBA Create the tables under the DBA owner
(ASA)
mss_cons ASA Remote Server
UL% Only create the tables that begin with ‘UL’
dbo MSS owner of the tables
CustDB Which MSS database (there can be many)
0 Do not migrate data
1 Drop the proxy tables when finished
25
Verify Results
Check only UL% tables were createdEnsure no data was migrated
26
Database Migration (Long way)
Sometimes you need more flexibility when migrating the schemaNo convenient ‘UL%’ for the tables you need
Errors during the migration process
6 stored procedures can be used instead1. 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
SynchronizationThe TaskDatabase MigrationGenerating MobiLink ScriptsScript Customization Remote Monitoring
29
Script Versions
MobiLink scripts are organized by script versionUse any naming convention you likeHave 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 usingStandard 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_insertUpload_deleteUpload_updateDownload_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 proneThe 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 switchDBMLSRV8 –vcrsnNormally use this when creating scripts c – show the content of each script as it is executedr – show the column values for each of the rows uploaded and
downloadeds – show the name of the event that is firedn – show the row count summaries
36
DBMLSync
MobiLink clientInitiates synchronization with MobiLinkDBMLSync 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 synchronizeCREATE PUBLICATION "routing" (
TABLE routing,
TABLE proposal( prop_id, prop_text, last_modified )
);
Each publication can contain many tablesColumn list is optional
38
Subscription
A subscription does the followingUniquely 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 MobiLinkColumn 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 synchronizationDBMLSync sends extra information, including
column namesDBMLSync -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 scriptsDownload_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 1-2-3
• Schema migration
• Script generation
• Initial synchronization
45
Topics
SynchronizationThe TaskDatabase MigrationGenerating MobiLink ScriptsScript CustomizationRemote Monitoring
46
All Rows
Generated download_cursors are of this format• SELECT prop_id, prop_text, last_modified FROM
proposalAssume 1000 rows in the tableIf 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 needA 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 changedIn 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 beforeThe initial value for the LastDownload time is
• ‘1900/01/01 00:00’
51
Timestamp Based Synchronization
Each download_cursor script is passed 2 parametersSynchronizing User Name
Last Download Timestamp for that user
Download scripts can be modifiedSELECT 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_connectioncreate variable @EmployeeID integer;
create variable @LastDownload timestamp
begin_downloadCALL SetParameters(?, ?, @EmployeeID, @LastDownload )
54
SetParameters
CREATE PROCEDURE SetParameters( IN sync_user_name VARCHAR(40), IN last_download TIMESTAMP, OUT o_sync_user_name VARCHAR(40), OUT o_last_download TIMESTAMP )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 variablesSELECT cust_id, …
FROM ULCustomer
WHERE last_modified >= @LastDownload
There are always many ways to do the same thingDepends on the features of your consolidated RDBMS
Your preferences / standards
56
LastDownload Time
In version 7.xThe 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 downloadNow 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
SynchronizationThe TaskDatabase MigrationGenerating MobiLink ScriptsScript Customization Remote Monitoring
59
Remote Monitoring
Consider a project with 1000 deployed remote usersHow 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 behaviourIf 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 errorhandle_error connection level eventStored procedure call
• Requires a number of parametersThe return code from the stored procedure instructs MobiLink
• 1000 - Ignore error OR• 3000 - Stop the synchronization request OR• 4000 - Stop the MobiLink server
I do not recommend handling the errorDesign to prevent errors instead
62
Error Reporting
report_error scriptUses 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 ( id int DEFAULT autoincrement, sync_user varchar(128), table_name varchar(128), error_msg long varchar, error_date datetime DEFAULT current timestamp, primary key( id ));
call ml_add_connection_script('version', 'report_error','CALL MLReportError( ?, ?, ?, ?, ? )' );
64
Error Logging
CREATE PROCEDURE MLReportError( IN action integer, IN error_code integer, IN error_message varchar(1000), IN user_name varchar(128), IN in_table_name varchar(128) )BEGININSERT 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 email interfaces (ASA, ASE, Microsoft at least)
The MLReportError procedure could be enhance to automatically email an administrator (or group) of the error
Syntax/Names may vary for different RDBMSJava Synchronization Logic can also be used with JavaMail
to achieve the same effect
66
Email Sample
DECLARE rc INTEGER;rc=call xp_startmail(mail_user=‘MobiLink_Administrator');
//If successful logon to mailIF 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
END IF
67
Capturing Remote Logs
If errors occur during synchronization it is often useful to view the remote DBMLSync logThe 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 enabledSendOutputLogOnError=‘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 initiallyScripts must be customized
LastDownload functionality should be added as a minimum
71
Summary
Remote Monitoring should always be considered in any distributed environmentConsider ways to automate notifications
• Java can be used to extend that to email 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.comsybase.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?
73
iAnywhere Solutions Highlights
• Ask the Experts - about Mobile & Wireless Solutions-Mezzanine Level Room 15B Mon./Tues. 11:30 am - 3:30 pm; Wed. 11:30 - 1:30;Thurs. 9 am - 12 noon-Exhibit Hall - Demo Center (truck) exhibit hall hours
• SIG (Special Interest Group)- Tuesday 5:30pm Mobile & Wireless SDCC, Upper level, Room 11
• Keynote - Enabling m-Business SolutionsWednesday 1:30 pm - 3:00 pm
• iAnywhere Solutions Developer Community-Excellent resource for commonly asked questions, newsgroups, bugfixes, newsletters, event listings - visit www.ianywhere.com/developer
