Replication Server Presentation - Sybase

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Replication Server Presentation - Sybase

Why Replicate?• High Availability of data• Planned, Unplanned downtime and Disaster Recovery• Data Distribution• Decentralizations• Consolidations• Load balancing• Live decision support• Separation of OLTP and DSS


Replication and High AvailabilityPhiladelphia OperationsASEPRIMARY DATACENTERDenver OperationsASEReplicationServerReplicationServerSECONDARY DATACENTERWarm Standby•Minimize/eliminate user impact•Protect against unplannedoutages•Software, Hardware,Application failure•Unforeseen circumstances likedata corruption•Protect against planned outages•Software, Hardware,Application upgrades•Enable ops to performmaintenance activities•Recover from natural disaster•Without geographic restrictions


Replication System Architecture: Warm StandbyActive DBAdd’l routes/connectionsLogical DBStandby DBRS• Special Configuration: One Active,One Standby Database managed byOne Rep Server• May be configured to replicate theentire database – Complete Mirror!(publish-subscribe mechanism notrequired)• DDL/Schema Change replication!• Direction of Replication can beswitched• Performs failover and failback• Ease of Administration, Low latency• Active-Standby pair viewed as asingle logical DB at other replicatesites


Replication and Data Distribution• Continuous SecureReplication ofchanged dataCRM-sales, customerFinancial InformationDealersDealers• GuaranteedDeliveryASERep ServerASERep ServerFor• Decentralization• Consolidation• Load BalancingASERep ServerNew York ConsolidationASERep ServerASERep Server


Replication and Live Decision Support• Separate Operational data from Decision Support• Run intensive queries without effecting theperformance of transaction processing system• Real-time alternative to Data WarehousingOLTPDSSASE Rep Server Rep Server ASE


Requirements for e-Business Data Movement• Increasing demand for assurance of privacy• Solution: Secure, guaranteed replication for datadistribution• Flexibility in moving data around the enterprise• Solution: Support replication of e-business data acrossheterogeneous databases• 24/7 system availability• Solution: High Performance Data Replication throughReplication Server Warm Standby


Replication Server 12.5: New FeaturesNew Features• Security• Advanced Security Option – SSL Support• Flexibility• Unicode Support• LDAP Support• Extended Limits Data Support• Multi-Vendor Replication• Performance• Configurable Transaction Partitioning for Parallel DSI• SMP Support• Commit Sequencing Enhancements for Parallel DSI


Security - SSL SupportBackground• SSL – Secure Socket Layer – is an industry standard forsending socket-level encrypted data over networkconnections• Different Encryption algorithms can be used for datasecurity• Data integrity is guaranteed through Digital Signatures fortamper protection and non-repudiation• Mutual authentication of servers and clients through DigitalCertificates• Typically for communications over a wide area network• The computing overhead of encryption limits its use in LANenvironments behind the firewall


Security - Advanced Security Option – SSL• Replication Server provides advanced security for datacommunications through SSL Support• All data exchanges with other servers (ASE or RS) canuse SSL for data encryption• SSL can be used selectively on specific connections orroutes• SSL Support is a separately license-able optionRouteDSIRepAgentRSSSL SSL SSL


Security - SSL Support• Replication Server can act as a client and a server forSSL communication• Acts as a client when connecting to ASE (DSIconnections) or to other Replication Servers (routes)• Acts as a server when accepting connections fromReplication Agent or from other Replication Servers(routes)• A configuration parameter determines whetherReplication Server can accept SSL connections• The parameter determines its behavior as a server, notas a client• configure replication server set use_ssl to {on | off}


Security - SSL Support• The interfaces file entry indicates to the client that theserver requires SSL connections• If the target (ASE or RS) requires SSL communication(through the interface entries), the client automaticallyuses SSL to connect• Different clients can use or not use SSL to connect to thesame server using different interface files• SSL incurs considerable overhead at connection setupWAN/InternetSSLSSLLondon RSRouteInterface file with SSL Entryfor NYRSNYRSNJRSInterface file with plainEntry for NYRS


Security - SSL SupportPrevent interception of sensitive information• SSL Encryption protects from both accidentaldisclosure as well as wire taps• PKI-certificates authenticate servers to clients• Fully embedded in product, reducing complexity toclient applications• Complete end-to-end security services support for ASEreplication environment


Flexibility - Unicode Support• Replication Server 12.5 supports utf8 character set asa default character set for the server• Greatly benefits global environments with multiplelanguages and character sets• By running all Replication Servers in the environmentwith utf8 character set, you minimize data conversionsand thereby, minimize data lossJapanoperationsASE RS ASE RSNo data conversion, no data lossGermanoperationsASE RSNew York Consolidation


Flexibility - Unicode Support• Supports replication of Unicode data (UCS-2)• Supports replication of two new ASE 12.5 data types: unichar,univarchar• Unichar is a fixed-width non-nullable data type• Univarchar is a variable width, nullable data type• Both use UTF-16, a fixed two-byte encoding of Unicode• Support includes:• Replication to Standby databases• Replication to Replicate databases• Data types can be included in replication definitions• As searchable columns (subscriptions can use them inwhere clauses)


Flexibility - Unicode Support• Replication of Unicode data• Different sort order used for Unicode data (unichar,univarchar columns), defined by the newRS_unicode_sortorder parameter in the configuration file(default: binary)• RS_subcmp supports the unicode data types• Mixed Version Support• Replication Definition that includes unicode data types isnot propagated to pre-12.5 servers (dropped from pre-12.5 servers if it already exists)• Replication Definition that is subscribed by pre-12.5servers can not be altered to include unicode data types


Flexibility - LDAP Support• Allows Replication Server to retrieve Server connectioninformation from an LDAP server• Ease of administration in distributed, enterprise-wideenvironments with heterogeneous platforms• A standard, central wayof managing directoryinformation canbe supported inreplicationenvironmentsLDAP DirectoryASE RS ASE RSASERS


Flexibility - Extended Limits Data Support• Complete support for replication of extended limits data– wide columns, wide tables, wide stored proceduresetc.• Column widths up to 32K bytes• Tables up to 1024 columns• Stored Procedures up to 1024 parameters• Internal limitation of replication message length of 16Kbytes eliminated• Support for larger page sizes in ASE (2K, 4K, 8K or 16K)


Flexibility - Extended Limits Data Support• Replication Definition can include• Wider columns (up to 32K bytes) and up to 1024 cols• Can be marked as primary columns or searchable cols• No limit (up to 1024) on the number of columns inprimary key or searchable list• Only propagated to 12.5 sites if new limits are used• Before 12.5, Replication Message length (length ofeach message passed between ASE-RS and RS-RS)had to be below 16K bytes (fit within a Stable Queueblock)• Starting with 12.5, replication messages can spanmultiple blocks• Replication of wider column data is likely to result inwider replication messages


Flexibility - Extended Limits Data SupportMixed Version Support• ASE Replication Agent will detect if the ReplicationServer can handle wide data• If not, Replication Agent will truncate or skip the data (asconfigured) before sending it over to Replication Server• “Route Version” will determine if wide data can behandled by Replication Servers at either end of theroute• Replication Server will skip over any messages that arelarger than the 16K limit before sending data over toother Replication Servers that can’t handle wide data• Replication Definitions that contain wide columns are notpropagated to sites that can’t handle wide data, hencereplication to older sites is limited to older limits


Flexibility - Extended Limits Data SupportMigration• Replication Server can be used in conjunction with theASE Migration Tool to migrate between databases ofdifferent page sizes over a period of time• Migration Tool can be used to setup the secondarycopy, while Replication Server can keep the copies insynch, such that migration occurs over a period of timeand applications can be fully tested• The same technique (with dump/load) can be used tomigrate from one server version to another (or acombination of version and page size change) withalmost no downtime


Flexibility - Multi-Vendor ReplicationPrimary DB(Oracle)RSAdd’l routes/connectionsRep Agentfor Oracle• Replication Agents pull dataout of non-Sybase sources• DirectConnects are used asgateways to replicate intonon-Sybase targets• Support for vendor-specificdatatypes, translations etc.Replicate DB(MS SQL)DirectConnectfor MS SQL• Some Replication Agentsread the transaction log(DB2), some build a virtuallog with triggers (Oracle,MS SQL)


Flexibility - Heterogeneous Replication• Extended Limits Data• Wide data (columns, tables and stored procedures) canbe replicated between multi-vendor databases – ASE,Oracle, DB2 etc.• Replication Agent, DirectConnect supports replication ofwide data• LOB (Text/Image) Data• Replication Agent now supports LOB replication out ofDB2 UDB• LOB support by Direct Connect for Oracle allows end-toendreplication of text/image data for Oracleenvironments


Flexibility - Heterogeneous Replication• Unicode• Unicode data can be replicated between multi-vendordatabases• Replication Agent and Direct Connect for Oracle supportreplication of unicode data and UTF-8 character set• Platform Support• Oracle 8.1.7 and 9i (Replication Agent, Direct Connect)• IBM DB2 UDB 6.1, 7.1 and 7.2 (RA, DC)• SQL Server 7.0 and 2000 (aka 8.0) (RA, DC):Replication Agent is now available on Unix and Windows2000• Informix 7.3 and 9.2 (RA, DC)


Replication Server PackagingReplicationServerBasePackageReplication Server Base Server LicenseReplication Server ManagerSybase Central Plug-in forReplication ServerReplication Server - Advanced Security OptionOption forOracleOption forInformixOption forMicrosoftOption forDB2/UDBRARARARAReplicationServerOptionsPackageDCDCDCDCASEASEASEASE


Replication Server 12.5Performance Enhancements• Configurable Transaction Partitioning for Parallel DSI• SMP Support – Will be released in an EBF 3-4 months• Commit Sequencing Enhancements for Parallel DSI –Will be released in an EBF 3-4 months


Performance EnhancementsConfigurable Transaction PartitioningBackground• Parallel DSI threads in RS attempt to apply transactions inthe queue to the replicate DB in parallel• Each DSI thread opens a connection to the replicate DB• Commit order is still maintained – only the “body” of thetransactions are applied in parallel• Transactions can also be grouped together to apply “more”in each unit of work – grouping rules decide whichtransactions can be grouped• Not all transaction “bodies” can be applied in parallel• Some of them may deal with the same tables/rows• Resulting in deadlocks and rollbacks, reducingthroughput• Transaction grouping increases the chance of contention


Performance EnhancementsConfigurable Transaction Partitioning• Traditional Transaction Partitioning• The transactions (transaction groups) are partitionedacross DSI threads in a round robin fashionQueueT3T2T1T1T2T3• Possibility of deadlocks or contention if transactions(groups) assigned to different threads work on the sametables or rows• Both transactions are rolled back and applied serially if adeadlock is detected


Performance EnhancementsConfigurable Transaction Partitioning• Configurable Transaction Partitioning• The transactions are grouped and partitioned across DSIthreads intelligently based on transaction attributes(configurable)• The goal is to reduce contention by recognizing whichtransactions can be applied in parallel and whichtransactions can be grouped• Transaction commit time, Transaction name and Username are used to determine how transactions can bepartitionedQueueT3T2T1T1, T2T4, T5T3Tran Partitioning Rules Engine


Performance EnhancementsConfigurable Transaction Partitioning• Username Based Transaction Partitioning• Transactions owned by the same user are forced to executeserially (possibly in the same transaction group) since theywere probably executed one after the other at the primary bythe same user• Transaction Name Based Transaction Partitioning• Transactions with the same name are forced to executeserially (possibly in the same transaction group) since theyprobably represent operations on related data and might leadto contention if attempted in parallel• Commit Time based Transaction Partitioning• Transactions that have overlapping execution times areassigned to (different groups and) parallel threads since theywere applied concurrently at the primary – less chance forcontention


Performance EnhancementsConfigurable Transaction Partitioning• Replication Server attempts to mimic users at primaryDB• Brings replicate throughput closer to primary DBthroughput• Reduces contention among multiple RS threads (DSI)applying transactions at the replicate DB• Optimal resource utilization by minimizing deadlocks androllbacks• Parallel DSI Processing is made more efficient byreducing the contention and deadlocks in the replicateDB


Performance EnhancementsSMP Support• Takes advantage of SMP architecture and improvesscalability• Parallelizing internal Replication Server processingdecreases latency and increases throughput• Scales well for replication of multiple sources andtargets within the same server


Performance EnhancementsSMP Support• Replication Server will utilize multiple processors on themachine• Built on SMP Open Server• Based on a threading model rather than an engine model• Uses OS Native threads in pre-emptive mode• Server spawns numerous cooperating threads that runconcurrently• Number of CPUs used by the server can be controlled bybinding the CPUs to the server using OS-specificmechanisms• e.g., psrset/pbind on Solaris• Server can be forced into a single processor mode usinga switch• configure replication server set smp_enable to {on | off}


Performance EnhancementsCommit Sequencing EnhancementsBackground• Parallel DSI threads in RS attempt to applytransactions in the queue to the replicate DB in parallel• Commit order is still maintained – only the “body” of thetransactions are applied in parallel• Replication Server relies on a table in the replicate DB(rs_threads) to detect deadlocks and help sequencecommits• Additional overhead on the replicate DB• Additional network roundtrips (between RS and replicateDB) for each transaction (group)• Limits the usability of Parallel DSI to ASE environments


Performance EnhancementsCommit Sequencing EnhancementsInternal Commit Sequencing• Deadlock detection for transactions distributed acrossParallel DSI threads is now done internally inReplication Server• Commit sequencing is now completely internal to RS• Eliminates a network roundtrip for each transaction –reduced I/O• Less overhead for each transaction (group) – fastercommit processing• Removes the reliance on replicate DB• Eliminates a bottleneck (rs_threads) in the replicate DB• Allows non-ASE environments to take advantage of theParallel DSI feature


Summary• The e-Business data management platform• Sybase fundamentals: open, flexible, secure,high-performance, high availability• New enhancements to support evolution to e-Business• e-Business Security• Protecting valuable information• High Availability• Ensures data is available when needed• Dynamic Performance• Ensuring your mission-critical information is availablewhere needed

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