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 Availability
Philadelphia Operations
ASE
PRIMARY DATACENTER
Denver Operations
ASE
Replication
Server
Replication
Server
SECONDARY DATACENTER
Warm Standby
•Minimize/eliminate user impact
•Protect against unplanned
outages
•Software, Hardware,
Application failure
•Unforeseen circumstances like
data corruption
•Protect against planned outages
•Software, Hardware,
Application upgrades
•Enable ops to perform
maintenance activities
•Recover from natural disaster
•Without geographic restrictions

Replication System Architecture: Warm Standby
Active DB
Add’l routes/
connections
Logical DB
Standby DB
RS
• Special Configuration: One Active,
One Standby Database managed by
One Rep Server
• May be configured to replicate the
entire database – Complete Mirror!
(publish-subscribe mechanism not
required)
• DDL/Schema Change replication!
• Direction of Replication can be
switched
• Performs failover and failback
• Ease of Administration, Low latency
• Active-Standby pair viewed as a
single logical DB at other replicate
sites

Replication and Data Distribution
• Continuous Secure
Replication of
changed data
CRM-sales, customer
Financial Information
Dealers
Dealers
• Guaranteed
Delivery
ASE
Rep Server
ASE
Rep Server
For
• Decentralization
• Consolidation
• Load Balancing
ASE
Rep Server
New York Consolidation
ASE
Rep Server
ASE
Rep Server

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

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

Replication Server 12.5: New Features
New 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 Support
Background
• SSL – Secure Socket Layer – is an industry standard for
sending socket-level encrypted data over network
connections
• Different Encryption algorithms can be used for data
security
• Data integrity is guaranteed through Digital Signatures for
tamper protection and non-repudiation
• Mutual authentication of servers and clients through Digital
Certificates
• Typically for communications over a wide area network
• The computing overhead of encryption limits its use in LAN
environments behind the firewall

Security - Advanced Security Option – SSL
• Replication Server provides advanced security for data
communications through SSL Support
• All data exchanges with other servers (ASE or RS) can
use SSL for data encryption
• SSL can be used selectively on specific connections or
routes
• SSL Support is a separately license-able option
Route
DSI
RepAgent
RS
SSL SSL SSL

Security - SSL Support
• Replication Server can act as a client and a server for
SSL communication
• Acts as a client when connecting to ASE (DSI
connections) or to other Replication Servers (routes)
• Acts as a server when accepting connections from
Replication Agent or from other Replication Servers
(routes)
• A configuration parameter determines whether
Replication Server can accept SSL connections
• The parameter determines its behavior as a server, not
as a client
• configure replication server set use_ssl to {on | off}

Security - SSL Support
• The interfaces file entry indicates to the client that the
server requires SSL connections
• If the target (ASE or RS) requires SSL communication
(through the interface entries), the client automatically
uses SSL to connect
• Different clients can use or not use SSL to connect to the
same server using different interface files
• SSL incurs considerable overhead at connection setup
WAN/Internet
SSL
SSL
London RS
Route
Interface file with SSL Entry
for NYRS
NYRS
NJRS
Interface file with plain
Entry for NYRS

Security - SSL Support
Prevent interception of sensitive information
• SSL Encryption protects from both accidental
disclosure as well as wire taps
• PKI-certificates authenticate servers to clients
• Fully embedded in product, reducing complexity to
client applications
• Complete end-to-end security services support for ASE
replication environment

Flexibility - Unicode Support
• Replication Server 12.5 supports utf8 character set as
a default character set for the server
• Greatly benefits global environments with multiple
languages and character sets
• By running all Replication Servers in the environment
with utf8 character set, you minimize data conversions
and thereby, minimize data loss
Japan
operations
ASE RS ASE RS
No data conversion, no data loss
German
operations
ASE RS
New 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 in
where clauses)

Flexibility - Unicode Support
• Replication of Unicode data
• Different sort order used for Unicode data (unichar,
univarchar columns), defined by the new
RS_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 is
not propagated to pre-12.5 servers (dropped from pre-
12.5 servers if it already exists)
• Replication Definition that is subscribed by pre-12.5
servers can not be altered to include unicode data types

Flexibility - LDAP Support
• Allows Replication Server to retrieve Server connection
information from an LDAP server
• Ease of administration in distributed, enterprise-wide
environments with heterogeneous platforms
• A standard, central way
of managing directory
information can
be supported in
replication
environments
LDAP Directory
ASE RS ASE RS
ASE
RS

Flexibility - Extended Limits Data Support
• Complete support for replication of extended limits data
– wide columns, wide tables, wide stored procedures
etc.
• Column widths up to 32K bytes
• Tables up to 1024 columns
• Stored Procedures up to 1024 parameters
• Internal limitation of replication message length of 16K
bytes 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 in
primary key or searchable list
• Only propagated to 12.5 sites if new limits are used
• Before 12.5, Replication Message length (length of
each message passed between ASE-RS and RS-RS)
had to be below 16K bytes (fit within a Stable Queue
block)
• Starting with 12.5, replication messages can span
multiple blocks
• Replication of wider column data is likely to result in
wider replication messages

Flexibility - Extended Limits Data Support
Mixed Version Support
• ASE Replication Agent will detect if the Replication
Server can handle wide data
• If not, Replication Agent will truncate or skip the data (as
configured) before sending it over to Replication Server
• “Route Version” will determine if wide data can be
handled by Replication Servers at either end of the
route
• Replication Server will skip over any messages that are
larger than the 16K limit before sending data over to
other Replication Servers that can’t handle wide data
• Replication Definitions that contain wide columns are not
propagated to sites that can’t handle wide data, hence
replication to older sites is limited to older limits

Flexibility - Extended Limits Data Support
Migration
• Replication Server can be used in conjunction with the
ASE Migration Tool to migrate between databases of
different page sizes over a period of time
• Migration Tool can be used to setup the secondary
copy, while Replication Server can keep the copies in
synch, such that migration occurs over a period of time
and applications can be fully tested
• The same technique (with dump/load) can be used to
migrate from one server version to another (or a
combination of version and page size change) with
almost no downtime

Flexibility - Multi-Vendor Replication
Primary DB
(Oracle)
RS
Add’l routes/
connections
Rep Agent
for Oracle
• Replication Agents pull data
out of non-Sybase sources
• DirectConnects are used as
gateways to replicate into
non-Sybase targets
• Support for vendor-specific
datatypes, translations etc.
Replicate DB
(MS SQL)
DirectConnect
for MS SQL
• Some Replication Agents
read the transaction log
(DB2), some build a virtual
log with triggers (Oracle,
MS SQL)

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

Flexibility - Heterogeneous Replication
• Unicode
• Unicode data can be replicated between multi-vendor
databases
• Replication Agent and Direct Connect for Oracle support
replication 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 Windows
2000
• Informix 7.3 and 9.2 (RA, DC)

Replication Server Packaging
Replication
Server
Base
Package
Replication Server Base Server License
Replication Server Manager
Sybase Central Plug-in for
Replication Server
Replication Server - Advanced Security Option
Option for
Oracle
Option for
Informix
Option for
Microsoft
Option for
DB2/UDB
RA
RA
RA
RA
Replication
Server
Options
Package
DC
DC
DC
DC
ASE
ASE
ASE
ASE

Replication Server 12.5
Performance 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 Enhancements
Configurable Transaction Partitioning
Background
• Parallel DSI threads in RS attempt to apply transactions in
the 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 the
transactions are applied in parallel
• Transactions can also be grouped together to apply “more”
in each unit of work – grouping rules decide which
transactions 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, reducing
throughput
• Transaction grouping increases the chance of contention

Performance Enhancements
Configurable Transaction Partitioning
• Traditional Transaction Partitioning
• The transactions (transaction groups) are partitioned
across DSI threads in a round robin fashion
Queue
T3
T2
T1
T1
T2
T3
• Possibility of deadlocks or contention if transactions
(groups) assigned to different threads work on the same
tables or rows
• Both transactions are rolled back and applied serially if a
deadlock is detected

Performance Enhancements
Configurable Transaction Partitioning
• Configurable Transaction Partitioning
• The transactions are grouped and partitioned across DSI
threads intelligently based on transaction attributes
(configurable)
• The goal is to reduce contention by recognizing which
transactions can be applied in parallel and which
transactions can be grouped
• Transaction commit time, Transaction name and User
name are used to determine how transactions can be
partitioned
Queue
T3
T2
T1
T1, T2
T4, T5
T3
Tran Partitioning Rules Engine

Performance Enhancements
Configurable Transaction Partitioning
• Username Based Transaction Partitioning
• Transactions owned by the same user are forced to execute
serially (possibly in the same transaction group) since they
were probably executed one after the other at the primary by
the same user
• Transaction Name Based Transaction Partitioning
• Transactions with the same name are forced to execute
serially (possibly in the same transaction group) since they
probably represent operations on related data and might lead
to contention if attempted in parallel
• Commit Time based Transaction Partitioning
• Transactions that have overlapping execution times are
assigned to (different groups and) parallel threads since they
were applied concurrently at the primary – less chance for
contention

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

Performance Enhancements
SMP Support
• Takes advantage of SMP architecture and improves
scalability
• Parallelizing internal Replication Server processing
decreases latency and increases throughput
• Scales well for replication of multiple sources and
targets within the same server

Performance Enhancements
SMP Support
• Replication Server will utilize multiple processors on the
machine
• 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 run
concurrently
• Number of CPUs used by the server can be controlled by
binding the CPUs to the server using OS-specific
mechanisms
• e.g., psrset/pbind on Solaris
• Server can be forced into a single processor mode using
a switch
• configure replication server set smp_enable to {on | off}

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

Performance Enhancements
Commit Sequencing Enhancements
Internal Commit Sequencing
• Deadlock detection for transactions distributed across
Parallel DSI threads is now done internally in
Replication 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) – faster
commit processing
• Removes the reliance on replicate DB
• Eliminates a bottleneck (rs_threads) in the replicate DB
• Allows non-ASE environments to take advantage of the
Parallel 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 available
where needed