Picture Perfect 4.6 Enterprise Edition User Manual - UTCFS Global ...

Picture Perfect 4.6 Enterprise Edition User Manual - UTCFS Global ... Picture Perfect 4.6 Enterprise Edition User Manual - UTCFS Global ...

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98Picture Perfect 4.6 Enterprise EditionUser ManualReplication conceptsThis section includes the following FAQs:1 What is the difference between the ‘old’ refreshers and Enterprise Replication (ER)?2 Previously, changes to global replicated tables and inserts/deletes of person/badge were allowedfrom the nethost only. Is this still true?3 How are id conflicts handled when inserts are allowed from all hosts?4 Can we use max(id) to get the next id value when inserting to replicated tables?5 Are changes from a subhost propagated to other subhosts even when the nethost is not up?6 Are all tables replicated?7 Is native Informix replication used for all the tables?8 Does ER need the modify date/time information to be maintained?9 How are conflicts handled when changes are made on two hosts at the same time?10 What happens if the same table record (same primary key value) is updated from two hosts atthe same time (same timestamp)?1 What is the difference between the ‘old’ refreshers and Enterprise Replication (ER)?• The refreshers used in previous Picture Perfect versions synchronized between nethost andsubhost sequentially. Any synchronization delay with a single subhost affected all subhosts.With Informix ER in Picture Perfect 4.6, synchronization is done in parallel and is not affectedby latency to one or more hosts.• The refreshers are considerably slower than the native Informix ER.2 Previously, changes to global replicated tables and inserts/deletes of person/badge wereallowed from the nethost only. Is this still true?• Department, Personnel Type, BID format, Category, Facility, Permission Group, Time Zone,Custom List, and Custom Form records can be inserted/updated/deleted from all hosts.• Person and Badge records can be inserted and deleted from all hosts.3 How are id conflicts handled when inserts are allowed from all hosts?Each host is allocated a set of id values (sequences). The sequence ranges are as follows:• Nethost: 1 to 134 million• Subhost 1: 134 million + 1 to 268 million. . . . . .• Subhost 31: 134 million + 31 to 268 millionEach host uses a sequence value when assigning a value to an id field in replicated tables. Thesesequences need to be used during insertion to replicated tables. The stored proceduregetnextseqval('table_name') ensures the appropriate sequence and its maintenance per

Chapter 7FAQs99host. The client user interfaces and the import software provided with Picture Perfect use this storedprocedure. We recommend that all third parties also use this stored procedure.Note:Category inserts are allowed at subhosts only when the nethost database is up. The reason for this exception isthat only 64K categories are supported. Instead of partitioning the 64K between 31 subhosts, a design decisionwas made to keep track of the category count on the nethost and use a sequence object to control the creation.4 Can we use max(id) to get the next id value when inserting to replicated tables?No, the client user interfaces and the import software provided with Picture Perfect use sequences.We recommend that any third party software used to insert data to these tables also use thegetnextseqval() stored procedure. If max(id) is used, an error (SQL error -746) is returned.5 Are changes from a subhost propagated to other subhosts even when the nethost is notup?No, the nethost database needs to be up for the changes from a subhost to be propagated to othersubhosts.6 Are all tables replicated?Not all tables are replicated. Only person-related and global tables are replicated. The replicatedtables are:• person• badge• person_user• person_category• temp_category• notes (for person/badge only)• category• facility• person_type• department• permission_group• host_bid_format• custom_form• custom_list_elem• site_lists• form_tab• custom_control• custom_control_arg• time_zone• time_zone_dst

98<strong>Picture</strong> <strong>Perfect</strong> <strong>4.6</strong> <strong>Enterprise</strong> <strong>Edition</strong><strong>User</strong> <strong>Manual</strong>Replication conceptsThis section includes the following FAQs:1 What is the difference between the ‘old’ refreshers and <strong>Enterprise</strong> Replication (ER)?2 Previously, changes to global replicated tables and inserts/deletes of person/badge were allowedfrom the nethost only. Is this still true?3 How are id conflicts handled when inserts are allowed from all hosts?4 Can we use max(id) to get the next id value when inserting to replicated tables?5 Are changes from a subhost propagated to other subhosts even when the nethost is not up?6 Are all tables replicated?7 Is native Informix replication used for all the tables?8 Does ER need the modify date/time information to be maintained?9 How are conflicts handled when changes are made on two hosts at the same time?10 What happens if the same table record (same primary key value) is updated from two hosts atthe same time (same timestamp)?1 What is the difference between the ‘old’ refreshers and <strong>Enterprise</strong> Replication (ER)?• The refreshers used in previous <strong>Picture</strong> <strong>Perfect</strong> versions synchronized between nethost andsubhost sequentially. Any synchronization delay with a single subhost affected all subhosts.With Informix ER in <strong>Picture</strong> <strong>Perfect</strong> <strong>4.6</strong>, synchronization is done in parallel and is not affectedby latency to one or more hosts.• The refreshers are considerably slower than the native Informix ER.2 Previously, changes to global replicated tables and inserts/deletes of person/badge wereallowed from the nethost only. Is this still true?• Department, Personnel Type, BID format, Category, Facility, Permission Group, Time Zone,Custom List, and Custom Form records can be inserted/updated/deleted from all hosts.• Person and Badge records can be inserted and deleted from all hosts.3 How are id conflicts handled when inserts are allowed from all hosts?Each host is allocated a set of id values (sequences). The sequence ranges are as follows:• Nethost: 1 to 134 million• Subhost 1: 134 million + 1 to 268 million. . . . . .• Subhost 31: 134 million + 31 to 268 millionEach host uses a sequence value when assigning a value to an id field in replicated tables. Thesesequences need to be used during insertion to replicated tables. The stored proceduregetnextseqval('table_name') ensures the appropriate sequence and its maintenance per

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