following functions map the contents of relational tables to XML values. They can be thought of as XML export functionality: table_to_xml ( table regclass, nulls boolean, tableforest boolean that transaction and the other does not. To solve this problem, PostgreSQL allows a transaction to export the snapshot it is using. As long as the exporting transaction remains open, other transactions can with the pg_export_snapshot function, shown in Table 9.90, and im- ported with the SET TRANSACTION command. Table 9.90. Snapshot Synchronization Functions Function Description pg_export_snapshot ()

following functions map the contents of relational tables to XML values. They can be thought of as XML export functionality: table_to_xml ( table regclass, nulls boolean, tableforest boolean that transaction and the other does not. To solve this problem, PostgreSQL allows a transaction to export the snapshot it is using. As long as the exporting transaction remains open, other transactions can pre-existing data, but act normally for changes they make themselves. Snapshots are exported with the pg_export_snapshot function, shown in Table 9.88, and im- ported with the SET TRANSACTION command. 373 Functions

following functions map the contents of relational tables to XML values. They can be thought of as XML export functionality: table_to_xml(tbl regclass, nulls boolean, tableforest boolean, targetns text) query_to_xml(query type (xid) is 32 bits wide and wraps around every 4 billion transactions. However, these functions export a 64-bit format that is extended with an “epoch” counter so it will not wrap around during the life that transaction and the other does not. To solve this problem, PostgreSQL allows a transaction to export the snapshot it is using. As long as the exporting transaction remains open, other transactions can

following functions map the contents of relational tables to XML values. They can be thought of as XML export functionality: table_to_xml(tbl regclass, nulls boolean, tableforest boolean, targetns text) query_to_xml(query type (xid) is 32 bits wide and wraps around every 4 billion transactions. However, these functions export a 64-bit format that is extended with an “epoch” counter so it will not wrap around during the life that transaction and the other does not. To solve this problem, PostgreSQL allows a transaction to export the snapshot it is using. As long as the exporting transaction remains open, other transactions can

following functions map the contents of relational tables to XML values. They can be thought of as XML export functionality: table_to_xml(tbl regclass, nulls boolean, tableforest boolean, targetns text) query_to_xml(query type (xid) is 32 bits wide and wraps around every 4 billion transactions. However, these functions export a 64-bit format that is extended with an “epoch” counter so it will not wrap around during the life that transaction and the other does not. To solve this problem, PostgreSQL allows a transaction to export the snapshot it is using. As long as the exporting transaction remains open, other transactions can

following functions map the contents of relational tables to XML values. They can be thought of as XML export functionality: table_to_xml ( table regclass, nulls boolean, tableforest boolean that transaction and the other does not. To solve this problem, PostgreSQL allows a transaction to export the snapshot it is using. As long as the exporting transaction remains open, other transactions can with the pg_export_snapshot function, shown in Table 9.90, and imported with the SET TRANSACTION command. Table 9.90. Snapshot Synchronization Functions Function Description pg_export_snapshot () →

following functions map the contents of relational tables to XML values. They can be thought of as XML export functionality: table_to_xml(tbl regclass, nulls boolean, tableforest boolean, targetns text) query_to_xml(query type (xid) is 32 bits wide and wraps around every 4 billion transactions. However, these functions export a 64-bit format that is extended with an “epoch” counter so it will not wrap around during the life that transaction and the other does not. To solve this problem, PostgreSQL allows a transaction to export the snapshot it is using. As long as the exporting transaction remains open, other transactions can

following functions map the contents of relational tables to XML values. They can be thought of as XML export functionality: table_to_xml ( table regclass, nulls boolean, 320 Functions and Operators that transaction and the other does not. To solve this problem, PostgreSQL allows a transaction to export the snapshot it is using. As long as the exporting transaction remains open, other transactions can existing data, but act normally for changes they make themselves. Snapshots are exported with the pg_export_snapshot function, shown in Table 9.88, and imported with the SET TRANSACTION command. 395 Functions

following functions map the contents of relational tables to XML values. They can be thought of as XML export functionality: table_to_xml(tbl regclass, nulls boolean, tableforest boolean, targetns text) query_to_xml(query type (xid) is 32 bits wide and wraps around every 4 billion transac- tions. However, these functions export a 64-bit format that is extended with an “epoch” counter so it will not wrap around during the life that transaction and the other does not. To solve this problem, PostgreSQL allows a transaction to export the snapshot it is using. As long as the exporting transaction remains open, other transactions can

following functions map the contents of relational tables to XML values. They can be thought of as XML export functionality: table_to_xml(tbl regclass, nulls boolean, tableforest boolean, targetns text) query_to_xml(query type (xid) is 32 bits wide and wraps around every 4 billion transactions. However, these functions export a 64-bit format that is extended with an “epoch” counter so it will not wrap around during the life that transaction and the other does not. To solve this problem, PostgreSQL allows a transaction to export the snapshot it is using. As long as the exporting transaction remains open, other transactions can