Algorithms for merged indexes
records, e.g., records representing or indexing rows in a materialized view that summarize the total value of each order by summing up order details, can be concurrency bottlenecks and might therefore warrant special lock types. Escrow locks [O 86] can be employed and can be augmented with intent-to-escrow lock modes for use in upper B-tree levels [GZ 04]. Traditional shared and exclusive locks can be combined with escrow locks within the same B-tree, such that rows from tables and materialized and indexed views can be co-located in the same merged index and each locked appropriately for its use. A typical example is a merged index with an index from the table orders and an index on a view that summarizes order details for each order.
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