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When many keys are deleted from an index, causing many nodes to become empty, searching for a key value can require walking over many of these empty nodes. This can slow performance. In particular, we noticed that the space management index of a variable-length data file experienced this issue. A simple case that demonstrates this issue is to add records to a variable-length data file, then delete all or many of the records, and add more records. The second set of adds takes longer than the first due to the presence of the empty nodes in the index tree.
The default NODE_DELAY settings for FairCom RTG have been changed from 75 to 0. A NODE_DELAY value of 0 causes the delete node thread to wait 1 second before pruning a node from the index tree.
