Associating getMore commands with the original query

[csarrazi]

Currently, when running mloginfo --queries, all getmore commands are grouped by collection, even though they may not be associated to the same query. Finding the query associated with a getmore command can be achieved by comparing the cursor ID. This way, instead of grouping all getmore commands in a single line, they could actually be grouped by query signature. This would very much improve the output of mloginfo --queries, and provide a much better understanding of the reasons why getmore commands can be slow, at times.

It is important to note that there are a few cases where we cannot associate a getmore with a specific query:

• if the log file was rotated in the middle of a cursor iteration (the query and getmore commands would then be in different log files)
• if the initial query takes less time than the actual getmore commands (this is possible if there are yields when returning the documents with the getmore command).