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Questions - b-tree

Associating an index with a query in MongoDB?

If there are multiple indexes for a given collection, what determines which index is used when a query is submitted? Can the query submitter select which index to use? If so, how?
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Bear Bile Farming is Torture

mongodb

indexing

backend

b-tree

Votes: 0

Answers: 1

Latest Answer

MongoDB uses a query planner to automatically select an index. You can view the options considered for a query with the explain command. Use hint to force the index to use.
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Joe

B+ Trees internal nodes

I was working through a textbook and got stuck on this question: "Consider a B+ Tree where each leaf block can contain a maximum of 3 records, each internal block can contain a maximum of 3 keys,...
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jielouis341

data-structures

tree

binary-tree

abstract-syntax-tree

b-tree

Votes: 0

Answers: 1

Latest Answer

You have already done the right thing for the leaf level. There is only one internal block needed, which will have 4 pointers to those leaf blocks, and 3 keys. Those 3 keys are keys that typically are...
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trincot

How to create a subrange of a BTreeSet<(String, String, String)>? How to turn a tuple of bounds into a bound of a tuple?

I am trying to use a BTreeSet<(String, String, String)> as a way to create a simple in-memory 'triple store'. To be precise: type Entity = String; type Attribute = String; type Value = String; t...
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Qqwy

rust

tuples

range

multi-index

b-tree

Votes: 0

Answers: 2

Latest Answer

Since Borrow always returns a reference (grrrrrrrr), and Borrowed isn't necessarily Copy, you might be able to rely on a sentinel memory address? Note that since associated static items aren't allowed...
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Solomon Ucko

How to apply the index line &quot;my_table_&lt;custom_name&gt;&quot; btree (&lt;comma, separated, fields&gt;) to a table?

I am managing a postgres db created by third parts. One of the tables is described as \d my_table; Table "my_table" ... Indexes: "my_table_pkey" PRIMARY KEY, btree (dt, ida...
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Tms91

database

postgresql

indexing

b-tree

b-tree-index

Votes: 0

Answers: 1

Latest Answer

The two last lines indicate indexes, which were created after the table was created, with the following commands: CREATE INDEX my_table_fa ON my_table(dt, idd, idt, idfa, fnc); CREATE INDEX my_table_...
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Tms91

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