index_object:max() | Tarantool

index_object:max()

object index_object
index_object:max([key])

Find the maximum value in the specified index.

Parameters:
Return:

the tuple for the last key in the index. If the optional key value is supplied, returns the last key that is less than or equal to key. Starting with Tarantool 2.0.4, index_object:max(key) returns nothing if key doesn’t match any value in the index.

Rtype:

tuple

Possible errors:

  • Index is not of type ‘TREE’.
  • ER_TRANSACTION_CONFLICT if a transaction conflict is detected in the MVCC transaction mode.

Complexity factors: index size, index type.

Example:

Below are few examples of using max. To try out these examples, you need to bootstrap a Tarantool database as described in Using data operations.

-- Insert test data --
box.space.bands:insert { 1, 'Roxette', 1986 }
box.space.bands:insert { 2, 'Scorpions', 1965 }
box.space.bands:insert { 3, 'Ace of Base', 1987 }
box.space.bands:insert { 4, 'The Beatles', 1960 }
box.space.bands:insert { 5, 'Pink Floyd', 1965 }
box.space.bands:insert { 6, 'The Rolling Stones', 1962 }
box.space.bands:insert { 7, 'The Doors', 1965 }
box.space.bands:insert { 8, 'Nirvana', 1987 }
box.space.bands:insert { 9, 'Led Zeppelin', 1968 }
box.space.bands:insert { 10, 'Queen', 1970 }

-- Find the maximum value in the specified index
max = box.space.bands.index.year:max()
--[[
---
- [8, 'Nirvana', 1987]
...
--]]

-- Find the maximum value that matches the partial key value
max_partial = box.space.bands.index.year_band:max(1965)
--[[
---
- [7, 'The Doors', 1965]
...
--]]
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