READ_TREE

Reads the contents of trees within the random forest or XGBoost model.

Reads the contents of trees within the random forest or XGBoost model.

Syntax

READ_TREE ( USING PARAMETERS model_name = 'model-name' [, tree_id = tree-id] [, format = 'format'] )

Parameters

model_name
Identifies the model that is stored as a result of training, where model-name conforms to conventions described in Identifiers. It must also be unique among all names of sequences, tables, projections, views, and models within the same schema.
tree_id
The tree identifier, an integer between 0 and n-1, where n is the number of trees in the random forest or XGBoost model. If you omit this parameter, all trees are returned.
format
Output format of the returned tree, one of the following:

  • tabular: Returns a table with the twelve output columns.

  • graphviz: Returns DOT language source that can be passed to a graphviz tool and render a graphic visualization of the tree.

Privileges

Non-superusers: USAGE privileges on the model

Examples

Get tabular output from READ_TREE for a random forest model:

=> SELECT READ_TREE ( USING PARAMETERS model_name='myRFModel', tree_id=1 ,
format= 'tabular') LIMIT 2;
-[ RECORD 1 ]-------------+-------------------
tree_id                   | 1
node_id                   | 1
node_depth                | 0
is_leaf                   | f
is_categorical_split      | f
split_predictor           | petal_length
split_value               | 1.921875
weighted_information_gain | 0.111242236024845
left_child_id             | 2
right_child_id            | 3
prediction                |
probability/variance      |

-[ RECORD 2 ]-------------+-------------------
tree_id                   | 1
node_id                   | 2
node_depth                | 1
is_leaf                   | t
is_categorical_split      |
split_predictor           |
split_value               |
weighted_information_gain |
left_child_id             |
right_child_id            |
prediction                | setosa
probability/variance      | 1

Get graphviz-formatted output from READ_TREE:

=> SELECT READ_TREE ( USING PARAMETERS model_name='myRFModel', tree_id=1 ,
format= 'graphviz')LIMIT 1;

-[ RECORD 1 ]+-------------------------------------------------------------------
---------------------------------------------------------------------------------
tree_id      | 1
tree_digraph | digraph Tree{
1 [label="petal_length < 1.921875 ?", color="blue"];
1 -> 2 [label="yes", color="black"];
1 -> 3 [label="no", color="black"];
2 [label="prediction: setosa, probability: 1", color="red"];
3 [label="petal_length < 4.871875 ?", color="blue"];
3 -> 6 [label="yes", color="black"];
3 -> 7 [label="no", color="black"];
6 [label="prediction: versicolor, probability: 1", color="red"];
7 [label="prediction: virginica, probability: 1", color="red"];
}

This renders as follows:

See also