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https://issues.apache.org/jira/browse/MADLIB-1460?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17266484#comment-17266484
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Frank McQuillan commented on MADLIB-1460:
-----------------------------------------
(2)
Run with 5 billion rows (which is > 2^32):
Train
{code}
DROP TABLE IF EXISTS tab1;
CREATE TABLE tab1(
indep_var BIGINT,
dep_var BIGINT
);
INSERT INTO tab1 VALUES(generate_series(1,5000000000),
generate_series(1,5000000000));
DROP TABLE IF EXISTS test_linregr, test_linregr_summary;
SELECT madlib.linregr_train( 'tab1',
'test_linregr',
'dep_var',
'ARRAY[1, indep_var]'
);
linregr_train
---------------
(1 row)
Time: 375514.851 ms
{code}
Predict
{code}
test=# create table tab_pred_out as select madlib.linregr_predict(coef,
ARRAY[1, indep_var]
) as predict from tab1,test_linregr;
SELECT 5000000000
{code}
Note need to run as CTAS query. otherwise it fails with the error PGresult
cannot support more than INT_MAX tuples. This is because before printing to the
console, postgres tries to store the result of the query in a PGresult object
which does not support bigint
{code}
test=# select madlib.linregr_predict(coef,
ARRAY[1, indep_var]
) from tab1,test_linregr;
PGresult cannot support more than INT_MAX tuples
{code}
> Prevent an "integer out of range" exception in linear regression train
> ----------------------------------------------------------------------
>
> Key: MADLIB-1460
> URL: https://issues.apache.org/jira/browse/MADLIB-1460
> Project: Apache MADlib
> Issue Type: Improvement
> Components: Module: Linear Regression
> Reporter: Daniel Daniel
> Priority: Minor
> Fix For: v1.18.0
>
>
> Linear regression training results in 2 output tables (*neither are
> optional*):
> * The *primary* output table, that includes the computed coefficients.
> * A *summary* output table, that contains a single line.
> +Scenario+
> Running the linear regression training in postgresql on an input table which
> has *more than 2^31 records* within it (even if a grouping column is
> specified), fails due to an "*integer out of range*" exception.
> +Source+
> *The summary table* has a column that stores *the total number of records*
> involved in the computation. The column's data type is a *singed integer*.
> However, the total number of records is computed as a *BIGINT*. Therefore,
> when the total number of records in the input table is beyond the range of a
> signed integer (i.e., 2^31), an "integer out of range" exception is thrown.
> +Solution+
> A simple solution is to change the data type of the column from a *signed
> integer* into a *BIGINT*.
> +Test+
> We have executed the linear regression training function with and without the
> suggested modification on an input table having between 2^31-2^32 records.
> Without the modification, an integer out of range exception was thrown. After
> modifying the code as suggested, it worked perfectly.
>
>
>
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