GoLang : Using sqlx for record mapping into Structs

Posted on Updated on

When working with GoLang and retrieving records from a database, this is typically done by retrieving a row and then parsing it to extract the various attributes and then in turn mapping them to variables to to a struct. For example, the following code shows the executing a query and then parsing the rows to process the returned attributes and assigning them to a variable.

import (
    "fmt"
    "time"
    "database/sql"
    godror "github.com/godror/godror"
)

func main(){
    username := <username>; 
    password := <password>;
    host := <host>:<port>;
    database := <database name>;

    <code to create the connection - didn't include to save space>

    dbQuery := "select table_name, tablespace_name from user_tables where table_name not like 'DM$%' and table_name not like 'ODMR$%'"
    rows, err := db.Query(dbQuery)
    if err != nil {
        fmt.Println(".....Error processing query")
        fmt.Println(err)
        return
    }
    defer rows.Close()

    fmt.Println("... Parsing query results") 
    var tableName string
    for rows.Next() {
        rows.Scan(&tableName)
        fmt.Println(tableName)
    }

   <code to close the connection - didn't include to save space>
}

As you can see this can add additional lines of code and corresponding debugging.

With the sqlx golang package, we can use their functionality to assign the query results to a struct. This simplifies the coding. The above code becomes the following:

import (
    "fmt"
    "time"
    "database/sql"
    godror "github.com/godror/godror"
    "github.com/jmoiron/sqlx"
)

type TableDetails struct {
    Table       string 'db:"TABLE_NAME"'
    Tablespace  string 'db:"TABLESPACE_NAME"'
}

func main(){
    username := <username>; 
    password := <password>;
    host := <host>:<port>;
    database := <database name>;

   <code to create the connection - didn't include to save space - this time connect using sqlx>

    // select all the rows and load into the struct, in one step
    dbQuery := "select table_name, tablespace_name from user_tables where table_name not like 'DM$%' and table_name not like 'ODMR$%'"
    table_rec := []TableDetails{}
    db.Select(&tanle_rec, dbQuery)

    // load each row separately
    table_rec := []TableDetails{}
    rows, err := db.Queryx(dbQuery)
    for rows.next() {
           // loads the current row into the struct
        err := rows.StructScan(&table_rec)
        fmt.Printf("%+v\n", table_rec)
    }

  <code to close the connection - didn't include to save space>
}

 

 

Adam Solver for Neural Networks (OML) in Oracle 21c

Posted on Updated on

Updated: Changed 20c to Oracle 21c, as Oracle 20c Database never really existed 🙂

The ability to create and use Neural Networks on business data has been available in Oracle Database since Oracle 18c (18c and 19c are just slightly extended versions of Oracle 12c). With each minor database release we get some small improvements and minor features added. I’ve written other blog posts about other 21c new machine learning features (see here, here and here).

With Oracle 21c they have added a new neural network solver. This is called Adam Solver and the original research was conducted by Diederik Kingma from OpenAI and Jimmy Ba from the University of Toronto and they presented they work at ICLR 2015. The name Adam is derived from ‘adaptive moment estimation‘. This algorithm, research and paper has gathered some attention in the research community over the past few years. Most of this has been focused on the benefits of using it.

Gentle Introduction to the Adam Optimization Algorithm for Deep ...

But care is needed. As with most machine learning (and deep learning) algorithms, they work up to a point. They may be good on certain problems and input data sets, and then for others they may not be as good or as efficient at producing an optimal outcome. Although using this solver may be beneficial to your problem, using the concept of ‘No Free Lunch’, you will need to prove the solver is beneficial for your problem.

With Oracle Machine Learning there are two Optimization Solver available for the Neural Network algorithm. The default solver is call L-BFGS (Limited memory Broyden-Fletch-Goldfarb-Shanno). This is one of the most popular solvers in use in most algorithms. The is a limited version of BFGS, using less memory (hence the L in the name) This solver finds the descent direction and line search is used to find the appropriate step size. The solver searches for the optimal solution of the loss function to find the extreme value (maximum or minimum) of the loss (cost) function

The Adam Solver uses an extension to stochastic gradient descent. It uses the squared gradients to scale the learning rate and it takes advantage of momentum by using moving average of the gradient instead of gradient. This allows the solver to work quickly by seeing less data and can work well with larger data sets.

With Oracle Data Mining the Adam Solver has the following parameters.

  • ADAM_ALPHA : Learning rate for solver. Default value is 0.001.
  • ADAM_BATCH_ROWS : Number of rows per batch. Default value is 10,000
  • ADAM_BETA1 : Exponential decay rate for 1st moment estimates. Default value is 0.9.
  • ADAM_BETA2 : Exponential decay rate for the 2nd moment estimates. Default value is 0.99.
  • ADAM_GRADIENT_TOLERANCE : Gradient infinity norm tolerance. Default value is 1E-9.

The parameters ADAM_ALPHA and ADAM_BATCH_ROWS can have an effect on the timing for the neural network algorithm to produce the model. Some exploration is needed to determine the optimal values for this parameters based on the size of the data set. For example having a larger value for ADAM_ALPHA results in a faster initial learning before the rates is updated. Small values than the default slows learning down during training.

To tell Oracle Machine Learning to use the Adam Solver the DMSSET_NN_SOLVER parameter needs to be set. The default setting for a neural network is DMSSET_NN_SOLVER_LGFGS.  But to use the Adam solver set it to DMSSET_NN_SOLVER_ADAM.

The following is an example of setting the parameters for the Adam solver and creating a neural network.

BEGIN
   DELETE FROM BANKING_NNET_SETTINGS;

   INSERT INTO BANKING_NNET_SETTINGS (setting_name, setting_value)
   VALUES (dbms_data_mining.algo_name, dbms_data_mining.algo_neural_network);

   INSERT INTO BANKING_NNET_SETTINGS (setting_name, setting_value)
   VALUES (dbms_data_mining.prep_auto, dbms_data_mining.prep_auto_on);

   INSERT INTO BANKING_NNET_SETTINGS (setting_name, setting_value)
   VALUES (dbms_data_mining.nnet_nodes_per_layer, '20,10,6');

   INSERT INTO BANKING_NNET_SETTINGS (setting_name, setting_value)
   VALUES (dbms_data_mining.nnet_iterations, 10);

   INSERT INTO BANKING_NNET_SETTINGS (setting_name, setting_value)
   VALUES (dbms_data_mining.NNET_SOLVER, 'NNET_SOLVER_ADAM');
END;

The addition of the last parameter overrides the default solver for building a neural network model.

To build the model we can use the following.

DECLARE
   v_start_time TIMESTAMP;
BEGIN
   begin DBMS_DATA_MINING.DROP_MODEL('BANKING_NNET_72K_1'); exception when others then null; end;

   v_start_time := current_timestamp;
   DBMS_DATA_MINING.CREATE_MODEL(
      model_name.         => 'BANKING_NNET_72K_1',
      mining_function     => dbms_data_mining.classification,
      data_table_name     => 'BANKING_72K',
      case_id_column_name => 'ID',
      target_column_name  => 'TARGET',
      settings_table_name => 'BANKING_NNET_SETTINGS');

   dbms_output.put_line('Time take to create model = ' || to_char(extract(second from (current_timestamp-v_start_time))) || ' seconds.');
END;

For me on my Oracle 20c Preview Database, this takes 1.8 seconds to run and create the neural network model ob a data set of 72,000 records.

Using the default solver, the model is created in 5.2 seconds. With using a small data set of 72,000 records, we can see the impact of using an Adam Solver  for creating a neural network model.

These timings and the timings shown below (in seconds) are based on the Oracle 20c Preview Database, using a minimum VM sizing and specification available.

Creating OML Models in Parallel

Posted on Updated on

In a previous post I showed how to use the partition option in Oracle Data Mining to create many sub-models. This gives one overall driving model with each sub-model created on a different subset or partition of the training data set.

That blog post also showed the timing for creating the models and how this compares to creating one overall model for your data set, while achieving greater accuracy with model predictions.

This is all good. But can it scale more. What if I have significantly more data!  How does this scale and how?

My previous blog post showed how the you can quickly partition the data into different subsets and some care is needed on choosing the attributes carefully for the partition key.

What if I want to run these different sub-models on the different data partitions in parallel on different slaves.

This is simple to do and can be achieved by adding one additional parameter to the Model Settings table. This parameter is called ODMS_PARTITION_BUILD_TYPE. This parameter has three possible values:

ODMS_PARTITION_BUILD_INTRA — Each partition is built in parallel using all slaves.

ODMS_PARTITION_BUILD_INTER — Each partition is built entirely in a single slave, but multiple partitions may be built at the same time since multiple slaves are active.

ODMS_PARTITION_BUILD_HYBRID — It is a combination of the other two types and is recommended for most situations to adapt to dynamic environments.

The default mode is ODMS_PARTITION_BUILD_HYBRID.

Although by default the model will try to run in parallel, I’ve found this is not necessarily the case. In my previous post I showed the timing to create a model on 72K records using different models. These timings are

One over all Model = 5.23 seconds

Partitioned Model (4 partitions/models) = 8.3 seconds

Partitioned Model (48 partitions/models) = 37 seconds

Now let’s change/set the ODMS_PARTITION_BUILD_TYPE parameter. The following code is the complete code to set the parameters and build upon those shown in the previous blog post.

BEGIN
    DELETE FROM BANKING_RF_SETTINGS;

    INSERT INTO banking_RF_settings (setting_name, setting_value)
    VALUES (dbms_data_mining.algo_name, dbms_data_mining.algo_random_forest);

    INSERT INTO banking_RF_settings (setting_name, setting_value)
    VALUES (dbms_data_mining.prep_auto, dbms_data_mining.prep_auto_on);

    INSERT INTO banking_RF_settings (setting_name, setting_value)
    VALUES (dbms_data_mining.odms_partition_columns, 'MARITAL, JOB’);

    INSERT INTO banking_RF_settings (setting_name, setting_value)
    VALUES (dbms_data_mining.odms_partition_build_type, 'ODMS_PARTITION_BUILD_INTER');

   COMMIT;
END;

The code to create the Model using CREATE_MODEL does not change.

So, how long this this take to run?  In my DBaaS preview 20c database (basic setup) it too 6.6 seconds.

Remember that was for an input data set consisting of 72K records and the partition key creates 48 partitions and in-turn creates 48 different machine learning models.

This 6.6 seconds compares to 37 seconds when this parameter was not set or using the default.

No that is fast and available to everyone to use 🙂

Partitioned Models – Oracle Machine Learning (OML)

Posted on Updated on

Building machine learning models can be a relatively trivial task. But getting to that point and understanding what to do next can be challenging. Yes the task of creating a model is simple and usually takes a few line of code. This is what is shown in most examples. But when you try to apply to real world problems we are faced with other challenges. Some of which include volume of data is larger, building efficient ML pipelines is challenging, time to create models gets longer, applying models to new data in real-time takes longer (not possible in real-time), etc. Yes these are typically challenges and most of these can be easily overcome.

When building ML solutions for real-world problem you will be faced with building (and deploying) many 10s or 100s of ML models. Why are so many models needed? Almost every example we see for ML takes the entire data set and build a model on that data. When you think about it, not everyone in the data set can be considered in the same grouping (similar characteristics). If we were to build a model on the data set and apply it to new data, we will get a generic prediction. A prediction comparing the new data item (new customer, purchase, etc) with everyone else in the data population. Maybe this is why so many ML project fail as they are building generic solution that performs badly when run on new (and evolving) data.

To overcome this we start to look at the different groups of data in the data set. Can the data set be divided into a number of different parts based on some characteristics. If we could do this and build a separate model on each group (or cluster), then we would have ML models that would be more accurate with their predictions. This is where we will end up creating 10s or 100s of models. As you can imagine the work involved in doing this with be LOTs. Then think about all the coding needed to manage all of this. What about the complexity of all the code needed for making the predictions on new data.

Yes all of this gets complex very, very quickly!
Ideally we want a separate model for each group

But how can you do that efficiently? is it possible?

When working with Oracle Machine Learning, you can use a feature called partitioned models. Partitioned Models are designed to handle this type of problem. They are designed to:

  • make the building of models simple
  • scales as the data and number of partitions increase
  • includes all the steps part of the ML pipeline (all the data prep, transformations, etc)
  • make predicting new data using the ML model simple
  • make the deployment of the ML model easy
  • make the MLOps process simple
  • make the use of ML model easy to use by all developers no matter the programming language
  • make the ML model build and ML model scoring quick and with better, more accurate predictions.

Screenshot 2020-06-15 11.11.42

Let us work through an example. In this example lets start by creating a Random Forest ML model using the entire data set. The following code shows setting up the Parameters settings table. The second code segment creates the Random Forest ML model. The training data set being used in this example contains 72,000 records.

BEGIN
  DELETE FROM BANKING_RF_SETTINGS;

  INSERT INTO banking_RF_settings (setting_name, setting_value)
  VALUES (dbms_data_mining.algo_name, dbms_data_mining.algo_random_forest);

  INSERT INTO banking_RF_settings (setting_name, setting_value)
  VALUES (dbms_data_mining.prep_auto, dbms_data_mining.prep_auto_on);

 COMMIT;
END;
/

-- Create the ML model
DECLARE
   v_start_time  TIMESTAMP;
BEGIN
   DBMS_DATA_MINING.DROP_MODEL('BANKING_RF_72K_1');

   v_start_time := current_timestamp;

   DBMS_DATA_MINING.CREATE_MODEL(
      model_name          => 'BANKING_RF_72K_1',
      mining_function     => dbms_data_mining.classification,
      data_table_name     => 'BANKING_72K',
      case_id_column_name => 'ID',
      target_column_name  => 'TARGET',
      settings_table_name => 'BANKING_RF_SETTINGS');

   dbms_output.put_line('Time take to create model = ' || to_char(extract(second from (current_timestamp-v_start_time))) || ' seconds.');
END;
/

This is the basic setup and the following table illustrates how long the CREATE_MODEL function takes to run for different sizes of training datasets and with different number of trees per model. The default number of trees is 20.

Screenshot 2020-06-15 12.19.51

To run this model against new data we could use something like the following SQL query.

SELECT cust_id, target,
       prediction(BANKING_RF_72K_1 USING *)  predicted_value,
       prediction_probability(BANKING_RF_72K_1 USING *) probability
FROM   bank_test_v;

This is simple and straight forward to use.

For the 72,000 records it takes just approx 5.23 seconds to create the model, which includes creating 20 Decision Trees. As mentioned earlier, this will be a generic model covering the entire data set.

To create a partitioned model, we can add new parameter which lists the attributes to use to partition the data set. For example, if the partition attribute is MARITAL, we see it has four different values. This means when this attribute is used as the partition attribute, Oracle Machine Learning will create four separate sub Random Forest models all until the one umbrella model. This means the above SQL query to run the model, does not change and the correct sub model will be selected to run on the data based on the value of MARITAL attribute.

To create this partitioned model you need to add the following to the settings table.

BEGIN
  DELETE FROM BANKING_RF_SETTINGS;

  INSERT INTO banking_RF_settings (setting_name, setting_value)
  VALUES (dbms_data_mining.algo_name, dbms_data_mining.algo_random_forest);

  INSERT INTO banking_RF_settings (setting_name, setting_value)
  VALUES (dbms_data_mining.prep_auto, dbms_data_mining.prep_auto_on);

  INSERT INTO banking_RF_settings (setting_name, setting_value)
  VALUES (dbms_data_mining.odms_partition_columns, 'MARITAL’);

COMMIT;
END;
/

The code to create the model remains the same!

The code to call and use the model remains the same!

This keeps everything very simple and very easy to use.

When I ran the CREATE_MODEL code for the partitioned model, it took approx 8.3 seconds to run. Yes it took slightly longer than the previous example, but this time it is creating four models instead of one. This is still very quick!

What if I wanted to add more attributes to the partition key? Yes you can do that. The more attributes you add, the more sub-models will be be created.

For example, if I was to add JOB attribute to the partition key list. I will now get 48 sub-models (with 20 Decision Trees each) being created. The JOB attribute has 12 distinct values, multiplied by the 4 values for MARITAL, gives us 48 models.

INSERT INTO banking_RF_settings (setting_name, setting_value)
VALUES (dbms_data_mining.odms_partition_columns, 'MARITAL,JOB');

How long does this take the CREATE_MODEL code to run? approx 37 seconds!

Again that is quick!

Again remember the code to create the model and to run the model to predict on new data does not change. This means our applications using this ML model does not change. This shows us we can very easily increase the predictive accuracy of our models with only adding one additional model, and by improving this accuracy by adding more attributes to the partition key.

But you do need to be careful with what attributes to include in the partition key. If the attributes have a very high number of distinct values, will result in 100s, or 1000s of sub models being created.

An important benefit of using partitioned models is when a new distinct value occurs in one of the partition key attributes. You code to create the parameters and models does not change. OML will automatically will pick this up and do all the work under the hood.

 

New Oracle Machine Learning Features in 19c and 20c

Posted on

Here are links to blog posts and articles I’ve written about the new features of Oracle Machine Learning in 19c (and previous) and 20c.

I’ve given a presentation on these topics at ACES@Home and Yatra online conferences.

Each of the following links will explain each of the algorithms, and gives demo code for you to try.

  • RandomForest

https://oralytics.com/2020/06/24/randomforest-machine-learning-oracle-machine-learning-oml/

  • Neural Networks

https://developer.oracle.com/databases/neural-network-machine-learning.html

  • Time Series Forecasting

https://oralytics.com/2019/04/15/time-series-forecasting-in-oracle-part-1/

https://oralytics.com/2019/04/23/time-series-forecasting-in-oracle-part-2/

  • XGBoost

https://oralytics.com/2020/04/27/xgboost-in-oracle-20c/

  • Multivariate State Estimation Technique (MSET)

https://oralytics.com/2020/04/13/mset-multivariate-state-estimation-technique-in-oracle-20c/

  • Partitioned Models

https://oralytics.com/2020/07/13/partitioned-models-oracle-machine-learning-oml/

  • Parallel Model Creation

https://oralytics.com/2020/07/27/creating-oml-models-in-parallel/

 

GoLang: Links to blog posts – working with Oracle Database

Posted on Updated on

This post is to serve as a link to my other blog posts on using GoLang and connecting to/working with data from an Oracle Database.

 

Connecting Go Lang to Oracle Database

The database driver/library got renamed. The following post goes through how to updated to new name.

GoLang: Oracle driver/library renamed to : godror

GoLang: Querying records from Oracle Database using goracle

GoLang: Inserting records into Oracle Database using goracle

Importance of setting Fetched Rows size for Database Query using Golang

GoLang – Consuming Oracle REST API from an Oracle Cloud Database)

Machine Learning with Go Lang

 

This post will be updated with new GoLang posts.

 

 

RandomForest Machine Learning – Oracle Machine Learning (OML)

Posted on

Oracle Machine Learning has 30+ different machine learning algorithms built into the database. This means you can use SQL to create machine learning models and then use these models to score or label new data stored in the database or as the data is being created dynamically in the applications.

One of the most commonly used machine learning algorithms, over the past few years, is can RandomForest. This post will take a closer look at this algorithm and how you can build & use a RandomForest model.

Random Forest is known as an ensemble machine learning technique that involves the creation of hundreds of decision tree models. These hundreds of models are used to label or score new data by evaluating each of the decision trees and then determining the outcome based on the majority result from all the decision trees. Just like in the game show. The combining of a number of different ways of making a decision can result in a more accurate result or prediction.

Random Forest models can be used for classification and regression types of problems, which form the majority of machine learning systems and solutions. For classification problems, this is where the target variable has either a binary value or a small number of defined values. For classification problems the Random Forest model will evaluate the predicted value for each of the decision trees in the model. The final predicted outcome will be the majority vote for all the decision trees. For regression problems the predicted value is numeric and on some range or scale. For example, we might want to predict a customer’s lifetime value (LTV), or the potential value of an insurance claim, etc. With Random Forest, each decision tree will make a prediction of this numeric value. The algorithm will then average these values for the final predicted outcome.

 

Under the hood, Random Forest is a collection of decision trees. Although decision trees are a popular algorithm for machine learning, they can have a tendency to over fit the model. This can lead higher than expected errors when predicting unseen data. It also gives just one possible way of representing the data and being able to derive a possible predicted outcome.

Random Forest on the other hand relies of the predicted outcomes from many different decision trees, each of which is built in a slightly different way. It is an ensemble technique that combines the predicted outcomes from each decision tree to give one answer. Typically, the number of trees created by the Random Forest algorithm is defined by a parameter setting, and in most languages this can default to 100+ or 200+ trees.

The Random Forest algorithm has three main features:

  • It uses a method called bagging to create different subsets of the original training data
  • It will randomly section different subsets of the features/attributes and build the decision tree based on this subset
  • By creating many different decision trees, based on different subsets of the training data and different subsets of the features, it will increase the probability of capturing all possible ways of modeling the data

For each decision tree produced, the algorithm will use a measure, such as the Gini Index, to select the attributes to split on at each node of the decision tree.

To create a RandomForest model using Oracle Data Mining, you will follow the same process as with any of the other algorithms, the core of these are:

  1. define the parameter settings
  2. create the model
  3. score/label new data

Let’s start with the first step, defining the parameters. As with all the classification algorithms the same or similar parameters are set. With RandomForest we can set an additional parameter which tells the algorithm how many decision trees to create as part of the model. By default, 20 decision trees will be created. But if you want to change this number you can use the RFOR_NUM_TREES parameter. Remember the larger the value the longer it will take to create the model. But will have better accuracy. On the other hand with a small number of trees the quicker the model build will be, but might night be as accurate. This is something you will need to explore and determine. In the following example I change the number of trees to created to ten.

CREATE TABLE BANKING_RF_SETTINGS (
    SETTING_NAME VARCHAR2(50),
    SETTING_VALUE VARCHAR2(50)
);

BEGIN
  DELETE FROM BANKING_RF_SETTINGS;

  INSERT INTO banking_RF_settings (setting_name, setting_value)
  VALUES (dbms_data_mining.algo_name, dbms_data_mining.algo_random_forest);

  INSERT INTO banking_RF_settings (setting_name, setting_value)
  VALUES (dbms_data_mining.prep_auto, dbms_data_mining.prep_auto_on);

  INSERT INTO banking_RF_settings (setting_name, setting_value)
  VALUES (dbms_data_mining.RFOR_NUM_TREES, 10);

  COMMIT;
END;

Other default parameters used include, for creating each decision tree, use random 50% selection of columns and 50% sample of training data.

Now for step 2, create the model.

DECLARE
   v_start_time  TIMESTAMP;
BEGIN
   DBMS_DATA_MINING.DROP_MODEL('BANKING_RF_72K_1');

   v_start_time := current_timestamp;

   DBMS_DATA_MINING.CREATE_MODEL(
      model_name          => 'BANKING_RF_72K_1',
      mining_function     => dbms_data_mining.classification,
      data_table_name     => 'BANKING_72K',
      case_id_column_name => 'ID',
      target_column_name  => 'TARGET',
      settings_table_name => 'BANKING_RF_SETTINGS');

   dbms_output.put_line('Time take to create model = ' || to_char(extract(second from (current_timestamp-v_start_time))) || ' seconds.');
END;

The above code measures how long it takes to create the model.

I’ve run this same parameters and create models for different training data set sizes. I’ve also changed the number of decision trees to create. The following table shows the timings.

You can see it took 5.23 seconds to create a RandomForest model using the default settings for a data set of 72K records. This increase to just over one minute for a data set of 2 million records. Yo can also see the effect of reducing the number of decision trees on how long it takes the create model to run.

For step 3, on using the model on new data, this is just the same as with any of the classification models. Here is an example:

SELECT cust_id, target,
       prediction(BANKING_RF_72K_1 USING *)  predicted_value,
       prediction_probability(BANKING_RF_72K_1 USING *) probability
FROM   bank_test_v;

 

That’s it. That’s all there is to creating a RandomForest machine learning model using Oracle Machine Learning.

It’s quick and easy 🙂

 

GoLang: Oracle driver/library renamed to : godror

Posted on Updated on

I’ve posted some previously about using Golang with Oracle. Connecting to an Oracle Database and processing the data.

Golang is very very fast and efficient at processing this data. Much faster than a very commonly used language.

But my previous blog posts on using Golang, have used a driver/library called  goracle.  Here is the link to the blog post on setting it up and connecting to an Oracle Database.

A few months ago goracle was deprecated because of naming (trademark) issues.

But it has been renamed to godror.

The problem now is I need to go an update all the code I’ve written and change all the environment variables to reflect the new driver.

Thankfully the developer of this driver has posted the following code on Github to do this work for you. But you may still encounter some things that require manual changes. If you have only a few Golang programmes, then go ahead and do it manually.

 

You can use "sed" to change everything:

sed -i -e 's,goracle "gopkg.in/goracle.v2",godror "github.com/godror/godror",g; s,gopkg.in/goracle.v2,github.com/godror/godror,g; s/"goracle"/"godror"/g; s/goracle[.]/godror./g' $(find . -type f -name '*.go')
sed -i -e '/goracle.v2/d' go.mod

To change everything using modules:

for dn in $(fgrep -l goracle.v2 $(find . -type f -name 'go.mod') | sed -e 's,/go.mod$,,'); do 
  (cd "$dn" && git pull && sed -i -e 's,goracle "gopkg.in/goracle.v2",godror "github.com/godror/godror",g; s,gopkg.in/goracle.v2,github.com/godror/godror,g; s/"goracle"/"godror"/g; s/goracle[.]/godror./g' $(find . -type f -name '*.go') && sed -i -e '/goracle.v2/d' go.mod  && git commit -am 'goracle -> godror' && git push)
done

GoLang – Consuming Oracle REST API from an Oracle Cloud Database)

Posted on Updated on

Does anyone write code to access data in a database anymore, and by code I mean SQL?  The answer to this question is ‘It Depends’, just like everything in IT.

Using REST APIs is very common for accessing processing data with a Database. From using an API to retrieve data, to using a slightly different API to insert data, and using other typical REST functions to perform your typical CRUD operations. Using REST APIs allows developers to focus on write efficient applications in a particular application, instead of having to swap between their programming language and SQL. In later cases most developers are not expert SQL developer or know how to work efficiently with the data. Therefore leave the SQL and procedural coding to those who are good at that, and then expose the data and their code via REST APIs. The end result is efficient SQL and Database coding, and efficient application coding. This is a win-win for everyone.

I’ve written before about creating REST APIs in an Oracle Cloud Database (DBaaS and Autonomous). In these writings I’ve shown how to use the in-database machine learning features and to use REST APIs to create an interface to the Machine Learning models. These models can be used to to score new data, making a machine learning prediction. The data being used for the prediction doesn’t have to exist in the database, instead the database is being used as a machine learning scoring engine, accessed using a REST API.

Check out an article I wrote about this and creating a REST API for an in-database machine learning model, for Oracle Magazine.

In that article I showed how easy it was to use the in-database machine model using Python.

Python has a huge fan and user base, but some of the challenges with Python is with performance, as it is an interrupted language. Don’t get be wrong on this, as lots of work has gone into making Python more efficient. But in some scenarios it just isn’t fast enough. In does scenarios people will switch into using other quicker to execute languages such as C, C++, Java and GoLang.

Here is the GoLang code to call the in-database machine learning model and process the returned data.

import (
    "bytes"
    "encoding/json"
    "fmt"
    "io/ioutil"
    "net/http"
    "os"
)

func main() {
    fmt.Println("---------------------------------------------------")
    fmt.Println("Starting Demo - Calling Oracle in-database ML Model")
    fmt.Println("")

    // Define variables for REST API and parameter for first prediction
    rest_api = "<full REST API>"

    // This wine is Bad
    a_country := "Portugal"
    a_province := "Douro"
    a_variety := "Portuguese Red"
    a_price := "30"

    // call the REST API adding in the parameters
    response, err := http.Get(rest_api +"/"+ a_country +"/"+ a_province +"/"+ a_variety +"/"+ a_price)
    if err != nil {
        // an error has occurred. Exit
        fmt.Printf("The HTTP request failed with error :: %s\n", err)
        os.Exit(1)
    } else {
        // we got data! Now extract it and print to screen
        responseData, _ := ioutil.ReadAll(response.Body)
        fmt.Println(string(responseData))
    }
    response.Body.Close()

    // Lets do call it again with a different set of parameters

    // This wine is Good - same details except the price is different
    a_price := "31"

    // call the REST API adding in the parameters
    response, err := http.Get(rest_api +"/"+ a_country +"/"+ a_province +"/"+ a_variety +"/"+ a_price)
    if err != nil {
        // an error has occurred. Exit
        fmt.Printf("The HTTP request failed with error :: %s\n", err)
        os.Exit(1)
    } else {
        responseData, _ := ioutil.ReadAll(response.Body)
        fmt.Println(string(responseData))
    }
    defer response.Body.Close()

    // All done! 
    fmt.Println("")
    fmt.Println("...Finished Demo ...")
    fmt.Println("---------------------------------------------------")
}

 

XGBoost in Oracle 20c

Posted on Updated on

Updated: Changed 20c to Oracle 21c, as Oracle 20c Database never really existed 🙂

Another of the new machine learning algorithms in Oracle 21c Database is called XGBoost. Most people will have come across this algorithm due to its recent popularity with winners of Kaggle competitions and other similar events.

XGBoost is an open source software library providing a gradient boosting framework in most of the commonly used data science, machine learning and software development languages. It has it’s origins back in 2014, but the first official academic publication on the algorithm was published in 2016 by Tianqi Chen and Carlos Guestrin, from the University of Washington.

The algorithm builds upon the previous work on Decision Trees, Bagging, Random Forest, Boosting and Gradient Boosting. The benefits of using these various approaches are well know, researched, developed and proven over many years. XGBoost can be used for the typical use cases of Classification including classification, regression and ranking problems. Check out the original research paper for more details of the inner workings of the algorithm.

Regular machine learning models, like Decision Trees, simply train a single model using a training data set, and only this model is used for predictions. Although a Decision Tree is very simple to create (and very very quick to do so) its predictive power may not be as good as most other algorithms, despite providing model explainability. To overcome this limitation ensemble approaches can be used to create multiple Decision Trees and combines these for predictive purposes. Bagging is an approach where the predictions from multiple DT models are combined using majority voting. Building upon the bagging approach Random Forest uses different subsets of features and subsets of the training data, combining these in different ways to create a collection of DT models and presented as one model to the user. Boosting takes a more iterative approach to refining the models by building sequential models with each subsequent model is focused on minimizing the errors of the previous model. Gradient Boosting uses gradient descent algorithm to minimize errors in subsequent models. Finally with XGBoost builds upon these previous steps enabling parallel processing, tree pruning, missing data treatment, regularization and better cache, memory and hardware optimization. It’s commonly referred to as gradient boosting on steroids.

The following three images illustrates the differences between Decision Trees, Random Forest and XGBoost.

The XGBoost algorithm in Oracle 20c has over 40 different parameter settings, and with most scenarios the default settings with be fine for most scenarios. Only after creating a baseline model with the details will you look to explore making changes to these. Some of the typical settings include:

  • Booster =  gbtree
  • #rounds for boosting = 10
  • max_depth = 6
  • num_parallel_tree = 1
  • eval_metric = Classification error rate  or  RMSE for regression

 

As with most of the Oracle in-database machine learning algorithms, the setup and defining the parameters is really simple. Here is an example of minimum of parameter settings that needs to be defined.

BEGIN
   -- delete previous setttings
   DELETE FROM banking_xgb_settings;

   INSERT INTO BANKING_XGB_SETTINGS (setting_name, setting_value)
   VALUES (dbms_data_mining.algo_name, dbms_data_mining.algo_xgboost);

   -- For 0/1 target, choose binary:logistic as the objective.
   INSERT INTO BANKING_XGB_SETTINGS (setting_name, setting_value)
   VALUES (dbms_data_mining.xgboost_objective, 'binary:logistic);

   commit;
END;

 

To create an XGBoost model run the following.


BEGIN
   DBMS_DATA_MINING.CREATE_MODEL (
      model_name          => 'BANKING_XGB_MODEL',
      mining_function     => dbms_data_mining.classification,
      data_table_name     => 'BANKING_72K',
      case_id_column_name => 'ID',
      target_column_name  => 'TARGET',
      settings_table_name => 'BANKING_XGB_SETTINGS');
END;

That’s all nice and simple, as it should be, and the new model can be called in the same manner as any of the other in-database machine learning models using functions like PREDICTION, PREDICTION_PROBABILITY, etc.

One of the interesting things I found when experimenting with XGBoost was the time it took to create the completed model. Using the default settings the following table gives the time taken, in seconds to create the model.

As you can see it is VERY quick even for large data sets and gives greater predictive accuracy.

 

MSET (Multivariate State Estimation Technique) in Oracle 20c

Posted on Updated on

Updated: Changed 20c to Oracle 21c, as Oracle 20c Database never really existed 🙂

Oracle 21c Database comes with some new in-database Machine Learning algorithms.

The short name for one of these is called MSET or Multivariate State Estimation Technique. That’s the simple short name. The more complete name is Multivariate State Estimation Technique – Sequential Probability Ratio Test.  That is a long name, and the reason is it consists of two algorithms. The first part looks at creating a model of the training data, and the second part looks at how new data is statistical different to the training data.

 

What are the use cases for this algorithm?  This algorithm can be used for anomaly detection.

Anomaly Detection, using algorithms, is able identifying unexpected items or events in data that differ to the norm. It can be easy to perform some simple calculations and graphics to examine and present data to see if there are any patterns in the data set. When the data sets grow it is difficult for humans to identify anomalies and we need the help of algorithms.

The images shown here are easy to analyze to spot the anomalies and it can be relatively easy to build some automated processing to identify these. Most of these solutions can be considered AI (Artificial Intelligence) solutions as they mimic human behaviors to identify the anomalies, and these example don’t need deep learning, neural networks or anything like that.

Other types of anomalies can be easily spotted in charts or graphics, such as the chart below.

There are many different algorithms available for anomaly detection, and the Oracle Database already has an algorithm called the One-Class Support Vector Machine. This is a variant of the main Support Vector Machine (SVD) algorithm, which maps or transforms the data, using a Kernel function, into space such that the data belonging to the class values are transformed by different amounts. This creates a Hyperplane between the mapped/transformed values and hopefully gives a large margin between the mapped/transformed points. This is what makes SVD very accurate, although it does have some scaling limitations. For a One-Class SVD, a similar process is followed. The aim is for anomalous data to be mapped differently to common or non-anomalous data, as shown in the following diagram.

 

Getting back to the MSET algorithm. Remember it is a 2-part algorithm abbreviated to MSET. The first part is a non-linear, nonparametric anomaly detection algorithm that calibrates the expected behavior of a system based on historical data from the normal sequence of monitored signals. Using data in time series format (DATE, Value) the training data set contains data consisting of “normal” behavior of the data. The algorithm creates a model to represent this “normal”/stationary data/behavior. The second part of the algorithm compares new or live data and calculates the differences between the estimated and actual signal values (residuals). It uses Sequential Probability Ratio Test (SPRT) calculations to determine whether any of the signals have become degraded. As you can imagine the creation of the training data set is vital and may consist of many iterations before determining the optimal training data set to use.

MSET has its origins in computer hardware failures monitoring. Sun Microsystems have been were using it back in the late 1990’s-early 2000’s to monitor and detect for component failures in their servers. Since then MSET has been widely used in power generation plants, airplanes, space travel, Disney uses it for equipment failures, and in more recent times has been extensively used in IOT environments with the anomaly detection focused on signal anomalies.

How does MSET work in Oracle 21c?

An important point to note before we start is, you can use MSET on your typical business data and other data stored in the database. It isn’t just for sensor, IOT, etc data mentioned above and can be used in many different business scenarios.

The first step you need to do is to create the time series data. This can be easily done using a view, but a Very important component is the Time attribute needs to be a DATE format. Additional attributes can be numeric data and these will be used as input to the algorithm for model creation.

-- Create training data set for MSET
CREATE OR REPLACE VIEW mset_train_data
AS SELECT time_id, 
          sum(quantity_sold) quantity,
          sum(amount_sold) amount 
FROM (SELECT * FROM sh.sales WHERE time_id <= '30-DEC-99’)
GROUP BY time_id 
ORDER BY time_id;

The example code above uses the SH schema data, and aggregates the data based on the TIME_ID attribute. This attribute is a DATE data type. The second import part of preparing and formatting the data is Ordering of the data. The ORDER BY is necessary to ensure the data is fed into or processed by the algorithm in the correct time series order.

The next step involves defining the parameters/hyper-parameters for the algorithm. All algorithms come with a set of default values, and in most cases these are suffice for your needs. In that case, you only need to define the Algorithm Name and to turn on Automatic Data Preparation. The following example illustrates this and also includes examples of setting some of the typical parameters for the algorithm.

BEGIN
  DELETE FROM mset_settings;

  -- Select MSET-SPRT as the algorithm
  INSERT  INTO mset_sh_settings (setting_name, setting_value)
  VALUES(dbms_data_mining.algo_name, dbms_data_mining.algo_mset_sprt);

  -- Turn on automatic data preparation
  INSERT INTO mset_sh_settings (setting_name, setting_value)
  VALUES(dbms_data_mining.prep_auto, dbms_data_mining.prep_auto_on);

  -- Set alert count
  INSERT INTO mset_sh_settings (setting_name, setting_value)
  VALUES(dbms_data_mining.MSET_ALERT_COUNT, 3);

  -- Set alert window
  INSERT INTO mset_sh_settings (setting_name, setting_value)
  VALUES(dbms_data_mining.MSET_ALERT_WINDOW, 5);

  -- Set alpha
  INSERT INTO mset_sh_settings (setting_name, setting_value)
  VALUES(dbms_data_mining.MSET_ALPHA_PROB, 0.1);

  COMMIT;
END;

To create the MSET model using the MST_TRAIN_DATA view created above, we can run:

BEGIN
--   DBMS_DATA_MINING.DROP_MODEL(MSET_MODEL');

   DBMS_DATA_MINING.CREATE_MODEL (
      model_name          => 'MSET_MODEL',
      mining_function     => dbms_data_mining.classification,
      data_table_name     => 'MSET_TRAIN_DATA',
      case_id_column_name => 'TIME_ID',
      target_column_name  => '',
      settings_table_name => 'MSET_SETTINGS');
END;

The SELECT statement below is an example of how to call and run the MSET model to label the data to find anomalies. The PREDICTION function will return a values of 0 (zero) or 1 (one) to indicate the predicted values. If the predicted values is 0 (zero) the MSET model has predicted the input record to be anomalous, where as a predicted values of 1 (one) indicates the value is typical. This can be used to filter out the records/data you will want to investigate in more detail.

-- display all dates with Anomalies
SELECT time_id, pred
FROM (SELECT time_id, prediction(mset_sh_model using *) over (ORDER BY time_id) pred 
      FROM mset_test_data)
WHERE pred = 0;

Benchmarking calling Oracle Machine Learning using REST

Posted on Updated on

Over the past year I’ve been presenting, blogging and sharing my experiences of using REST to expose Oracle Machine Learning models to developers in other languages, for example Python.

One of the questions I’ve been asked is, Does it scale?

Although I’ve used it in several projects to great success, there are no figures I can report publicly on how many REST API calls can be serviced 😦

But this can be easily done, and the results below are based on using and Oracle Autonomous Data Warehouse (ADW) on the Oracle Always Free.

The machine learning model is built on a Wine reviews data set, using Oracle Machine Learning Notebook as my tool to write some SQL and PL/SQL to build out a model to predict Good or Bad wines, based on the Prices and other characteristics of the wine. A REST API was built using this model to allow for a developer to pass in wine descriptors and returns two values to indicate if it would be a Good or Bad wine and the probability of this prediction.

No data is stored in the database. I only use the machine learning model to make the prediction

I built out the REST API using APEX, and here is a screenshot of the GET API setup.

Here is an example of some Python code to call the machine learning model to make a prediction.

import json
import requests

country = 'Portugal'
province = 'Douro'
variety = 'Portuguese Red'
price = '30'

resp = requests.get('https://jggnlb6iptk8gum-adw2.adb.us-ashburn-1.oraclecloudapps.com/ords/oml_user/wine/wine_pred/'+country+'/'+province+'/'+'variety'+'/'+price)
json_data = resp.json()
print (json.dumps(json_data, indent=2))

—–

{
  "pred_wine": "LT_90_POINTS",
  "prob_wine": 0.6844716987704507
}

But does this scale, as in how many concurrent users and REST API calls can it handle at the same time.

To test this I multi-threaded processes in Python to call a Python function to call the API, while ensuring a range of values are used for the input parameters. Some additional information for my tests.

  • Each function call included two REST API calls
  • Test effect of creating X processes, at same time
  • Test effect of creating X processes in batches of Y agents
  • Then, the above, with function having one REST API call and also having two REST API calls, to compare timings
  • Test in range of parallel process from 10 to 1,000 (generating up to 2,000 REST API calls at a time)

Some of the results. The table shows the time(*) in seconds to complete the number of processes grouped into batches (agents). My laptop was the limiting factor in these tests. It wasn’t able to test when the number of parallel processes when above 500. That is why I broke them into batches consisting of X agents

* this is the total time to run all the Python code, including the time taken to create each process.

Some observations:

  • Time taken to complete each function/process was between 0.45 seconds and 1.65 seconds, for two API calls.
  • When only one API call, time to complete each function/process was between 0.32 seconds and 1.21 seconds
  • Average time for each function/process was 0.64 seconds for one API functions/processes, and 0.86 for two API calls in function/process
  • Table above illustrates the overhead associated with setting up, calling, and managing these processes

As you can see, even with the limitations of my laptop, using an Oracle Database, in-database machine learning and REST can be used to create a Micro-Service type machine learning scoring engine. Based on these numbers, this machine learning micro-service would be able to handle and process a large number of machine learning scoring in Real-Time, and these numbers would be well within the maximum number of such calls in most applications. I’m sure I could process more parallel processes if I deployed on a different machine to my laptop and maybe used a number of different machines at the same time

How many applications within you enterprise needs to process move than 6,000 real-time machine learning scoring per minute?  This shows us the Oracle Always Free offering is capable and suitable for most applications.

Now, if you are processing more than those numbers per minutes then perhaps you need to move onto the paid options.

What next? I’ll spin up two VMs on Oracle Always Free, install Python, copy code into these VMs and have then run in parallel 🙂