# Performance

Rules that flag suboptimal code.
Table of Contents

## AvoidDebugStatements

Since: PMD 6.36.0

Priority: Medium (3)

Debug statements contribute to longer transactions and consume Apex CPU time even when debug logs are not being captured.

When possible make use of other debugging techniques such as the Apex Replay Debugger and Checkpoints that could cover most use cases.

For other valid use cases that the statement is in fact valid make use of the `@SuppressWarnings` annotation or the `//NOPMD` comment.

This rule is defined by the following XPath expression:

    //MethodCallExpression[lower-case(@FullMethodName)='system.debug']

Example(s):

    public class Foo {
        public void bar() {
            Account acc = [SELECT Name, Owner.Name FROM Account LIMIT 1];
            System.debug(accs); // will get reported
        }

        @SuppressWarnings('PMD.AvoidDebugStatements')
        public void baz() {
            try {
                Account myAccount = bar();
            } catch (Exception e) {
                System.debug(LoggingLevel.ERROR, e.getMessage()); // good to go
            }
        }
    }

Use this rule by referencing it:

    <rule ref="category/apex/performance.xml/AvoidDebugStatements" />

## AvoidNonRestrictiveQueries

Since: PMD 7.4.0

Priority: Medium (3)

When working with very large amounts of data, unfiltered SOQL or SOSL queries can quickly cause governor limit exceptions.

This rule is defined by the following Java class: net.sourceforge.pmd.lang.apex.rule.performance.AvoidNonRestrictiveQueriesRule

Example(s):

    public class Something {
        public static void main( String[] as ) {
            Account[] accs1 = [ select id from account ];  // Bad
            Account[] accs2 = [ select id from account limit 10 ];  // better

            List<List<SObject>> searchList = [FIND 'map*' IN ALL FIELDS RETURNING Account (Id, Name), Contact, Opportunity, Lead]; // bad
        }
    }

Use this rule by referencing it:

    <rule ref="category/apex/performance.xml/AvoidNonRestrictiveQueries" />

## EagerlyLoadedDescribeSObjectResult

Since: PMD 6.40.0

Priority: Medium (3)

This rule finds `DescribeSObjectResult`s which could have been loaded eagerly via `SObjectType.getDescribe()`.

When using `SObjectType.getDescribe()` or `Schema.describeSObjects()` without supplying a `SObjectDescribeOptions`, implicitly it will be using `SObjectDescribeOptions.DEFAULT` and then all child relationships will be loaded eagerly regardless whether this information is needed or not. This has a potential negative performance impact. Instead `SObjectType.getDescribe(options)` or `Schema.describeSObjects(SObjectTypes, options)` should be used and a `SObjectDescribeOptions` should be supplied. By using `SObjectDescribeOptions.DEFERRED` the describe attributes will be lazily initialized at first use.

Lazy loading `DescribeSObjectResult` on picklist fields is not always recommended. The lazy loaded describe objects might not be 100% accurate. It might be safer to explicitly use `SObjectDescribeOptions.FULL` in such a case. The same applies when you need the same `DescribeSObjectResult` to be consistent across different contexts and API versions.

Properties:

- `noDefault`: The behavior of `SObjectDescribeOptions.DEFAULT` changes from API Version 43 to 44: With API Version 43, the attributes are loaded eagerly. With API Version 44, they are loaded lazily. Simply using `SObjectDescribeOptions.DEFAULT` doesn’t automatically make use of lazy loading. (unless “Use Improved Schema Caching” critical update is applied, `SObjectDescribeOptions.DEFAULT` does fallback to lazy loading) With this property enabled, such usages are found. You might ignore this, if you can make sure, that you don’t run a mix of API Versions.

This rule is defined by the following XPath expression:

    //MethodCallExpression
        [
            lower-case(@MethodName) = "getdescribe" and ReferenceExpression[@SObjectType = true()]
            or lower-case(@MethodName) = "describesobjects"
        ]
        [not(VariableExpression/ReferenceExpression
                [lower-case(@Image) = ("sobjectdescribeoptions", "fielddescribeoptions")]
             )
        ]
    |
    //ReferenceExpression
        [$noDefault = true()]
        [lower-case(@Image) = "sobjectdescribeoptions"]
        [parent::VariableExpression[lower-case(@Image) = "default"]]

Example(s):

    public class Foo {
        public static void bar(List<Account> accounts) {
            if (Account.SObjectType.getDescribe(SObjectDescribeOptions.DEFERRED).isCreateable()) {
                insert accounts;
            }
        }
    }

This rule has the following properties:

Name | Default Value | Description
--- | --- | ---
noDefault | false | Do not allow SObjectDescribeOptions.DEFAULT option to ensure consistent results no matter where getDescribe is called

Use this rule with the default properties by just referencing it:

    <rule ref="category/apex/performance.xml/EagerlyLoadedDescribeSObjectResult" />

Use this rule and customize it:

    <rule ref="category/apex/performance.xml/EagerlyLoadedDescribeSObjectResult">
        <properties>
            <property name="noDefault" value="false" />
        </properties>
    </rule>

## OperationWithHighCostInLoop

Since: PMD 7.0.0

Priority: Medium (3)

This rule finds method calls inside loops that are known to be likely a performance issue. These methods should be called only once before the loop.

Schema class methods like Schema.getGlobalDescribe() and Schema.describeSObjects() might be slow depending on the size of your organization. Calling these methods repeatedly inside a loop creates a potential performance issue.

This rule is defined by the following Java class: net.sourceforge.pmd.lang.apex.rule.performance.OperationWithHighCostInLoopRule

Example(s):

    public class GlobalDescribeExample {
        // incorrect example
        public void getGlobalDescribeInLoop() {
            Set<String> fieldNameSet = new Set<String> {'Id'};
            for (String fieldNameOrDefaultValue : fieldNameOrDefaultValueList) {
                // Schema.getGlobalDescribe() should be called only once before the for-loop
                if (Schema.getGlobalDescribe().get(objectName).getDescribe().fields.getMap().containsKey(fieldNameOrDefaultValue.trim())) {
                    fieldNameSet.add(fieldNameOrDefaultValue);
                }
            }
        }

        // corrected example
        public void getGlobalDescribeInLoopCorrected() {
            Map<String, Schema.SObjectField> fieldMap = Schema.getGlobalDescribe().get(objectName).getDescribe().fields.getMap();
            Set<String> fieldNameSet = new Set<String> {'Id'};
            for (String fieldNameOrDefaultValue : fieldNameOrDefaultValueList) {
                if (fieldMap.containsKey(fieldNameOrDefaultValue.trim())) {
                    fieldNameSet.add(fieldNameOrDefaultValue);
                }
            }
        }
    }

    public class DescribeSObjectsExample {
        // incorrect example
        public void describeSObjectsInLoop() {
            Set<String> fieldNameSet = new Set<String> {'Id'};
            for (String fieldNameOrDefaultValue : fieldNameOrDefaultValueList) {
                Schema.DescribeSObjectResult dsr = Account.sObjectType.getDescribe();
                if (Schema.describeSObjects(new List<String> { sObjectType })[0].fields.getMap().containsKey(fieldNameOrDefaultValue.trim())) {
                    fieldNameSet.add(fieldNameOrDefaultValue);
                }
            }
        }

        // corrected example
        public void describeSObjectsInLoop() {
            Map<String, Schema.SObjectField> fieldMap = Schema.describeSObjects(new List<String> { 'Account' })[0].fields.getMap();
            Set<String> fieldNameSet = new Set<String> {'Id'};
            for (String fieldNameOrDefaultValue : fieldNameOrDefaultValueList) {
                if (fieldMap.containsKey(fieldNameOrDefaultValue.trim())) {
                    fieldNameSet.add(fieldNameOrDefaultValue);
                }
            }
        }
    }

Use this rule by referencing it:

    <rule ref="category/apex/performance.xml/OperationWithHighCostInLoop" />

## OperationWithLimitsInLoop

Since: PMD 6.29.0

Priority: Medium (3)

Database class methods, DML operations, SOQL queries, SOSL queries, Approval class methods, Email sending, async scheduling or queueing within loops can cause governor limit exceptions. Instead, try to batch up the data into a list and invoke the operation once on that list of data outside the loop.

This rule is defined by the following Java class: net.sourceforge.pmd.lang.apex.rule.performance.OperationWithLimitsInLoopRule

Example(s):

    public class Something {
        public void databaseMethodInsideOfLoop(List<Account> accounts) {
            for (Account a : accounts) {
                Database.insert(a);
            }
        }

        public void dmlInsideOfLoop() {
            for (Integer i = 0; i < 151; i++) {
                Account account;
                // ...
                insert account;
            }
        }

        public void soqlInsideOfLoop() {
            for (Integer i = 0; i < 10; i++) {
                List<Account> accounts = [SELECT Id FROM Account];
            }
        }

        public void soslInsideOfLoop() {
            for (Integer i = 0; i < 10; i++) {
                List<List<SObject>> searchList = [FIND 'map*' IN ALL FIELDS RETURNING Account (Id, Name), Contact, Opportunity, Lead];
            }
        }

        public void messageInsideOfLoop() {
            for (Integer i = 0; i < 10; i++) {
                Messaging.SingleEmailMessage email = new Messaging.SingleEmailMessage();
                Messaging.sendEmail(new Messaging.SingleEmailMessage[]{email});
            }
        }

        public void approvalInsideOfLoop(Account[] accs) {
            for (Integer i = 0; i < 10; i++) {
                Account acc = accs[i];
                Approval.ProcessSubmitRequest req = new Approval.ProcessSubmitRequest();
                req.setObjectId(acc.Id);
                Approval.process(req);
                Approval.lock(acc);
                Approval.unlock(acc);
            }
        }

        public void asyncInsideOfLoop() {
            for (Integer i = 0; i < 10; i++) {
                System.enqueueJob(new MyQueueable());
                System.schedule('x', '0 0 0 1 1 ?', new MySchedule());
                System.scheduleBatch(new MyBatch(), 'x', 1);
            }
        }
    }

Use this rule by referencing it:

    <rule ref="category/apex/performance.xml/OperationWithLimitsInLoop" />