Add comprehensive GlideRecord performance optimization techniques

Core ServiceNow APIs/GlideRecord/Performance Optimization Techniques/README.md

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+# GlideRecord Performance Optimization Techniques
+
+This collection provides advanced techniques for optimizing GlideRecord queries and database operations in ServiceNow.
+
+## Overview
+
+Performance optimization is crucial for maintaining responsive ServiceNow applications, especially when dealing with large datasets or complex queries. These snippets demonstrate best practices for efficient GlideRecord usage.
+
+## Key Performance Principles
+
+- **Minimize Database Roundtrips**: Use efficient query patterns
+- **Proper Indexing**: Leverage indexed fields in queries
+- **Batch Operations**: Process multiple records efficiently
+- **Query Optimization**: Use appropriate query methods
+- **Memory Management**: Handle large datasets responsibly
+
+## Snippets Included
+
+1. **optimized_batch_processing.js** - Efficient batch processing techniques
+2. **indexed_field_queries.js** - Leveraging database indexes
+3. **chunked_data_processing.js** - Processing large datasets in chunks
+4. **query_performance_comparison.js** - Performance comparison examples
+5. **memory_efficient_operations.js** - Memory-conscious GlideRecord usage
+
+## Performance Monitoring
+
+Always measure performance using:
+- `gs.log()` with timestamps for execution time
+- Database query metrics in Developer Tools
+- Performance Analytics for production monitoring
+
+## Best Practices Summary
+
+1. Always query on indexed fields when possible
+2. Use `setLimit()` for large result sets
+3. Avoid using `getRowCount()` on large tables
+4. Use `chooseWindow()` for pagination
+5. Consider using `GlideAggregate` for statistical queries
+6. Implement proper error handling and logging
+
+## Related Documentation
+
+- [ServiceNow GlideRecord API Documentation](https://developer.servicenow.com/dev.do#!/reference/api/tokyo/server/no-namespace/c_GlideRecordScopedAPI)
+- [Query Performance Best Practices](https://docs.servicenow.com/bundle/tokyo-platform-administration/page/administer/managing-data/concept/query-performance.html)

Core ServiceNow APIs/GlideRecord/Performance Optimization Techniques/indexed_field_queries.js

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+/**
+ * Indexed Field Query Optimization
+ * 
+ * This snippet demonstrates how to leverage database indexes for optimal query performance
+ * in ServiceNow GlideRecord operations.
+ * 
+ * Use Case: High-performance queries on large tables
+ * Performance Benefits: Faster query execution, reduced database load
+ * 
+ * @author ServiceNow Community
+ * @version 1.0
+ */
+
+// Method 1: Using Indexed Fields for Optimal Performance
+function queryWithIndexedFields() {
+    var gr = new GlideRecord('incident');
+
+    // GOOD: Query on indexed fields (state, priority, assignment_group are typically indexed)
+    gr.addQuery('state', 'IN', '2,3'); // Work in Progress, On Hold
+    gr.addQuery('priority', '<=', '3'); // High priority and above
+    gr.addQuery('assignment_group', '!=', ''); // Has assignment group
+
+    // GOOD: Use sys_created_on for date ranges (indexed timestamp)
+    gr.addQuery('sys_created_on', '>=', gs.daysAgoStart(7));
+    gr.addQuery('sys_created_on', '<=', gs.daysAgoEnd(1));
+
+    // GOOD: Order by indexed field
+    gr.orderBy('sys_created_on');
+
+    gr.query();
+
+    var results = [];
+    while (gr.next()) {
+        results.push({
+            number: gr.getDisplayValue('number'),
+            state: gr.getDisplayValue('state'),
+            priority: gr.getDisplayValue('priority')
+        });
+    }
+
+    return results;
+}
+
+// Method 2: Avoiding Non-Indexed Field Queries
+function avoidNonIndexedQueries() {
+    // BAD EXAMPLE - Don't do this on large tables
+    function badQueryExample() {
+        var gr = new GlideRecord('incident');
+
+        // BAD: Contains query on non-indexed text field
+        gr.addQuery('description', 'CONTAINS', 'network issue');
+
+        // BAD: Complex wildcard search
+        gr.addQuery('short_description', 'STARTSWITH', 'Unable');
+
+        gr.query();
+        return gr.getRowCount(); // Also bad on large tables
+    }
+
+    // GOOD ALTERNATIVE - Use indexed fields and full-text search
+    function goodQueryAlternative() {
+        var gr = new GlideRecord('incident');
+
+        // GOOD: Use category/subcategory (often indexed)
+        gr.addQuery('category', 'network');
+
+        // GOOD: Use indexed fields first to narrow results
+        gr.addQuery('state', 'IN', '1,2,3');
+        gr.addQuery('sys_created_on', '>=', gs.daysAgoStart(30));
+
+        // Then filter on text if needed (smaller result set)
+        gr.addQuery('short_description', 'CONTAINS', 'unable');
+
+        gr.query();
+
+        var results = [];
+        while (gr.next()) {
+            results.push(gr.getUniqueValue());
+        }
+
+        return results;
+    }
+
+    return goodQueryAlternative();
+}
+
+// Method 3: Compound Index Optimization
+function optimizeCompoundIndexes() {
+    var gr = new GlideRecord('task');
+
+    // GOOD: Query fields in order that matches compound indexes
+    // Many tables have compound indexes on (table, state, assigned_to)
+    gr.addQuery('state', '!=', '7'); // Not closed
+    gr.addQuery('assigned_to', '!=', ''); // Has assignee
+
+    // Add additional filters after indexed ones
+    gr.addQuery('priority', '<=', '3');
+
+    // Order by indexed field for better performance
+    gr.orderBy('sys_updated_on');
+
+    gr.query();
+
+    return gr.getRowCount();
+}
+
+// Method 4: Reference Field Optimization
+function optimizeReferenceQueries() {
+    // GOOD: Query reference fields by sys_id (indexed)
+    function queryByReferenceId() {
+        var groupSysId = getAssignmentGroupSysId('Hardware');
+
+        var gr = new GlideRecord('incident');
+        gr.addQuery('assignment_group', groupSysId); // Uses index
+        gr.addQuery('state', '!=', '7'); // Not closed
+        gr.query();
+
+        return gr.getRowCount();
+    }
+
+    // LESS OPTIMAL: Query by reference field display value
+    function queryByDisplayValue() {
+        var gr = new GlideRecord('incident');
+        gr.addQuery('assignment_group.name', 'Hardware'); // Less efficient
+        gr.addQuery('state', '!=', '7');
+        gr.query();
+
+        return gr.getRowCount();
+    }
+
+    // BEST: Combine both approaches
+    function optimizedReferenceQuery() {
+        // First get the sys_id using indexed query
+        var groupGR = new GlideRecord('sys_user_group');
+        groupGR.addQuery('name', 'Hardware');
+        groupGR.query();
+
+        if (groupGR.next()) {
+            var groupSysId = groupGR.getUniqueValue();
+
+            // Then use sys_id in main query (indexed)
+            var gr = new GlideRecord('incident');
+            gr.addQuery('assignment_group', groupSysId);
+            gr.addQuery('state', '!=', '7');
+            gr.query();
+
+            return gr.getRowCount();
+        }
+
+        return 0;
+    }
+
+    return optimizedReferenceQuery();
+}
+
+// Method 5: Date Range Optimization
+function optimizeDateRangeQueries() {
+    // GOOD: Use built-in date functions with indexed timestamps
+    function efficientDateQuery() {
+        var gr = new GlideRecord('incident');
+
+        // Use sys_created_on (indexed) with built-in functions
+        gr.addQuery('sys_created_on', '>=', gs.daysAgoStart(30));
+        gr.addQuery('sys_created_on', '<=', gs.daysAgoEnd(1));
+
+        // Add other indexed filters
+        gr.addQuery('state', '!=', '7');
+
+        gr.query();
+        return gr.getRowCount();
+    }
+
+    // LESS OPTIMAL: Complex date calculations
+    function lessOptimalDateQuery() {
+        var gr = new GlideRecord('incident');
+
+        // Complex date calculation (harder to optimize)
+        var thirtyDaysAgo = new GlideDateTime();
+        thirtyDaysAgo.addDaysUTC(-30);
+
+        gr.addQuery('sys_created_on', '>=', thirtyDaysAgo);
+        gr.query();
+
+        return gr.getRowCount();
+    }
+
+    return efficientDateQuery();
+}
+
+// Method 6: Query Performance Analysis
+function analyzeQueryPerformance() {
+    var queries = [
+        {
+            name: 'Indexed Query',
+            query: function() {
+                var gr = new GlideRecord('incident');
+                gr.addQuery('state', '2');
+                gr.addQuery('priority', '1');
+                gr.setLimit(100);
+                gr.query();
+                return gr.getRowCount();
+            }
+        },
+        {
+            name: 'Non-Indexed Query',
+            query: function() {
+                var gr = new GlideRecord('incident');
+                gr.addQuery('description', 'CONTAINS', 'test');
+                gr.setLimit(100);
+                gr.query();
+                return gr.getRowCount();
+            }
+        }
+    ];
+
+    queries.forEach(function(queryTest) {
+        var startTime = new Date().getTime();
+        var result = queryTest.query();
+        var endTime = new Date().getTime();
+        var executionTime = endTime - startTime;
+
+        gs.log(queryTest.name + ':');
+        gs.log('  Execution time: ' + executionTime + 'ms');
+        gs.log('  Result count: ' + result);
+        gs.log('  Performance rating: ' + (executionTime < 100 ? 'Good' : executionTime < 500 ? 'Fair' : 'Poor'));
+    });
+}
+
+// Helper function
+function getAssignmentGroupSysId(groupName) {
+    var gr = new GlideRecord('sys_user_group');
+    gr.addQuery('name', groupName);
+    gr.query();
+
+    if (gr.next()) {
+        return gr.getUniqueValue();
+    }
+
+    return '';
+}
+
+// Method 7: Index-Aware Pagination
+function indexAwarePagination(pageSize, pageNumber) {
+    pageSize = pageSize || 50;
+    pageNumber = pageNumber || 0;
+
+    var gr = new GlideRecord('incident');
+
+    // Use indexed fields for filtering
+    gr.addQuery('state', 'IN', '1,2,3');
+    gr.addQuery('sys_created_on', '>=', gs.daysAgoStart(90));
+
+    // Order by indexed field for consistent pagination
+    gr.orderBy('sys_created_on');
+    gr.orderByDesc('sys_id'); // Secondary sort for tie-breaking
+
+    // Use chooseWindow for efficient pagination
+    gr.chooseWindow(pageNumber * pageSize, (pageNumber + 1) * pageSize);
+
+    gr.query();
+
+    var results = [];
+    while (gr.next()) {
+        results.push({
+            sys_id: gr.getUniqueValue(),
+            number: gr.getDisplayValue('number'),
+            short_description: gr.getDisplayValue('short_description'),
+            state: gr.getDisplayValue('state')
+        });
+    }
+
+    return {
+        data: results,
+        page: pageNumber,
+        pageSize: pageSize,
+        hasMore: results.length === pageSize
+    };
+}