Implement total count optimization when first page query returns less than pagesize amount of data

CHANGELOG.md

@@ -3,6 +3,11 @@ All notable changes to this project will be documented in this file.
 
 The format is based on [Keep a Changelog](http://keepachangelog.com/) and this project adheres to [Semantic Versioning](http://semver.org/).
 
+## [1.2.0] - 2026-03-20
+
+Optimization:
+- Skip querying the database for the total count when the count can be determined from the number of elements returned from the first page.
+
 ## [1.1.1] - 2026-01-02
 
 Fixes:

Directory.Build.props

@@ -7,7 +7,7 @@
         <PackageProjectUrl>https://github.com/Jameak/CursorPagination</PackageProjectUrl>
         <PackageTags>cursor paginate pagination keyset offset skip source generator queryable</PackageTags>
         <PackageDescription>An easy-to-use efficient KeySet- and Offset-pagination implementation for IQueryable with included opaque Cursor support.</PackageDescription>
-        <VersionPrefix>1.1.1</VersionPrefix>
+        <VersionPrefix>1.2.0</VersionPrefix>
         <VersionSuffix></VersionSuffix>
         <PackageVersion Condition="'$(VersionSuffix)' == ''">$(VersionPrefix)</PackageVersion>
         <PackageVersion Condition="'$(VersionSuffix)' != ''">$(VersionPrefix)-$(VersionSuffix)</PackageVersion>

samples/Jameak.CursorPagination.Sample/Controllers/PaginatedDataController.cs

@@ -6,6 +6,7 @@
 using Microsoft.AspNetCore.Mvc;
 
 namespace Jameak.CursorPagination.Sample.Controllers;
+
 [ApiController]
 [Route("api/[controller]/[action]")]
 public class PaginatedDataController : ControllerBase

src/Jameak.CursorPagination.SourceGenerator/DiagnosticHelper.cs

@@ -5,6 +5,7 @@
 #pragma warning disable RS2008 // Analyzer release tracking
 
 namespace Jameak.CursorPagination.SourceGenerator;
+
 internal static class DiagnosticHelper
 {
     private const string UsageCategory = "Usage";

src/Jameak.CursorPagination.SourceGenerator/ExtensionMethods.cs

@@ -5,6 +5,7 @@
 using Microsoft.CodeAnalysis.Operations;
 
 namespace Jameak.CursorPagination.SourceGenerator;
+
 internal static class ExtensionMethods
 {
     private static readonly SymbolDisplayFormat s_fullyQualifiedWithNullRefModifier =

src/Jameak.CursorPagination.SourceGenerator/Extractors/BaseExtractor.PaginationPropertyExtractionHelper.cs

@@ -7,6 +7,7 @@
 using static Jameak.CursorPagination.SourceGenerator.HelperMethods;
 
 namespace Jameak.CursorPagination.SourceGenerator.Extractors;
+
 internal abstract partial class BaseExtractor
 {
     private sealed class PaginationPropertyExtractionHelper

src/Jameak.CursorPagination.SourceGenerator/Extractors/BaseExtractor.cs

@@ -3,6 +3,7 @@
 using static Jameak.CursorPagination.SourceGenerator.HelperMethods;
 
 namespace Jameak.CursorPagination.SourceGenerator.Extractors;
+
 internal abstract partial class BaseExtractor
 {
     internal abstract bool TryHandle(GeneratorAttributeSyntaxContext context, INamedTypeSymbol generatorClassSymbol, out BaseExtractedData? extractedData);

src/Jameak.CursorPagination.SourceGenerator/Extractors/KeySetExtractor.cs

@@ -5,6 +5,7 @@
 using static Jameak.CursorPagination.SourceGenerator.HelperMethods;
 
 namespace Jameak.CursorPagination.SourceGenerator.Extractors;
+
 internal sealed class KeySetExtractor : BaseExtractor
 {
     internal override bool TryHandle(GeneratorAttributeSyntaxContext context, INamedTypeSymbol generatorClassSymbol, out BaseExtractedData? extractedData)

src/Jameak.CursorPagination.SourceGenerator/Extractors/OffsetExtractor.cs

@@ -4,6 +4,7 @@
 using static Jameak.CursorPagination.SourceGenerator.HelperMethods;
 
 namespace Jameak.CursorPagination.SourceGenerator.Extractors;
+
 internal sealed class OffsetExtractor : BaseExtractor
 {
     internal override bool TryHandle(GeneratorAttributeSyntaxContext context, INamedTypeSymbol generatorClassSymbol, out BaseExtractedData? extractedData)

src/Jameak.CursorPagination.SourceGenerator/HelperMethods.cs

@@ -10,6 +10,7 @@
 using Microsoft.CodeAnalysis.CSharp.Syntax;
 
 namespace Jameak.CursorPagination.SourceGenerator;
+
 internal static class HelperMethods
 {
 

src/Jameak.CursorPagination.SourceGenerator/KeySetPaginationClassBuilder.cs

@@ -9,6 +9,7 @@
 using static Jameak.CursorPagination.SourceGenerator.HelperMethods;
 
 namespace Jameak.CursorPagination.SourceGenerator;
+
 internal static class KeySetPaginationClassBuilder
 {
     private const string PrivateHelperClassName = "PrivateHelper";
@@ -411,8 +412,8 @@
             };
 
             return orEqual
                 ? (isGreaterThan ? ">=" : "<=")
                 : (isGreaterThan ? ">" : "<");
         }
 
         static string CreateComparisonString(PropertyConfiguration property, string operation)

src/Jameak.CursorPagination.SourceGenerator/OffsetPaginationClassBuilder.cs

@@ -6,6 +6,7 @@
 using static Jameak.CursorPagination.SourceGenerator.HelperMethods;
 
 namespace Jameak.CursorPagination.SourceGenerator;
+
 internal static class OffsetPaginationClassBuilder
 {
     private const string PrivateHelperClassName = "PrivateHelper";

src/Jameak.CursorPagination.SourceGenerator/PaginationKind.cs

@@ -1,4 +1,5 @@
 namespace Jameak.CursorPagination.SourceGenerator;
+
 internal enum PaginationKind
 {
     KeySet,

src/Jameak.CursorPagination.SourceGenerator/Poco/BaseExtractedData.cs

@@ -2,6 +2,7 @@
 using Jameak.CursorPagination.SourceGenerator.Helpers;
 
 namespace Jameak.CursorPagination.SourceGenerator.Poco;
+
 internal record BaseExtractedData
 {
     public string Name { get; }

src/Jameak.CursorPagination.SourceGenerator/Poco/ExtractedKeySetData.cs

@@ -3,6 +3,7 @@
 using Jameak.CursorPagination.SourceGenerator.Helpers;
 
 namespace Jameak.CursorPagination.SourceGenerator.Poco;
+
 internal record ExtractedKeySetData : BaseExtractedData
 {
     public string? Namespace { get; }

src/Jameak.CursorPagination.SourceGenerator/Poco/ExtractedOffsetData.cs

@@ -2,6 +2,7 @@
 using Jameak.CursorPagination.SourceGenerator.Helpers;
 
 namespace Jameak.CursorPagination.SourceGenerator.Poco;
+
 internal record ExtractedOffsetData : BaseExtractedData
 {
     public string? Namespace { get; }

src/Jameak.CursorPagination.SourceGenerator/TrackingNames.cs

@@ -1,4 +1,5 @@
 namespace Jameak.CursorPagination.SourceGenerator;
+
 internal static class TrackingNames
 {
     public const string InitialOffsetExtraction = nameof(InitialOffsetExtraction);

src/Jameak.CursorPagination/InternalPaginatorHelper.cs

@@ -5,6 +5,7 @@
 using Jameak.CursorPagination.Page;
 
 namespace Jameak.CursorPagination;
+
 internal static class InternalPaginatorHelper
 {
     internal sealed record EmptyNextPageState(
@@ -99,6 +100,13 @@ internal static bool ShouldComputeTotalCount(bool hasAlreadyComputedCount, Compu
         };
     }
 
+    internal static bool CanSetTotalCountFromCurrentPageCount<T, TCursor>(List<T> pageElements, TCursor? cursor, int pageSize) where TCursor : class
+    {
+        var isFirstPage = cursor == null;
+        var pageElementsFewerThanRequested = pageElements.Count < pageSize;
+        return isFirstPage && pageElementsFewerThanRequested;
+    }
+
     internal static void ThrowIfEnumNotDefined<T>(T argument, [CallerArgumentExpression(nameof(argument))] string? paramName = null) where T : struct, Enum
     {
         if (!Enum.IsDefined(argument))

src/Jameak.CursorPagination/KeySetPaginator.cs

@@ -46,17 +46,19 @@ private static PageResult<T, TCursor> InternalApplyPagination<T, TCursor>(
         InternalPaginatorHelper.ThrowIfEnumNotDefined(computeNextPage);
         InternalPaginatorHelper.ThrowIfEnumNotDefined(computeTotalCount);
 
-        if (InternalPaginatorHelper.ShouldComputeTotalCount(totalCount.HasValue, computeTotalCount))
-        {
-            totalCount = queryable.Count();
-        }
-
         var paginatedQueryable = strategy.ApplyPagination(queryable, pageSize, computeNextPage != ComputeNextPage.Never, paginationDirection, afterCursor);
         var materialized = paginatedQueryable.ToList();
 
         strategy.PostProcessMaterializedResultInPlace(materialized, pageSize, computeNextPage != ComputeNextPage.Never, paginationDirection, out var hasNextPage);
         var (previousCursorElement, nextCursorElement) = InternalPaginatorHelper.GetCursorElements(materialized, paginationDirection);
 
+        if (InternalPaginatorHelper.ShouldComputeTotalCount(totalCount.HasValue, computeTotalCount))
+        {
+            totalCount = InternalPaginatorHelper.CanSetTotalCountFromCurrentPageCount(materialized, afterCursor, pageSize)
+                ? materialized.Count
+                : queryable.Count();
+        }
+
         NextPage<T, TCursor> NextPageGenerator(TCursor nextCursor)
         {
             return () => InternalApplyPagination(
@@ -196,17 +198,19 @@ private static async Task<PageResultAsync<T, TCursor>> InternalApplyPaginationAs
         InternalPaginatorHelper.ThrowIfEnumNotDefined(computeNextPage);
         InternalPaginatorHelper.ThrowIfEnumNotDefined(computeTotalCount);
 
-        if (InternalPaginatorHelper.ShouldComputeTotalCount(totalCount.HasValue, computeTotalCount))
-        {
-            totalCount = await asyncCountFunc(queryable, cancellationToken);
-        }
-
         var paginatedQueryable = strategy.ApplyPagination(queryable, pageSize, computeNextPage != ComputeNextPage.Never, paginationDirection, afterCursor);
         var materialized = await asyncMaterializationFunc(paginatedQueryable, cancellationToken);
 
         strategy.PostProcessMaterializedResultInPlace(materialized, pageSize, computeNextPage != ComputeNextPage.Never, paginationDirection, out var hasNextPage);
         var (previousCursorElement, nextCursorElement) = InternalPaginatorHelper.GetCursorElements(materialized, paginationDirection);
 
+        if (InternalPaginatorHelper.ShouldComputeTotalCount(totalCount.HasValue, computeTotalCount))
+        {
+            totalCount = InternalPaginatorHelper.CanSetTotalCountFromCurrentPageCount(materialized, afterCursor, pageSize)
+                ? materialized.Count
+                : await asyncCountFunc(queryable, cancellationToken);
+        }
+
         NextPageAsync<T, TCursor> NextPageAsyncGenerator(TCursor nextCursor)
         {
             return (cancellationToken) => InternalApplyPaginationAsync(

src/Jameak.CursorPagination/OffsetPaginator.cs

@@ -32,18 +32,20 @@ private static PageResult<T, OffsetCursor> InternalApplyPagination<T>(
         InternalPaginatorHelper.ThrowIfEnumNotDefined(computeNextPage);
         InternalPaginatorHelper.ThrowIfEnumNotDefined(computeTotalCount);
 
-        if (InternalPaginatorHelper.ShouldComputeTotalCount(totalCount.HasValue, computeTotalCount))
-        {
-            totalCount = queryable.Count();
-        }
-
         var paginatedQueryable = strategy.ApplyPagination(queryable, pageSize, computeNextPage != ComputeNextPage.Never, paginationDirection, afterCursor);
         var materialized = paginatedQueryable.ToList();
 
         var postProcessed = strategy.PostProcessMaterializedResult(materialized, pageSize, computeNextPage != ComputeNextPage.Never, paginationDirection, afterCursor, out var hasNextPage)
             .ToList();
         var (_, nextCursorElement) = InternalPaginatorHelper.GetCursorElements(postProcessed, paginationDirection);
 
+        if (InternalPaginatorHelper.ShouldComputeTotalCount(totalCount.HasValue, computeTotalCount))
+        {
+            totalCount = InternalPaginatorHelper.CanSetTotalCountFromCurrentPageCount(postProcessed, afterCursor, pageSize)
+                ? postProcessed.Count
+                : queryable.Count();
+        }
+
         NextPage<T, OffsetCursor> NextPageGenerator(OffsetCursor nextCursor)
         {
             return () => InternalApplyPagination(
@@ -216,11 +218,6 @@ private static async Task<PageResultAsync<T, OffsetCursor>> InternalApplyPaginat
         InternalPaginatorHelper.ThrowIfEnumNotDefined(computeNextPage);
         InternalPaginatorHelper.ThrowIfEnumNotDefined(computeTotalCount);
 
-        if (InternalPaginatorHelper.ShouldComputeTotalCount(totalCount.HasValue, computeTotalCount))
-        {
-            totalCount = await asyncCountFunc(queryable, cancellationToken);
-        }
-
         var paginatedQueryable = strategy.ApplyPagination(queryable, pageSize, computeNextPage != ComputeNextPage.Never, paginationDirection, afterCursor);
         var materialized = await asyncMaterializationFunc(paginatedQueryable, cancellationToken);
 
@@ -229,6 +226,13 @@ private static async Task<PageResultAsync<T, OffsetCursor>> InternalApplyPaginat
 
         var (_, nextCursorElement) = InternalPaginatorHelper.GetCursorElements(postProcessed, paginationDirection);
 
+        if (InternalPaginatorHelper.ShouldComputeTotalCount(totalCount.HasValue, computeTotalCount))
+        {
+            totalCount = InternalPaginatorHelper.CanSetTotalCountFromCurrentPageCount(postProcessed, afterCursor, pageSize)
+                ? postProcessed.Count
+                : await asyncCountFunc(queryable, cancellationToken);
+        }
+
         NextPageAsync<T, OffsetCursor> NextPageAsyncGenerator(OffsetCursor nextCursor)
         {
             return (cancellationToken) => InternalApplyPaginationAsync(

test/Jameak.CursorPagination.SourceGenerator.IntegrationTests/InputClasses/SimplePropertyPoco.cs

@@ -1,4 +1,5 @@
 namespace Jameak.CursorPagination.SourceGenerator.IntegrationTests.InputClasses;
+
 internal record SimplePropertyPoco
 {
     public required int IntProp { get; set; }

test/Jameak.CursorPagination.SourceGenerator.IntegrationTests/KeySetCursorSerializationTests.cs

@@ -3,6 +3,7 @@
 using Jameak.CursorPagination.SourceGenerator.IntegrationTests.PartialStrategies;
 
 namespace Jameak.CursorPagination.SourceGenerator.IntegrationTests;
+
 public class KeySetCursorSerializationTests
 {
     [Fact]

test/Jameak.CursorPagination.SourceGenerator.IntegrationTests/KeySetPaginationTests.cs

@@ -4,6 +4,7 @@
 using Jameak.CursorPagination.SourceGenerator.IntegrationTests.PartialStrategies;
 
 namespace Jameak.CursorPagination.SourceGenerator.IntegrationTests;
+
 public class KeySetPaginationTests
 {
     private static void AssertStrategyOrdersCorrectly<TCursor>(

test/Jameak.CursorPagination.SourceGenerator.IntegrationTests/OffsetCursorSerializationTests.cs

@@ -2,6 +2,7 @@
 using Jameak.CursorPagination.Abstractions.OffsetPagination;
 
 namespace Jameak.CursorPagination.SourceGenerator.IntegrationTests;
+
 public class OffsetCursorSerializationTests
 {
     [Fact]

test/Jameak.CursorPagination.SourceGenerator.IntegrationTests/OffsetPaginationTests.cs

@@ -4,6 +4,7 @@
 using Jameak.CursorPagination.SourceGenerator.IntegrationTests.PartialStrategies;
 
 namespace Jameak.CursorPagination.SourceGenerator.IntegrationTests;
+
 public class OffsetPaginationTests
 {
     private static void AssertStrategyOrdersCorrectly(

test/Jameak.CursorPagination.SourceGenerator.IntegrationTests/TestHelper.cs

@@ -5,6 +5,7 @@
 using Jameak.CursorPagination.SourceGenerator.IntegrationTests.InputClasses;
 
 namespace Jameak.CursorPagination.SourceGenerator.IntegrationTests;
+
 internal class TestHelper
 {
     public static IEnumerable<SimplePropertyPoco> InfiniteGenerator()

test/Jameak.CursorPagination.SourceGenerator.Tests/ErrorTests.cs

@@ -1,4 +1,5 @@
 namespace Jameak.CursorPagination.SourceGenerator.Tests;
+
 public class ErrorTests
 {
     private const string ValidPaginatedType = """

test/Jameak.CursorPagination.SourceGenerator.Tests/FullNameOfDiagnosticAnalyzerTests.cs

@@ -1,6 +1,7 @@
 using Jameak.CursorPagination.SourceGenerator.Analyzers;
 
 namespace Jameak.CursorPagination.SourceGenerator.Tests;
+
 public class FullNameOfDiagnosticAnalyzerTests
 {
     [Fact]

test/Jameak.CursorPagination.SourceGenerator.Tests/GeneralTests.cs

@@ -1,4 +1,5 @@
 namespace Jameak.CursorPagination.SourceGenerator.Tests;
+
 public class GeneralTests
 {
     [Fact]

test/Jameak.CursorPagination.SourceGenerator.Tests/InternalUsageAnalyzerTests.cs

@@ -1,4 +1,5 @@
 namespace Jameak.CursorPagination.SourceGenerator.Tests;
+
 public class InternalUsageAnalyzerTests
 {
     [Fact]

test/Jameak.CursorPagination.SourceGenerator.Tests/KeySetSpecificTests.cs

@@ -1,4 +1,5 @@
 namespace Jameak.CursorPagination.SourceGenerator.Tests;
+
 public class KeySetSpecificTests
 {
     private static readonly string s_paginatedType = """

test/Jameak.CursorPagination.SourceGenerator.Tests/ModuleInitializer.cs

@@ -1,6 +1,7 @@
 using System.Runtime.CompilerServices;
 
 namespace Jameak.CursorPagination.SourceGenerator.Tests;
+
 internal static class ModuleInitializer
 {
     [ModuleInitializer]

test/Jameak.CursorPagination.SourceGenerator.Tests/NestedPropertyTests.cs

@@ -1,4 +1,5 @@
 namespace Jameak.CursorPagination.SourceGenerator.Tests;
+
 public class NestedPropertyTests
 {
     [Fact]

test/Jameak.CursorPagination.SourceGenerator.Tests/NullableTests.cs

@@ -1,4 +1,5 @@
 namespace Jameak.CursorPagination.SourceGenerator.Tests;
+
 public class NullableTests
 {
     [Fact]

test/Jameak.CursorPagination.SourceGenerator.Tests/OffsetSpecificTests.cs

@@ -1,4 +1,5 @@
 namespace Jameak.CursorPagination.SourceGenerator.Tests;
+
 public class OffsetSpecificTests
 {
     private static readonly string s_paginatedType = """

test/Jameak.CursorPagination.Tests/AsyncDelegates.cs

@@ -1,4 +1,5 @@
 namespace Jameak.CursorPagination.Tests;
+
 internal class AsyncDelegates
 {
     public static Task<List<T>> SyncToList<T>(IQueryable<T> queryable)

test/Jameak.CursorPagination.Tests/DbClasses/DatabaseFixture.cs

@@ -2,6 +2,7 @@
 using Microsoft.EntityFrameworkCore;
 
 namespace Jameak.CursorPagination.Tests.DbClasses;
+
 public sealed class DatabaseFixture : IDisposable
 {
     private readonly SqliteConnection _connection;

test/Jameak.CursorPagination.Tests/DbClasses/TestDbContext.cs

@@ -2,6 +2,7 @@
 using Microsoft.EntityFrameworkCore;
 
 namespace Jameak.CursorPagination.Tests.DbClasses;
+
 public class TestDbContext : DbContext
 {
     private readonly List<string> _logMessages = [];

test/Jameak.CursorPagination.Tests/InputClasses/NullablePropertyWithDbComputedColumnPoco.cs

@@ -1,6 +1,7 @@
 using Microsoft.EntityFrameworkCore;
 
 namespace Jameak.CursorPagination.Tests.InputClasses;
+
 [PrimaryKey(nameof(PrimaryKeyInt))]
 [Index(nameof(ComputedIntProp))]
 public record NullablePropertyWithDbComputedColumnPoco