Feature/static caching (#26)

* Added a decorator to statically cache schema and calculated dependencies * Upped pre-release version
carl-berg · Feb 21, 2023 · 4ea286d · 4ea286d
1 parent d3f9624
commit 4ea286d
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Showing 3 changed files with 60 additions and 4 deletions.
diff --git a/DataDude/DataDude.csproj b/DataDude/DataDude.csproj
@@ -4,7 +4,7 @@
     <TargetFramework>netstandard2.1</TargetFramework>
     <LangVersion>9.0</LangVersion>
     <Nullable>enable</Nullable>
-    <Version>0.8.0-preview.2</Version>
+    <Version>0.8.0-preview.3</Version>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
     <IncludeSymbols>true</IncludeSymbols>
     <SymbolPackageFormat>snupkg</SymbolPackageFormat>

diff --git a/DataDude/DataDudeContext.cs b/DataDude/DataDudeContext.cs
@@ -12,7 +12,9 @@ namespace DataDude
 {
     public class DataDudeContext
     {
+        internal const string SchemaKey = "Schema";
         private Dictionary<string, object> _store;
+
         public DataDudeContext(ISchemaLoader schemaLoader)
         {
             _store = new Dictionary<string, object>();
@@ -60,7 +62,7 @@ public DataDudeContext(ISchemaLoader schemaLoader)
 
         public IEnumerable<string> ContextKeys => _store.Keys;
 
-        public SchemaInformation? Schema => Get<SchemaInformation>("Schema");
+        public SchemaInformation? Schema => Get<SchemaInformation>(SchemaKey);
 
         public static DbType GetDbType(ColumnInformation column)
         {
@@ -96,10 +98,10 @@ public void Set<T>(string key, T value)
 
         public async ValueTask LoadSchema(DbConnection connection, DbTransaction? transaction = null)
         {
-            if (_store.ContainsKey("Schema") is false)
+            if (_store.ContainsKey(SchemaKey) is false)
             {
                 var schema = await SchemaLoader.Load(connection, transaction);
-                Set("Schema", schema);
+                Set(SchemaKey, schema);
             }
         }
     }

diff --git a/DataDude/Instructions/StaticCache.cs b/DataDude/Instructions/StaticCache.cs
@@ -0,0 +1,54 @@
+using System.Collections.Generic;
+using System.Linq;
+using DataDude.Schema;
+using System.Threading.Tasks;
+
+namespace DataDude.Instructions
+{
+    /// <summary>
+    /// Attempting to speed up DataDude by statically caching and pre-loading sql schema and calculated dependencies in between runs
+    /// Warning: This is an experimental feature
+    /// </summary>
+    public class StaticCache : IInstructionDecorator
+    {
+        public StaticCache(DataDudeContext context)
+        {
+            if (Schema is { })
+            {
+                // Pre-load schema
+                context.Set(DataDudeContext.SchemaKey, Schema);
+            }
+
+            foreach (var (cacheKey, dependencyCache) in Dependencies)
+            {
+                // Pre-load calculated dependencies
+                context.Set(cacheKey, dependencyCache);
+            }
+        }
+
+        protected static SchemaInformation? Schema { get; set; }
+        protected static Dictionary<string, IDictionary<TableInformation, IReadOnlyList<TableInformation>>> Dependencies { get; set; } = new();
+
+        public ValueTask PreProcess(DataDudeContext context) => default;
+
+        public ValueTask PostProcess(DataDudeContext context)
+        {
+            if (Schema is null)
+            {
+                // Cache loaded schema
+                Schema = context.Schema;
+            }
+
+            // Cache calculated dependencies
+            foreach (var cacheKey in context.ContextKeys.Where(key => key.StartsWith(DependencyService.CachePrefix) && Dependencies.ContainsKey(key) is false))
+            {
+                if (context.Get<IDictionary<TableInformation, IReadOnlyList<TableInformation>>>(cacheKey) is { } createdCache)
+                {
+                    Dependencies[cacheKey] = createdCache;
+                }
+            }
+
+            return default;
+        }
+    }
+}