https://tekinali.com/en/ Computer Engineer · .NET, iOS & NLP en https://tekinali.com/en/blog/first-row-per-group-sql https://tekinali.com/en/blog/first-row-per-group-sql Wed, 21 Oct 2026 00:00:00 GMT A guide to selecting the first or top-N row per group in SQL Server, PostgreSQL, EF Core and Spark: how each pattern executes, why data distribution decides which one wins, which indexes they need, and how to verify the choice in the plan. sql sql-server postgresql performance https://tekinali.com/en/blog/calling-async-from-sync-csharp https://tekinali.com/en/blog/calling-async-from-sync-csharp Tue, 13 Oct 2026 00:00:00 GMT How blocking on a Task deadlocks UI apps and starves the thread pool in ASP.NET Core, what to do when blocking is unavoidable, where ConfigureAwait(false) and .NET 8's ConfigureAwaitOptions matter, and how hidden async void crashes processes. dotnet csharp async https://tekinali.com/en/blog/upsert-sql-server-postgresql-sqlite-guide https://tekinali.com/en/blog/upsert-sql-server-postgresql-sqlite-guide Mon, 12 Oct 2026 00:00:00 GMT How upserts break under concurrency and how to write them safely: UPDLOCK and SERIALIZABLE or MERGE in SQL Server, ON CONFLICT, MERGE and RETURNING in PostgreSQL, native UPSERT in SQLite, and why INSERT OR REPLACE is not one. sql sql-server postgresql sqlite https://tekinali.com/en/blog/spark-repartition-vs-coalesce-aqe https://tekinali.com/en/blog/spark-repartition-vs-coalesce-aqe Wed, 23 Sep 2026 00:00:00 GMT How partition count shapes Spark performance, what repartition() and coalesce() really do, why coalesce(1) can push a whole job onto one task, and how Adaptive Query Execution (on by default since Spark 3.2) handles most partition tuning at runtime. spark pyspark performance https://tekinali.com/en/blog/why-nolock-is-still-wrong https://tekinali.com/en/blog/why-nolock-is-still-wrong Thu, 17 Sep 2026 00:00:00 GMT How NOLOCK really behaves (dirty reads, skipped and duplicated rows, error 601), how RCSI and SNAPSHOT isolation replace it, and what SQL Server 2025 optimized locking adds on top, including its limits. sql-server concurrency performance https://tekinali.com/en/blog/swift-6-2-main-thread-and-weak-self https://tekinali.com/en/blog/swift-6-2-main-thread-and-weak-self Wed, 09 Sep 2026 00:00:00 GMT How Swift 6.2's default main-actor isolation, nonisolated(nonsending) and @concurrent change where your code runs, why async does not mean background, and when [weak self] in a Task still matters. ios swift concurrency https://tekinali.com/en/blog/ios-keyboard-covering-text-field https://tekinali.com/en/blog/ios-keyboard-covering-text-field Sat, 05 Sep 2026 00:00:00 GMT How the software keyboard interacts with your layout, and the modern tools for it: UIKeyboardLayoutGuide in UIKit, the keyboard safe area in SwiftUI, and @FocusState, onSubmit and scrollDismissesKeyboard for focus and dismissal. ios uikit swiftui https://tekinali.com/en/blog/passing-data-between-screens-observable https://tekinali.com/en/blog/passing-data-between-screens-observable Thu, 03 Sep 2026 00:00:00 GMT Passing data forward and back between UIKit view controllers without singletons, sharing state in SwiftUI with @Observable, @State, @Environment and @Bindable, value-based navigation, and what changed about @State initial values in Xcode 27. ios swift uikit swiftui https://tekinali.com/en/blog/how-this-site-works https://tekinali.com/en/blog/how-this-site-works Thu, 27 Aug 2026 00:00:00 GMT Why I put my CV inside an IDE and a real SQLite database, and how the SQL console below is kept safe. dotnet sqlite security https://tekinali.com/en/blog/sqlite-insert-performance-ios https://tekinali.com/en/blog/sqlite-insert-performance-ios Sat, 22 Aug 2026 00:00:00 GMT Why SQLite bulk inserts are slow by default, the three techniques that fix it, what synchronous=OFF and journal_mode=MEMORY really risk, why WAL with synchronous=NORMAL is a safer default, and how it all applies to Core Data, SwiftData and .NET. sqlite ios dotnet performance https://tekinali.com/en/blog/transient-scoped-singleton-captive-dependency https://tekinali.com/en/blog/transient-scoped-singleton-captive-dependency Thu, 20 Aug 2026 00:00:00 GMT What transient, scoped and singleton really mean, how a scoped DbContext gets trapped in a singleton, how scope validation catches it, and how to handle background services, thread safety, keyed services (.NET 8) and HttpClient lifetimes. dotnet aspnet-core dependency-injection https://tekinali.com/en/blog/ef-core-bulk-insert-update-delete https://tekinali.com/en/blog/ef-core-bulk-insert-update-delete Tue, 18 Aug 2026 00:00:00 GMT How EF Core's batched SaveChanges differs from the EF6-era approach, how ExecuteUpdate/ExecuteDelete work and where they bite, EF Core 10's conditional setters, SqlQuery for unmapped types, and when to switch to SqlBulkCopy or PostgreSQL COPY. dotnet efcore performance https://tekinali.com/en/blog/openai-api-token-counting-conversation-state https://tekinali.com/en/blog/openai-api-token-counting-conversation-state Sun, 16 Aug 2026 00:00:00 GMT How the OpenAI API has changed, how to count input tokens before a request, three ways to keep conversation state (manual replay, previous_response_id, Conversations API), and how to tell quota errors from rate limits on a 429, with Python and C# examples. openai ai python dotnet