Issue Overview: FTS5 External Content Table Deletion Mechanics and Order Dependency When working with SQLite’s FTS5 virtual tables configured to use external content (via the content= option), managing deletions requires a nuanced understanding of how the full-text search index interacts with the underlying source data. The core challenge arises when attempting to delete records from…
Understanding the Foreign Key Constraint Error Message When working with SQLite, one of the most common errors encountered is the "FOREIGN KEY constraint failed" message. This error occurs when an operation violates a foreign key constraint, typically during a DELETE or UPDATE operation that would leave a child table with orphaned rows. The error message,…
Understanding FTS5 External Content Index Integrity Requirements The core challenge arises when using SQLite’s FTS5 module with external content tables—specifically, scenarios where the virtual table’s internal rowid becomes desynchronized from the content_rowid column of the source table. This mismatch leads to intermittent "database disk image is malformed" errors during query execution, even when the database…
Memory Database Initialization and sqlite3_prepare() Failure The core issue revolves around the failure of the sqlite3_prepare() function when using an in-memory SQLite database, while the same code works flawlessly with a file-based database. The error manifests as a CppSQLite3Exception being thrown, indicating a problem during the preparation of the SQL statement. This issue is particularly…
Primary Key Index Mismatch and Query Plan Inconsistency in SQLite Issue Overview: Unexpected Missing Rows When Filtering by Integer Primary Key The core issue involves a scenario where rows present in a SQLite table are not returned when queried via an equality filter (WHERE PK = <value>) that leverages a user-created unique index. However, the…
Issue Overview: Decimal Precision and Floating-Point Arithmetic in SQLite SQLite, like many other database systems, relies on IEEE 754 floating-point arithmetic for handling decimal numbers. This standard is widely used due to its efficiency and compatibility with modern hardware. However, it introduces certain limitations and nuances, particularly when dealing with decimal precision and comparisons. The…
Core Performance Impact of Windows Core Isolation on SQLite Operations Issue Overview: Severe SQLite Import Slowdown Linked to Core Isolation Activation A user observed a dramatic increase in SQLite database import time from 2 hours to 18 hours for a 41 GB database. The import process, executed via a C# .NET 7.0 application on Windows…
Issue Overview: SQLite3 Exec Returning SQLITE_MISUSE Due to Invalid DB Handle The core issue revolves around the sqlite3_exec() function returning the SQLITE_MISUSE error code (21) when attempting to execute an SQL statement. The error is likely caused by the misuse of the SQLite database handle (sqlite3*), which is either invalid, closed prematurely, or corrupted. The…
Understanding Connection Pooling in SQLite and Its Misconceptions Connection pooling is a concept that is often misunderstood, especially when applied to SQLite. In traditional client-server databases like MySQL or PostgreSQL, connection pooling is a critical optimization technique. It reduces the overhead of repeatedly opening and closing connections to the database server, which can be resource-intensive….
Understanding Readonly WAL Mode Behavior and Residual File Retention The interaction between SQLite’s write-ahead logging (WAL) mode and read-only database connections creates operational nuances that frequently surprise developers. When a database connection explicitly specifies the -readonly flag (or equivalent API parameters), residual -wal and -shm files may persist after connection closure despite the absence of…