Overriding LIKE Function Disables Index Optimization in SQLite When you override the default LIKE function in SQLite using sqlite3_create_function_v2(), the query optimizer can no longer utilize indexes for pattern matching queries. This behavior is by design, as SQLite cannot guarantee that the custom LIKE function adheres to the same semantics as the built-in LIKE function….
SQLite Security Vulnerabilities and CVE Misreporting SQLite, a widely-used embedded database engine, has faced numerous reported Common Vulnerabilities and Exposures (CVEs) over the years. These CVEs often stem from misunderstandings about SQLite’s architecture, its intended use cases, and the context in which vulnerabilities are discovered. Many of these reported vulnerabilities are either irrelevant to production…
Visibility Delays in Committed Changes Across ATTACHed Databases When working with SQLite databases in WAL (Write-Ahead Logging) mode, particularly in scenarios where multiple processes attach and query databases from other processes, understanding the visibility of committed changes is crucial. In this context, a common issue arises where committed transactions in one process are not immediately…
NULL vs. Empty String: The Hidden Culprit in Query Results When working with SQLite, one of the most common yet subtle issues developers encounter is the distinction between NULL and an empty string (”). These two entities, while seemingly similar, behave differently in SQL operations, particularly in comparisons. This discrepancy can lead to unexpected query…
SQLite Extension Loading Failure Due to Entry Point Mismatch When attempting to load a custom SQLite extension on Windows, a common issue arises where the sqlite3_load_extension function fails with the error message: "The specified procedure cannot be found." This error typically occurs when the entry point function in the dynamically linked library (DLL) does not…
SQLite DLL Version Discrepancy on Windows 10 When working with the built-in SQLite DLL (winsqlite3.dll) on Windows 10, users may encounter a version discrepancy that raises questions about compatibility and functionality. The DLL provided by Windows 10 is labeled as version 3.23.2, which does not correspond to any official release listed on the SQLite website….
LEFT OUTER JOIN Returning Incorrect Counts in SQLite 3.31 The issue at hand revolves around the incorrect results returned by LEFT OUTER JOIN queries in SQLite version 3.31. Specifically, when joining two tables—users and forwarding_addresses—on a common column (user_id), the query returns an unexpected count when filtering on both the forwarding_addresses.user_id and users.id columns. This…
SQLite Database Page Allocation and Percentage of Total Database When working with SQLite, understanding how the database engine allocates pages and calculates the percentage of total database usage is crucial for effective database management and optimization. SQLite is a lightweight, file-based database engine that uses a fixed-size page-based storage system. Each database file is divided…
LSM1’s Inability to Perform Partial Read/Write Operations The core issue revolves around the LSM1 storage engine’s limitation in handling partial read and write operations for values stored within the database. Unlike SQLite’s Blob I/O API, which allows for efficient partial access to large binary objects (BLOBs), LSM1 currently only supports fetching entire values. This limitation…
In-Memory Shared Database Creation Fails with Mono.Data.Sqlite Creating an in-memory shared database using Mono.Data.Sqlite can be a challenging task, especially when the database is unexpectedly created on the local hard drive instead of in memory. This issue often arises due to misconfigurations in the connection string or underlying library settings. The primary goal is to…