SQLite 衍生 wal/shm 檔案

資料來源: https://sqlite.org/wal.html

https://filext.com/file-extension/SQLITE-SHM

01.wal file(Write-Ahead Logging): The default method by which SQLite implements atomic commit and rollback is a rollback journal. Beginning with version 3.7.0 (2010-07-21), a new “Write-Ahead Log” option (hereafter referred to as “WAL”) is available.

[SQLite 實現原子提交和回滾的默認方法 是回滾日誌。從版本 3.7.0 (2010-07-21) 開始，可以使用新的“Write-Ahead Log”選項（以下簡稱“WAL”）]

02.shm file(SQLITE-SHM file): SQLITE-SHM files mostly belong to SQLite by SQLite Consortium. The .db-shm file is a shared memory file created by SQLite that contains only temporary data. It is only present when SQLite it running in WAL (Write-Ahead Log) mode. This is because in WAL mode, db connections sharing the same db file must all update the same memory location used as index for the WAL file, to prevent conflicts. SQLite is a software library that implements a self-contained, serverless, zero-configuration, transactional SQL database engine. SQLite is widely deployed. It is used in many desktop computer applications as well as consumer electronic devices including cellphones, PDAs, and MP3 players. For example, Mozilla’s Sunbird/Lightning calendaring programs use SQLite databases.

[SQLITE-SHM 文件大多屬於SQLite Consortium 的 SQLite。.db-shm 文件是由 SQLite 創建的共享內存文件，僅包含臨時數據。它僅在 SQLite 在 WAL（預寫日誌）模式下運行時出現。這是因為在 WAL 模式下，共享同一個 db 文件的 db 連接必須全部更新用作 WAL 文件索引的相同內存位置，以防止衝突。SQLite 是一個實現自包含、無服務器、零配置、事務性 SQL 數據庫引擎的軟件庫。SQLite 被廣泛部署。它用於許多台式計算機應用以及消費電子設備，包括手機、PDA 和 MP3 播放器。例如，Mozilla 的 Sunbird/Lightning 日曆程序使用 SQLite 數據庫。]