... The SQL command "BEGIN TRANSACTION" (the TRANSACTION keyword is optional) is used to take SQLite out of autocommit mode. Note that the BEGIN command does not acquire any locks on the database. After a BEGIN command, a SHARED lock will ... 

 ... However concurrency is reduced as follows: When a connection using asynchronous IO begins a database transaction, the database is locked immediately. However the lock is not released until after all relevant operations in the write-queue have been flushed to ... 

Isolation In SQLite The "isolation" property of a database determines when changes made to the database by one operation become visible to other concurrent operations. Isolation Between Database Connections If the same database is being read and written using two ... 

2.2. Concurrency When a read operation begins on a WAL-mode database, it first remembers the location of the last valid commit record in the WAL. Call this point the "end mark". Because the WAL can be growing and adding new commit ... 

 ... A basic understanding of the normal SQLite locking model (see File Locking And Concurrency In SQLite Version 3 for details) is assumed. 1.1. Use of shared-cache is discouraged Shared-cache mode is an obsolete feature. The use of ... 

sqlite3_wal_checkpoint_v2()

 ... On the other hand, passive mode might leave the checkpoint unfinished if there are concurrent readers or writers. SQLITE_CHECKPOINT_FULL This mode blocks (it invokes the busy-handler callback) until there is no database writer and all readers are reading from ... 

sqlite3_open(), sqlite3_open16()

 ... Future versions of SQLite might make use of additional special filenames that begin with the ":" character. It is recommended that when a database filename actually does begin with a ":" character you should prefix the filename with a pathname such as ... 

 ... Improved Concurrency SQLite version 2.8 allowed multiple simultaneous readers or a single writer but not both. SQLite version 3.0 allows one process to begin writing the database while other processes continue to read. The writer must still obtain ... 

 ... Atomically releases the mutex and begins waiting for the asynchronous signal. When the signal arrives, continue. This way, it doesn't matter if the unlock-notify callback has already been invoked, or is being invoked, when the wait_for_unlock_notify() thread begins ... 

 ... And because a server is a single persistent process, it is able control database access with more precision, allowing for finer grain locking and better concurrency. Most SQL database engines are client/server based. Of those that are serverless, SQLite ...