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What is concurrent access by multiple users?
A. The ability to gain admittance to a system or component by more than one user or process. For example, concurrent access to a computer means multiple users are interacting with the system simultaneously.
How many concurrent users can SQLite handle?
There is no limit for open connections built into SQLite because there is no part of SQLite which counts open connections. You can have as many as you have memory available, file handles available, or any other resource the operating system needs. Whatever it is, it’s a high number rather than something like 10.
What is Spatialite Qgis?
While PostGIS is generally used on a server to provide spatial database capabilities to multiple users at the same time, QGIS also supports the use of a file format called spatialite that is a lightweight, portable way to store an entire spatial database in a single file.
What is concurrent access in database?
Concurrent database access refers to the situation where the database is being accessed from more than one connection (user) at a time. Without the database system exerting some control over what gets updated by who and when, all kinds of data integrity and consistency problems can arise.
How does concurrent access work in SQLite concurrent access?
Together they are present in begin-concurrent-wal2 or each in a separate own branch. SQLite has a readers-writer lock on the database level. Multiple connections (possibly owned by different processes) can read data from the same database at the same time, but only one can write to the database.
What does it mean to have multiple readers in SQLite?
SQLite has a readers-writer lock on the database level. Multiple connections (possibly owned by different processes) can read data from the same database at the same time, but only one can write to the database. SQLite supports an unlimited number of simultaneous readers, but it will only allow one writer at any instant in time.
How are multiple connections able to read from the same database?
In order to be able to read (not write) data from the database, the connection must first enter the SHARED state, by getting a SHARED lock. Multiple connections can obtain and maintain SHARED locks at the same time, so multiple connections can read data from the same database at the same time.
When does a connection to a database become shared?
The initial state is UNLOCKED, and in this state, the connection has not accessed the database yet. When a process is connected to a database and even a transaction has been started with BEGIN, the connection is still in the UNLOCKED state. After the UNLOCKED state, the next state is the SHARED state.