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+<div class=fancy>
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+SQLite Is Serverless
+</div>
+</div>
+
+
+
+
+
+<h1 id="sqlite_is_serverless"><span>1. </span>SQLite Is Serverless</h1>
+
+<p>
+Most SQL database engines are implemented as a separate server process.
+Programs that want to access the database communicate with the server
+using some kind of interprocess communication (typically TCP/IP) to send
+requests to the server and to receive back results.
+SQLite does not work this way.
+With SQLite, the process that wants to access the database reads and
+writes directly from the database files on disk.
+There is no intermediary server process.
+</p>
+
+<p>
+There are advantages and disadvantages to being serverless.
+The main advantage is that there is no separate server process
+to install, setup, configure, initialize, manage, and troubleshoot.
+This is one reason why SQLite is a
+"<a href="zeroconf.html">zero-configuration</a>" database engine.
+Programs that use SQLite require no administrative support for
+setting up the database engine before they are run.
+Any program that is able to access the disk is able to use an SQLite database.
+</p>
+
+<p>
+On the other hand, a database engine that uses a server can
+provide better protection from bugs in the client
+application - stray pointers in a client cannot corrupt memory
+on the server.
+And because a server is a single persistent process,
+it is able to control database access with more precision,
+allowing for finer-grained locking and better concurrency.
+</p>
+
+<p>
+Most SQL database engines are client/server based.
+Of those that are serverless, SQLite is the only one
+known to this author that allows multiple applications
+to access the same database at the same time.
+</p>
+
+<h1 id="classic_serverless_vs_neo_serverless"><span>2. </span>Classic Serverless Vs. Neo-Serverless</h1>
+
+<p>
+<i>(This section was added on 2018-04-02)</i>
+
+</p><p>
+Recently, folks have begun to use the
+word "serverless" to mean something subtly different from its intended
+meaning in this document. Here are two possible definitions of "serverless":
+
+</p><ol>
+<li><p>
+<b>Classic Serverless:</b>
+The database engine runs within the same process, thread, and address space
+as the application. There is no message passing or network activity.
+
+</p></li><li><p>
+<b>Neo-Serverless:</b>
+The database engine runs in a separate namespace from the application,
+probably on a separate machine, but the database is provided as a
+turn-key service by the hosting provider, requires no management or
+administration by the application owners, and is so easy to use
+that the developers can think of the database as being serverless
+even if it really does use a server under the covers.
+</p></li></ol>
+
+<p>
+SQLite is an example of a classic serverless database engine.
+With SQLite, there are no other processes, threads, machines, or
+other mechanisms (apart from host computer OS and filesystem)
+to help provide database services or implementation. There really
+is no server.
+
+</p><p>
+<a href="https://docs.microsoft.com/en-us/azure/cosmos-db/serverless-computing-database">Microsoft Azure Cosmo DB</a>
+and
+<a href="https://aws.amazon.com/s3/">Amazon S3</a>
+are examples of a neo-serverless databases.
+These database are implemented by server processes running separately
+in the cloud.
+But the servers are maintained and administered by the ISP, not by
+the application developer.
+Application developers just use the service. Developers do not have to
+provision, configure, or manage database server instances, as all of that
+work is handled automatically by the service provider. Database servers
+do in fact exist, they are just hidden from the developers.
+
+</p><p>
+It is important to understand these two different definitions for
+"serverless".
+When a database claims to be "serverless",
+be sure to discern whether they mean "classic serverless"
+or "neo-serverless".
+</p><p align="center"><small><i>This page last modified on <a href="https://sqlite.org/docsrc/honeypot" id="mtimelink" data-href="https://sqlite.org/docsrc/finfo/pages/serverless.in?m=b6f6dbff74f67a539">2018-04-02 15:25:54</a> UTC </small></i></p>
+