C API: Mutexes
(c3ref/mutex_alloc.html)
sqlite3_mutex_alloc(), sqlite3_mutex_free(), sqlite3_mutex_enter(), sqlite3_mutex_try(), sqlite3_mutex_leave()
... SQLITE_MUTEX_PTHREADS
SQLITE_MUTEX_W32
SQLITE_MUTEX_NOOP
The SQLITE_MUTEX_NOOP implementation is a set of routines
that does no real locking and is appropriate for use in
a single-threaded application. The SQLITE_MUTEX_PTHREADS and
SQLITE_MUTEX_W32 implementations are appropriate for use on Unix
and Windows.
If ...
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Database File Format
(fileformat.html)
1.4. The Lock-Byte Page
The lock-byte page is the single page of the database file
that contains the bytes at offsets between 1073741824 and 1073742335,
inclusive. A database file that is less than or equal to 1073741824 bytes
in size contains no lock ...
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Appropriate Uses For SQLite
(whentouse.html)
2. Situations Where A Client/Server RDBMS May Work Better
... Also, file locking logic is buggy in
many network filesystem implementations (on both Unix and Windows).
If file locking does not work correctly,
two or more clients might try to modify the
same part of the same database at the ...
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VACUUM
(lang_vacuum.html)
... VACUUM (but not VACUUM INTO) is a write operation and so if another
database connection is holding a lock that prevents writes, then
the VACUUM will fail.
An alternative to using the VACUUM command to
reclaim space after data has ...
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Temporary Files Used By SQLite
(tempfiles.html)
2.1. Rollback Journals
... If an application puts SQLite in
exclusive locking mode using
the pragma:
PRAGMA locking_mode=EXCLUSIVE;
SQLite creates a new rollback journal at the start of the first
transaction within an exclusive locking mode session. But at the
conclusion of the ...
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The DBSTAT Virtual Table
(dbstat.html)
1. Overview
... Freelist pages, pointer-map pages, and the lock page are omitted from
the analysis.
By default, there is a single row in the DBSTAT table for each
btree page the database file. Each row provides
information about the space utilization ...
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Architecture of SQLite
(arch.html)
... The page cache also provides the rollback and atomic commit abstraction
and takes care of locking of the database file. The
B-tree driver requests particular pages from the page cache and notifies
the page cache when it wants to ...
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The SQLite R*Tree Module
(rtree.html)
3.5. Reading And Writing At The Same Time
... Attempts to do so
will fail with a SQLITE_LOCKED "database table is locked" error.
So, for example, suppose an application runs one query against an R-Tree like
this:
SELECT id FROM demo_index
WHERE maxY>=35.0 AND minY ...
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Distinctive Features Of SQLite
(different.html)
... 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 ...
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The SQLite Bytecode Engine
(opcode.html)
4. The Opcodes
... A readlock is obtained if P3==0 or
a write lock if P3==1.
P2 contains the root-page of the table to lock.
P4 contains a pointer to the name of the table being locked. This is only
used ...
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