Small. Fast. Reliable.
Choose any three.
Choose any three.
|
WAL-mode File Format
(walformat.html)
1.3. The Wal-Index or "-shm" file
The wal-index file or "shm" file is not actually used as a file.
Rather, individual database clients mmap the shm file and use it
as shared memory for coordinating access to the database and as a cache
for quickly ...
|
|
8+3 Filenames
(shortnames.html)
... Similarly, "app.db-wal" will become "app.wal" and
"app.db-shm" becomes "app.shm".
Note that it is very important that the database filename have some kind
of extension. If there is no extension, then SQLite creates auxiliary
filenames ...
|
|
Write-Ahead Logging
(wal.html)
1. Overview
... The opening process must have write privileges for "-shm"
wal-index shared memory file associated with the database, if that
file exists, or else write access on the directory containing
the database file if the "-shm" file does not exist ...
|
|
C API: Standard File Control Opcodes
(c3ref/c_fcntl_begin_atomic_write.html)
SQLITE_FCNTL_LOCKSTATE, SQLITE_FCNTL_GET_LOCKPROXYFILE, SQLITE_FCNTL_SET_LOCKPROXYFILE, SQLITE_FCNTL_LAST_ERRNO, SQLITE_FCNTL_SIZE_HINT, SQLITE_FCNTL_CHUNK_SIZE ...
... The SQLITE_FCNTL_CKPT_DONE opcode is invoked from within a checkpoint
in wal mode after the client has finished copying pages from the wal
file to the database file, but before the *-shm file is updated to
record the fact that the ...
|
|
Temporary Files Used By SQLite
(tempfiles.html)
2.3. Shared-Memory Files
... The shared-memory file, if it exists, is located
in the same directory as the database file and has the same name as the
database file except with the 4 characters "-shm" appended.
Shared memory files only exist while running ...
|
|
Result and Error Codes
(rescode.html)
6. Result Code Meanings
... SQLITE_IOERR indicating an I/O error
within the xShmMap method on the sqlite3_io_methods object
while trying to enlarge a "shm" file as part of
WAL mode transaction processing. This error may indicate that
the underlying filesystem volume is out of ...
|
|
Compile-time Options
(compile.html)
7. Options To Enable Features Normally Turned Off
... SEH is used to intercept errors that might
occur while accessing the memory-mapped shm file that are part of
WAL mode processing. If the operating system raised errors while SQLite
is trying to access the shm file, this option ...
|
|
Database File Format
(fileformat.html)
4.6. WAL-Index Format
... The memory-mapped
file is in the same directory as the database and has the same name
as the database with a "-shm" suffix appended. Because
the wal-index is shared memory, SQLite does not support
journal_mode=WAL
on a ...
|
Page generated by FTS5 in about 13.00 ms.