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Search results 1..6 of 6 for: shm

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 ... 
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 ... 
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 ... 

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