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Disable the use of memory-mapped I/O if the SQLITE_DISABLE_MMAP macro is

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defined.  Automatically define this macro for OpenBSD and QNX.  Other
systems are likely to be added to the disabled list over time.

FossilOrigin-Name: 8a4314a398c6c6efb25e6993c826b7e60d9bb1f9
This commit is contained in:
drh
2013-04-08 20:47:49 +00:00
parent f90e50f60b
commit 188d488409
14 changed files with 86 additions and 25 deletions
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20
src/pager.c
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@@ -770,6 +770,16 @@ static const unsigned char aJournalMagic[] = {
# define MEMDB pPager->memDb
#endif
/*
** The macro USEFETCH is true if we are allowed to use the xFetch and xUnfetch
** interfaces to access the database using memory-mapped I/O.
*/
#ifdef SQLITE_DISABLE_MMAP
# define USEFETCH(x) 0
#else
# define USEFETCH(x) ((x)->bUseFetch)
#endif
/*
** The maximum legal page number is (2^31 - 1).
*/
@@ -3090,7 +3100,7 @@ static int pagerBeginReadTransaction(Pager *pPager){
rc = sqlite3WalBeginReadTransaction(pPager->pWal, &changed);
if( rc!=SQLITE_OK || changed ){
pager_reset(pPager);
if( pPager->bUseFetch ) sqlite3OsUnfetch(pPager->fd, 0, 0);
if( USEFETCH(pPager) ) sqlite3OsUnfetch(pPager->fd, 0, 0);
}
return rc;
@@ -3356,6 +3366,7 @@ void sqlite3PagerSetCachesize(Pager *pPager, int mxPage){
** Invoke SQLITE_FCNTL_MMAP_LIMIT based on the current value of mxMmap.
*/
static void pagerFixMaplimit(Pager *pPager){
#if !defined(SQLITE_DISABLE_MMAP)
sqlite3_file *fd = pPager->fd;
if( isOpen(fd) ){
sqlite3_int64 mx;
@@ -3363,6 +3374,7 @@ static void pagerFixMaplimit(Pager *pPager){
mx = pPager->mxMmap;
sqlite3OsFileControlHint(pPager->fd, SQLITE_FCNTL_MMAP_LIMIT, &mx);
}
#endif
}
/*
@@ -5042,7 +5054,7 @@ int sqlite3PagerSharedLock(Pager *pPager){
if( !pPager->tempFile && (
pPager->pBackup
|| sqlite3PcachePagecount(pPager->pPCache)>0
|| pPager->bUseFetch
|| USEFETCH(pPager)
)){
/* The shared-lock has just been acquired on the database file
** and there are already pages in the cache (from a previous
@@ -5085,7 +5097,7 @@ int sqlite3PagerSharedLock(Pager *pPager){
** In this case there may exist a Pager.pMap mapping that appears
** to be the right size but is not actually valid. Avoid this
** possibility by unmapping the db here. */
if( pPager->bUseFetch ){
if( USEFETCH(pPager) ){
sqlite3OsUnfetch(pPager->fd, 0, 0);
}
}
@@ -5199,7 +5211,7 @@ int sqlite3PagerAcquire(
** page 1 if there is no write-transaction open or the ACQUIRE_READONLY
** flag was specified by the caller. And so long as the db is not a
** temporary or in-memory database. */
const int bMmapOk = (pgno!=1 && pPager->bUseFetch
const int bMmapOk = (pgno!=1 && USEFETCH(pPager)
&& (pPager->eState==PAGER_READER || (flags & PAGER_ACQUIRE_READONLY))
);