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Reduce the amount of memory taken up by WAL mmaped regions under Windows.

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FossilOrigin-Name: f213e133f6e69b0edd73d96142014bdcab9dfe41
This commit is contained in:
shaneh
2010-09-03 04:29:30 +00:00
parent 9dd55f5187
commit 420398ce09
3 changed files with 45 additions and 22 deletions
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41
src/os_win.c
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@@ -1212,6 +1212,14 @@ static int winDeviceCharacteristics(sqlite3_file *id){
#ifndef SQLITE_OMIT_WAL
/*
** Windows will only let you create file view mappings
** on allocation size granularity boundaries.
** During sqlite3_os_init() we do a GetSystemInfo()
** to get the granularity size.
*/
SYSTEM_INFO winSysInfo;
/*
** Helper functions to obtain and relinquish the global mutex. The
** global mutex is used to protect the winLockInfo objects used by
@@ -1380,6 +1388,7 @@ static int winDelete(sqlite3_vfs *,const char*,int);
static void winShmPurge(sqlite3_vfs *pVfs, int deleteFlag){
winShmNode **pp;
winShmNode *p;
BOOL bRc;
assert( winShmMutexHeld() );
pp = &winShmNodeList;
while( (p = *pp)!=0 ){
@@ -1387,8 +1396,14 @@ static void winShmPurge(sqlite3_vfs *pVfs, int deleteFlag){
int i;
if( p->mutex ) sqlite3_mutex_free(p->mutex);
for(i=0; i<p->nRegion; i++){
UnmapViewOfFile(p->aRegion[i].pMap);
CloseHandle(p->aRegion[i].hMap);
bRc = UnmapViewOfFile(p->aRegion[i].pMap);
OSTRACE(("SHM-PURGE pid-%d unmap region=%d %s\n",
(int)GetCurrentProcessId(), i,
bRc ? "ok" : "failed"));
bRc = CloseHandle(p->aRegion[i].hMap);
OSTRACE(("SHM-PURGE pid-%d close region=%d %s\n",
(int)GetCurrentProcessId(), i,
bRc ? "ok" : "failed"));
}
if( p->hFile.h != INVALID_HANDLE_VALUE ){
SimulateIOErrorBenign(1);
@@ -1465,6 +1480,7 @@ static int winOpenSharedMemory(winFile *pDbFd){
rc = SQLITE_NOMEM;
goto shm_open_err;
}
rc = winOpen(pDbFd->pVfs,
pShmNode->zFilename, /* Name of the file (UTF-8) */
(sqlite3_file*)&pShmNode->hFile, /* File handle here */
@@ -1776,10 +1792,18 @@ static int winShmMap(
hMap = CreateFileMapping(pShmNode->hFile.h,
NULL, PAGE_READWRITE, 0, nByte, NULL
);
OSTRACE(("SHM-MAP pid-%d create region=%d nbyte=%d %s\n",
(int)GetCurrentProcessId(), pShmNode->nRegion, nByte,
hMap ? "ok" : "failed"));
if( hMap ){
int iOffset = pShmNode->nRegion*szRegion;
int iOffsetShift = iOffset % winSysInfo.dwAllocationGranularity;
pMap = MapViewOfFile(hMap, FILE_MAP_WRITE | FILE_MAP_READ,
0, 0, nByte
0, iOffset - iOffsetShift, szRegion + iOffsetShift
);
OSTRACE(("SHM-MAP pid-%d map region=%d offset=%d size=%d %s\n",
(int)GetCurrentProcessId(), pShmNode->nRegion, iOffset, szRegion,
pMap ? "ok" : "failed"));
}
if( !pMap ){
pShmNode->lastErrno = GetLastError();
@@ -1796,8 +1820,10 @@ static int winShmMap(
shmpage_out:
if( pShmNode->nRegion>iRegion ){
int iOffset = iRegion*szRegion;
int iOffsetShift = iOffset % winSysInfo.dwAllocationGranularity;
char *p = (char *)pShmNode->aRegion[iRegion].pMap;
*pp = (void *)&p[iRegion*szRegion];
*pp = (void *)&p[iOffsetShift];
}else{
*pp = 0;
}
@@ -2738,6 +2764,13 @@ int sqlite3_os_init(void){
winCurrentTimeInt64, /* xCurrentTimeInt64 */
};
#ifndef SQLITE_OMIT_WAL
/* get memory map allocation granularity */
memset(&winSysInfo, 0, sizeof(SYSTEM_INFO));
GetSystemInfo(&winSysInfo);
assert(winSysInfo.dwAllocationGranularity > 0);
#endif
sqlite3_vfs_register(&winVfs, 1);
return SQLITE_OK;
}