Cherrypick [ec37ad6d08] into this branch. With this patch, if

SQLITE_SHARED_MAPPING is defined at build-time SQLite will use a single memory
mapping for multiple connections to the same database file within a single
process.

FossilOrigin-Name: c7a5880d6d898299b4c9414b7702cfa450aa5f7bf4ec8f417b94d2a7b6558264

diff --git a/manifest b/manifest
index b3429762a793a85d60f9aec74391767510ca4659..861009c90166bde561ec0eca11e3d9e6495d7a7a 100644 (file)
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Merge\slatest\strunk\schanges\sinto\sthis\sbranch.
-D 2017-09-22T10:49:03.297
+C Cherrypick\s[ec37ad6d08]\sinto\sthis\sbranch.\sWith\sthis\spatch,\sif\nSQLITE_SHARED_MAPPING\sis\sdefined\sat\sbuild-time\sSQLite\swill\suse\sa\ssingle\smemory\nmapping\sfor\smultiple\sconnections\sto\sthe\ssame\sdatabase\sfile\swithin\sa\ssingle\nprocess.
+D 2017-09-22T11:09:09.656
 F Makefile.in 4bc36d913c2e3e2d326d588d72f618ac9788b2fd4b7efda61102611a6495c3ff
 F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434
 F Makefile.msc 6033b51b6aea702ea059f6ab2d47b1d3cef648695f787247dd4fb395fe60673f
@@ -446,7 +446,7 @@ F src/os.c 93e0979b9b55df29c0c4923f73b48e9d3fe728f01dd8ed4f6a9d2f1d79779bc8
 F src/os.h 8e976e59eb4ca1c0fca6d35ee803e38951cb0343
 F src/os_common.h b2f4707a603e36811d9b1a13278bffd757857b85
 F src/os_setup.h 0dbaea40a7d36bf311613d31342e0b99e2536586
-F src/os_unix.c 3984fc069df59e26f000e30609611cecdb4e93293e6ee52313a473a7e874af1b
+F src/os_unix.c 1b2203f30ec4ecef66b0f9b714432edaffe0f89f189af7c6b1db3e2cb3a52d24
 F src/os_win.c 5c802f05e706c87c6e4cc6e9527f3364c7a7178458f93dffa5e19ac2e8eef9c1
 F src/os_win.h 7b073010f1451abe501be30d12f6bc599824944a
 F src/pager.c 84e90e0acee15766840f89b8be6f14322de16396d9229c494fec6c1cc03a69cf
@@ -1666,7 +1666,8 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P d53108e76307fb24ef1d8f75fe82c180f5588ad8e65eeceace92f4cecadfa452 0a12915b373cd0491a58d8f7a645711c620c70efced623e6b40aa01f23284157
-R 5b090dbbf85dc5792098185268ac7c8f
+P 307b802e8627c93a51e4c54851a4fab33db5061bb80e3d327ce53b127d6d511b
+Q +ec37ad6d08362f4c9faad9b629c0fa23f5864ff6ad7f4cbed93a25d5f7b815d8
+R a7069c27bdffb405c8574ad991612563
 U dan
-Z 51723e9e7fe6c543a37219e2d01ad740
+Z 9a1235c2d010c6dd3774c97b07deb6f2

diff --git a/manifest.uuid b/manifest.uuid
index f7b69a87af2b0e845f52e2f9ec1fc72bdece1576..da8f0bb88ea43cbf7cf5b31c6ecd0b58abb296d7 100644 (file)
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-307b802e8627c93a51e4c54851a4fab33db5061bb80e3d327ce53b127d6d511b
\ No newline at end of file
+c7a5880d6d898299b4c9414b7702cfa450aa5f7bf4ec8f417b94d2a7b6558264
\ No newline at end of file

diff --git a/src/os_unix.c b/src/os_unix.c
index 4445104dd62a8f29dcd6841dcd2c69d06d486c41..0e444e61f2096f39fc8249bbe49313b306248235 100644 (file)
--- a/src/os_unix.c
+++ b/src/os_unix.c
@@ -1115,6 +1115,10 @@ struct unixInodeInfo {
   sem_t *pSem;                    /* Named POSIX semaphore */
   char aSemName[MAX_PATHNAME+2];  /* Name of that semaphore */
 #endif
+#ifdef SQLITE_SHARED_MAPPING
+  sqlite3_int64 nSharedMapping;   /* Size of mapped region in bytes */
+  void *pSharedMapping;           /* Memory mapped region */
+#endif
 };
 
 /*
@@ -1249,6 +1253,13 @@ static void releaseInodeInfo(unixFile *pFile){
     pInode->nRef--;
     if( pInode->nRef==0 ){
       assert( pInode->pShmNode==0 );
+#ifdef SQLITE_SHARED_MAPPING
+      if( pInode->pSharedMapping ){
+        osMunmap(pInode->pSharedMapping, pInode->nSharedMapping);
+        pInode->pSharedMapping = 0;
+        pInode->nSharedMapping = 0;
+      }
+#endif
       closePendingFds(pFile);
       if( pInode->pPrev ){
         assert( pInode->pPrev->pNext==pInode );
@@ -2055,6 +2066,14 @@ static int nolockUnlock(sqlite3_file *NotUsed, int NotUsed2){
 ** Close the file.
 */
 static int nolockClose(sqlite3_file *id) {
+#ifdef SQLITE_SHARED_MAPPING
+  unixFile *pFd = (unixFile*)id;
+  if( pFd->pInode ){
+    unixEnterMutex();
+    releaseInodeInfo(pFd);
+    unixLeaveMutex();
+  }
+#endif
   return closeUnixFile(id);
 }
 
@@ -3874,6 +3893,9 @@ static int unixFileControl(sqlite3_file *id, int op, void *pArg){
       *(i64*)pArg = pFile->mmapSizeMax;
       if( newLimit>=0 && newLimit!=pFile->mmapSizeMax && pFile->nFetchOut==0 ){
         pFile->mmapSizeMax = newLimit;
+#ifdef SQLITE_SHARED_MAPPING
+        if( pFile->pInode==0 )
+#endif
         if( pFile->mmapSize>0 ){
           unixUnmapfile(pFile);
           rc = unixMapfile(pFile, -1);
@@ -4774,6 +4796,9 @@ static int unixShmUnmap(
 */
 static void unixUnmapfile(unixFile *pFd){
   assert( pFd->nFetchOut==0 );
+#ifdef SQLITE_SHARED_MAPPING
+  if( pFd->pInode ) return;
+#endif
   if( pFd->pMapRegion ){
     osMunmap(pFd->pMapRegion, pFd->mmapSizeActual);
     pFd->pMapRegion = 0;
@@ -4905,6 +4930,28 @@ static int unixMapfile(unixFile *pFd, i64 nMap){
     nMap = pFd->mmapSizeMax;
   }
 
+#ifdef SQLITE_SHARED_MAPPING
+  if( pFd->pInode ){
+    unixInodeInfo *pInode = pFd->pInode;
+    if( pFd->pMapRegion ) return SQLITE_OK;
+    unixEnterMutex();
+    if( pInode->pSharedMapping==0 ){
+      u8 *pNew = osMmap(0, nMap, PROT_READ, MAP_SHARED, pFd->h, 0);
+      if( pNew==MAP_FAILED ){
+        unixLogError(SQLITE_OK, "mmap", pFd->zPath);
+        pFd->mmapSizeMax = 0;
+      }else{
+        pInode->pSharedMapping = pNew;
+        pInode->nSharedMapping = nMap;
+      }
+    }
+    pFd->pMapRegion = pInode->pSharedMapping;
+    pFd->mmapSizeActual = pFd->mmapSize = pInode->nSharedMapping;
+    unixLeaveMutex();
+    return SQLITE_OK;
+  }
+#endif
+
   assert( nMap>0 || (pFd->mmapSize==0 && pFd->pMapRegion==0) );
   if( nMap!=pFd->mmapSize ){
     unixRemapfile(pFd, nMap);
@@ -5342,6 +5389,9 @@ static int fillInUnixFile(
   if( pLockingStyle == &posixIoMethods
 #if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
     || pLockingStyle == &nfsIoMethods
+#endif
+#ifdef SQLITE_SHARED_MAPPING
+    || pLockingStyle == &nolockIoMethods
 #endif
   ){
     unixEnterMutex();