Add the SQLITE_FCNTL_RESET_CACHE verb. Use it to ensure that the page cache is purged before and after a the recovery extension is run.

FossilOrigin-Name: 6db0bc4bc0d272b610bef2aeeae43f539ed6e7cc0a9cc767d5af85ecb0019d5f

1 files changed, 5 insertions, 1 deletions

diff --git a/ext/recover/sqlite3recover.c b/ext/recover/sqlite3recover.c
index 30260f014..e62aba752 100644
--- a/ext/recover/sqlite3recover.c
+++ b/ext/recover/sqlite3recover.c
@@ -2017,6 +2017,7 @@ static void recoverFinalCleanup(sqlite3_recover *p){
   p->pTblList = 0;
   sqlite3_finalize(p->pGetPage);
   p->pGetPage = 0;
+  sqlite3_file_control(p->dbIn, p->zDb, SQLITE_FCNTL_RESET_CACHE, 0);
 
   {
 #ifndef NDEBUG
@@ -2315,6 +2316,7 @@ static int recoverVfsRead(sqlite3_file *pFd, void *aBuf, int nByte, i64 iOff){
       **
       **   + first freelist page (32-bits at offset 32)
       **   + size of freelist (32-bits at offset 36)
+      **   + the wal-mode flags (16-bits at offset 18)
       **
       ** We also try to preserve the auto-vacuum, incr-value, user-version
       ** and application-id fields - all 32 bit quantities at offsets 
@@ -2378,7 +2380,8 @@ static int recoverVfsRead(sqlite3_file *pFd, void *aBuf, int nByte, i64 iOff){
       if( p->pPage1Cache ){
         p->pPage1Disk = &p->pPage1Cache[nByte];
         memcpy(p->pPage1Disk, aBuf, nByte);
-
+        aHdr[18] = a[18];
+        aHdr[19] = a[19];
         recoverPutU32(&aHdr[28], dbsz);
         recoverPutU32(&aHdr[56], enc);
         recoverPutU16(&aHdr[105], pgsz-nReserve);
@@ -2574,6 +2577,7 @@ static void recoverStep(sqlite3_recover *p){
       recoverOpenOutput(p);
 
       /* Open transactions on both the input and output databases. */
+      sqlite3_file_control(p->dbIn, p->zDb, SQLITE_FCNTL_RESET_CACHE, 0);
       recoverExec(p, p->dbIn, "PRAGMA writable_schema = on");
       recoverExec(p, p->dbIn, "BEGIN");
       if( p->errCode==SQLITE_OK ) p->bCloseTransaction = 1;