Add the SQLITE_FCNTL_SIZE_HINT operator to sqlite3_file_control() and use it

to give the VFS hints about the ultimate size of a database file when the
file is growing.

FossilOrigin-Name: 2b7e3b4a30d6a7c4a8a4b8e7dd2ed728b565c96d

1 files changed, 8 insertions, 0 deletions

diff --git a/src/pager.c b/src/pager.c
index 42403c997..43ac8eb32 100644
--- a/src/pager.c
+++ b/src/pager.c
@@ -3332,6 +3332,14 @@ static int pager_write_pagelist(PgHdr *pList){
     rc = pagerOpentemp(pPager, pPager->fd, pPager->vfsFlags);
   }
 
+  /* Before the first write, give the VFS a hint of what the final
+  ** file size will be.
+  */
+  if( pPager->dbSize > (pPager->dbOrigSize+1) && isOpen(pPager->fd) ){
+    sqlite3_int64 szFile = pPager->pageSize * (sqlite3_int64)pPager->dbSize;
+    sqlite3OsFileControl(pPager->fd, SQLITE_FCNTL_SIZE_HINT, &szFile);
+  }
+
   while( rc==SQLITE_OK && pList ){
     Pgno pgno = pList->pgno;