[sql] Patch SQLite to allow control of close-time WAL checkpoint.

third_party/sqlite/amalgamation/sqlite3.c

Index: third_party/sqlite/amalgamation/sqlite3.c
diff --git a/third_party/sqlite/amalgamation/sqlite3.c b/third_party/sqlite/amalgamation/sqlite3.c
index 97d1ab9912109aba2d8c6268f4967449c2b4b28c..316bf94dbb8cf6e3a3be7986038498ebd67fb6eb 100644
--- a/third_party/sqlite/amalgamation/sqlite3.c
+++ b/third_party/sqlite/amalgamation/sqlite3.c
@@ -2118,11 +2118,24 @@ struct sqlite3_mem_methods {
 ** following this call.  The second parameter may be a NULL pointer, in
 ** which case the trigger setting is not reported back. </dd>
 **
+** <dt>SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE</dt>
+** <dd> Usually, when a database in wal mode is closed or detached from a 
+** database handle, SQLite checks if this will mean that there are now no 
+** connections at all to the database. If so, it performs a checkpoint 
+** operation before closing the connection. This option may be used to
+** override this behaviour. The first parameter passed to this operation
+** is an integer - non-zero to disable checkpoints-on-close, or zero (the
+** default) to enable them. The second parameter is a pointer to an integer
+** into which is written 0 or 1 to indicate whether checkpoints-on-close
+** have been disabled - 0 if they are not disabled, 1 if they are.
+** </dd>
+**
 ** </dl>
 */
 #define SQLITE_DBCONFIG_LOOKASIDE       1001  /* void* int int */
 #define SQLITE_DBCONFIG_ENABLE_FKEY     1002  /* int int* */
 #define SQLITE_DBCONFIG_ENABLE_TRIGGER  1003  /* int int* */
+#define SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE      1006 /* int int* */
 
 
 /*
@@ -11170,7 +11183,7 @@ SQLITE_PRIVATE int sqlite3PagerOpen(
   int,
   void(*)(DbPage*)
 );
-SQLITE_PRIVATE int sqlite3PagerClose(Pager *pPager);
+SQLITE_PRIVATE int sqlite3PagerClose(Pager *pPager, sqlite3*);
 SQLITE_PRIVATE int sqlite3PagerReadFileheader(Pager*, int, unsigned char*);
 
 /* Functions used to configure a Pager object. */
@@ -12132,6 +12145,7 @@ struct sqlite3 {
 #define SQLITE_VdbeEQP        0x04000000  /* Debug EXPLAIN QUERY PLAN */
 #define SQLITE_Vacuum         0x08000000  /* Currently in a VACUUM */
 #define SQLITE_CellSizeCk     0x10000000  /* Check btree cell sizes on load */
+#define SQLITE_NoCkptOnClose  0x80000000  /* No checkpoint on close()/DETACH */
 
 
 /*
@@ -47488,7 +47502,7 @@ static void pagerFreeMapHdrs(Pager *pPager){
 ** a hot journal may be left in the filesystem but no error is returned
 ** to the caller.
 */
-SQLITE_PRIVATE int sqlite3PagerClose(Pager *pPager){
+SQLITE_PRIVATE int sqlite3PagerClose(Pager *pPager, sqlite3 *db){
   u8 *pTmp = (u8 *)pPager->pTmpSpace;
 
   assert( assert_pager_state(pPager) );
@@ -47498,7 +47512,9 @@ SQLITE_PRIVATE int sqlite3PagerClose(Pager *pPager){
   /* pPager->errCode = 0; */
   pPager->exclusiveMode = 0;
 #ifndef SQLITE_OMIT_WAL
-  sqlite3WalClose(pPager->pWal, pPager->ckptSyncFlags, pPager->pageSize, pTmp);
+  sqlite3WalClose(pPager->pWal, pPager->ckptSyncFlags, pPager->pageSize,
+                  (db && (db->flags & SQLITE_NoCkptOnClose) ? 0 : pTmp)
+  );
   pPager->pWal = 0;
 #endif
   pager_reset(pPager);
@@ -57623,7 +57639,7 @@ SQLITE_PRIVATE int sqlite3BtreeOpen(
 btree_open_out:
   if( rc!=SQLITE_OK ){
     if( pBt && pBt->pPager ){
-      sqlite3PagerClose(pBt->pPager);
+      sqlite3PagerClose(pBt->pPager, 0);
     }
     sqlite3_free(pBt);
     sqlite3_free(p);
@@ -57764,7 +57780,7 @@ SQLITE_PRIVATE int sqlite3BtreeClose(Btree *p){
     ** Clean out and delete the BtShared object.
     */
     assert( !pBt->pCursor );
-    sqlite3PagerClose(pBt->pPager);
+    sqlite3PagerClose(pBt->pPager, p->db);
     if( pBt->xFreeSchema && pBt->pSchema ){
       pBt->xFreeSchema(pBt->pSchema);
     }
@@ -132970,6 +132986,7 @@ SQLITE_API int SQLITE_CDECL sqlite3_db_config(sqlite3 *db, int op, ...){
       } aFlagOp[] = {
         { SQLITE_DBCONFIG_ENABLE_FKEY,    SQLITE_ForeignKeys    },
         { SQLITE_DBCONFIG_ENABLE_TRIGGER, SQLITE_EnableTrigger  },
+        { SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE, SQLITE_NoCkptOnClose  },
       };
       unsigned int i;
       rc = SQLITE_ERROR; /* IMP: R-42790-23372 */