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

third_party/sqlite/patches/0015-backport-Config-database-to-not-checkpoint-WAL-on-cl.patch

+From e5ba7652d3d8a1769955a579d84edbe5595d5e2b Mon Sep 17 00:00:00 2001
+From: Scott Hess <shess@chromium.org>
+Date: Fri, 16 Dec 2016 15:25:50 -0800
+Subject: [PATCH 15/15] [backport] Config database to not checkpoint WAL on
+ close.
+
+SQLite check-in https://www.sqlite.org/src/info/6d142025c74f66f2
+[With mods through pending 3.16.0.]
+
+"Add the SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE sqlite3_dbconfig() option -
+for disabling SQLite's default checkpoint-on-close behaviour."
+
+BUG=675264
+---
+ third_party/sqlite/src/src/btree.c     |  4 ++--
+ third_party/sqlite/src/src/main.c      |  1 +
+ third_party/sqlite/src/src/pager.c     |  6 ++++--
+ third_party/sqlite/src/src/pager.h     |  2 +-
+ third_party/sqlite/src/src/sqlite.h.in | 13 +++++++++++++
+ third_party/sqlite/src/src/sqliteInt.h |  1 +
+ 6 files changed, 22 insertions(+), 5 deletions(-)
+
+diff --git a/third_party/sqlite/src/src/btree.c b/third_party/sqlite/src/src/btree.c
+index f5feff8a..f987388 100644
+--- a/third_party/sqlite/src/src/btree.c
++++ b/third_party/sqlite/src/src/btree.c
+@@ -2390,7 +2390,7 @@ 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);
+@@ -2531,7 +2531,7 @@ 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);
+     }
+diff --git a/third_party/sqlite/src/src/main.c b/third_party/sqlite/src/src/main.c
+index 301808c..78181cd 100644
+--- a/third_party/sqlite/src/src/main.c
++++ b/third_party/sqlite/src/src/main.c
+@@ -799,6 +799,7 @@ int 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 */
+diff --git a/third_party/sqlite/src/src/pager.c b/third_party/sqlite/src/src/pager.c
+index 74c76f37..9201555 100644
+--- a/third_party/sqlite/src/src/pager.c
++++ b/third_party/sqlite/src/src/pager.c
+@@ -3991,7 +3991,7 @@ static void pagerFreeMapHdrs(Pager *pPager){
+ ** a hot journal may be left in the filesystem but no error is returned
+ ** to the caller.
+ */
+-int sqlite3PagerClose(Pager *pPager){
++int sqlite3PagerClose(Pager *pPager, sqlite3 *db){
+   u8 *pTmp = (u8 *)pPager->pTmpSpace;
+ 
+   assert( assert_pager_state(pPager) );
+@@ -4001,7 +4001,9 @@ 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);
+diff --git a/third_party/sqlite/src/src/pager.h b/third_party/sqlite/src/src/pager.h
+index 3552a87..1f5a584 100644
+--- a/third_party/sqlite/src/src/pager.h
++++ b/third_party/sqlite/src/src/pager.h
+@@ -112,7 +112,7 @@ int sqlite3PagerOpen(
+   int,
+   void(*)(DbPage*)
+ );
+-int sqlite3PagerClose(Pager *pPager);
++int sqlite3PagerClose(Pager *pPager, sqlite3*);
+ int sqlite3PagerReadFileheader(Pager*, int, unsigned char*);
+ 
+ /* Functions used to configure a Pager object. */
+diff --git a/third_party/sqlite/src/src/sqlite.h.in b/third_party/sqlite/src/src/sqlite.h.in
+index e5673fd..33334d3 100644
+--- a/third_party/sqlite/src/src/sqlite.h.in
++++ b/third_party/sqlite/src/src/sqlite.h.in
+@@ -1904,11 +1904,24 @@ 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* */
+ 
+ 
+ /*
+diff --git a/third_party/sqlite/src/src/sqliteInt.h b/third_party/sqlite/src/src/sqliteInt.h
+index 745b910..3b8b7d0 100644
+--- a/third_party/sqlite/src/src/sqliteInt.h
++++ b/third_party/sqlite/src/src/sqliteInt.h
+@@ -1305,6 +1305,7 @@ 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 */
+ 
+ 
+ /*
+-- 
+2.8.2
+