Optimize the obscure case of running a checkpoint against a very large wal

file for which a large percentage of the frames have already been checkpointed.

FossilOrigin-Name: 0f5057dffa9be1bccab04894709d25bf1f066c4b1aef50d67ee635d46d300a4d

diff --git a/manifest b/manifest
index 1072fdeb6d18dafdc0183bd7f7f5491ba7ff855f..ae33a02d90cabf8f4d7dfc4920653a1807852c28 100644 (file)
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Typo\sfixes\sin\scomments.\s\sNo\schanges\sto\scode.
-D 2018-03-01T18:09:02.014
+C Optimize\sthe\sobscure\scase\sof\srunning\sa\scheckpoint\sagainst\sa\svery\slarge\swal\nfile\sfor\swhich\sa\slarge\spercentage\sof\sthe\sframes\shave\salready\sbeen\scheckpointed.
+D 2018-03-02T15:42:20.479
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F Makefile.in a2d2fb8d17c39ab5ec52beb27850b903949080848236923f436156b72a958737
@@ -568,7 +568,7 @@ F src/vdbesort.c 731a09e5cb9e96b70c394c1b7cf3860fbe84acca7682e178615eb941a3a0ef2
 F src/vdbetrace.c 48e11ebe040c6b41d146abed2602e3d00d621d7ebe4eb29b0a0f1617fd3c2f6c
 F src/vtab.c 0e4885495172e1bdf54b12cce23b395ac74ef5729031f15e1bc1e3e6b360ed1a
 F src/vxworks.h d2988f4e5a61a4dfe82c6524dd3d6e4f2ce3cdb9
-F src/wal.c 0ba9af2589b67c4bc60c773c7d2080491099037af21e73545f932bb29bf70b65
+F src/wal.c 6390a0f2779f0e3a8bfb47161575306f3078aed982334ea460506a4bdb168448
 F src/wal.h 8de5d2d3de0956d6f6cb48c83a4012d5f227b8fe940f3a349a4b7e85ebcb492a
 F src/walker.c da987a20d40145c0a03c07d8fefcb2ed363becc7680d0500d9c79915591f5b1f
 F src/where.c 7cae47e813393d70c6d327fdf000fcb30f76b1b0b5a5b52ff6402e0c658de32c
@@ -1708,7 +1708,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 2c01c72e357296d761493aac47329f15d87afcada2b39606fc018af0e0011bb5
-R 74d9f04f790ae61bbdb4bfdda923d919
-U mistachkin
-Z 6963c71440aaaba3f2df4c41ff5161b5
+P 1293d4f64f322ee57510bdff497c54e0be2c9205217e1fd96887bba1f36bec40
+R 42a85dafbb1d61300db520734eab6ba4
+U dan
+Z fabb1aba79ebdc43ca9f460d856c2385

diff --git a/manifest.uuid b/manifest.uuid
index 168b5b04bff95ba9792b52ff82d02ca40ea79cce..1be68720ef4ce7def4fb2e4324771348e04ec0dc 100644 (file)
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-1293d4f64f322ee57510bdff497c54e0be2c9205217e1fd96887bba1f36bec40
\ No newline at end of file
+0f5057dffa9be1bccab04894709d25bf1f066c4b1aef50d67ee635d46d300a4d
\ No newline at end of file

diff --git a/src/wal.c b/src/wal.c
index d56946e309cdac591c5c06c21b6d39330259c1de..fdcaa8057baa2d26c8cbce5d99fa872b98b501cd 100644 (file)
--- a/src/wal.c
+++ b/src/wal.c
@@ -1585,8 +1585,9 @@ static void walIteratorFree(WalIterator *p){
 
 /*
 ** Construct a WalInterator object that can be used to loop over all 
-** pages in the WAL in ascending order. The caller must hold the checkpoint
-** lock.
+** pages in the WAL following frame nBackfill in ascending order. Frames
+** nBackfill or earlier may be included - excluding them is an optimization
+** only. The caller must hold the checkpoint lock.
 **
 ** On success, make *pp point to the newly allocated WalInterator object
 ** return SQLITE_OK. Otherwise, return an error code. If this routine
@@ -1595,7 +1596,7 @@ static void walIteratorFree(WalIterator *p){
 ** The calling routine should invoke walIteratorFree() to destroy the
 ** WalIterator object when it has finished with it.
 */
-static int walIteratorInit(Wal *pWal, WalIterator **pp){
+static int walIteratorInit(Wal *pWal, u32 nBackfill, WalIterator **pp){
   WalIterator *p;                 /* Return value */
   int nSegment;                   /* Number of segments to merge */
   u32 iLast;                      /* Last frame in log */
@@ -1632,7 +1633,7 @@ static int walIteratorInit(Wal *pWal, WalIterator **pp){
     rc = SQLITE_NOMEM_BKPT;
   }
 
-  for(i=0; rc==SQLITE_OK && i<nSegment; i++){
+  for(i=walFramePage(nBackfill+1); rc==SQLITE_OK && i<nSegment; i++){
     volatile ht_slot *aHash;
     u32 iZero;
     volatile u32 *aPgno;
@@ -1789,7 +1790,7 @@ static int walCheckpoint(
   if( pInfo->nBackfill<pWal->hdr.mxFrame ){
 
     /* Allocate the iterator */
-    rc = walIteratorInit(pWal, &pIter);
+    rc = walIteratorInit(pWal, pInfo->nBackfill, &pIter);
     if( rc!=SQLITE_OK ){
       return rc;
     }