From: dan <dan@noemail.net>
Date: Fri, 12 May 2017 18:52:27 +0000 (+0000)
Subject: Require exclusive access to the db to wrap the wal file. Have "PRAGMA
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=bf431367f3544b66b13ba8a329c6ef1dd8044ebd;p=thirdparty%2Fsqlite.git

Require exclusive access to the db to wrap the wal file. Have "PRAGMA
wal_checkpoint = restart" block for this.

FossilOrigin-Name: cbf44ed9758d577e1450b53e645b73c9ca1ee29d2354ce6375c234a41a063400
---

diff --git a/manifest b/manifest
index a23f43ff89..4a54d5acb2 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Fix\sa\sproblem\scausing\sa\slock\sto\sbe\sheld\spast\sthe\send\sof\sa\stransaction.\sUse\sa\nblocking\slock\sto\stake\sthe\sread-lock\son\spage\s1\staken\sby\sall\stransactions.
-D 2017-05-10T16:18:05.140
+C Require\sexclusive\saccess\sto\sthe\sdb\sto\swrap\sthe\swal\sfile.\sHave\s"PRAGMA\nwal_checkpoint\s=\srestart"\sblock\sfor\sthis.
+D 2017-05-12T18:52:27.743
 F Makefile.in 1cc758ce3374a32425e4d130c2fe7b026b20de5b8843243de75f087c0a2661fb
 F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434
 F Makefile.msc 6a8c838220f7c00820e1fc0ac1bccaaa8e5676067e1dbfa1bafa7a4ffecf8ae6
@@ -482,7 +482,7 @@ F src/vdbesort.c e72fe02a2121386ba767ede8942e9450878b8fc873abf3d1b6824485f092570
 F src/vdbetrace.c 41963d5376f0349842b5fc4aaaaacd7d9cdc0834
 F src/vtab.c 35b9bdc2b41de32a417141d12097bcc4e29a77ed7cdb8f836d1d2305d946b61b
 F src/vxworks.h d2988f4e5a61a4dfe82c6524dd3d6e4f2ce3cdb9
-F src/wal.c b78eab7bb45f6c5b59ad90b7825adb2fe10cb3bc73295d2fcdaa61859f078301
+F src/wal.c c2c7289acf4e7c8222d53c7f4ddc0553c60b130c08ce7e6ff3c54a079afb11eb
 F src/wal.h 739d92494eb18b6d8f3e353e66c10eb8f94534bafd336ece9f3f60235317ea08
 F src/walker.c b71a992b413b3a022572eccf29ef4b4890223791
 F src/where.c c6352f15be5031907c68bcbde96cad1a6da20e9f4051d10168a59235de9a8566
@@ -1115,7 +1115,7 @@ F test/server1.test 46803bd3fe8b99b30dbc5ff38ffc756f5c13a118
 F test/server2.test 11dda300ebef43b4abe0fdc086b6f51b964beddb529fb65bc1f026db5895c36e
 F test/server3.test c33343f2f6bc23f2b4e2f047c3d083579f0cfac2795e0f1eb226ab34758967c0
 F test/servercrash.test 816c132b26af008067cab2913783f67006d4003e3988f3f3ee1075742f6e0a6c
-F test/serverwal.test a162dd5105b0c1d6d68a12224aae06aba06812503396711fdc70f967b9f00f8d
+F test/serverwal.test 2d066ba70db35e28f0115a57385cf606513c56d6e2861119c2defb7471e4e2d9
 F test/session.test 78fa2365e93d3663a6e933f86e7afc395adf18be
 F test/shared.test 1da9dbad400cee0d93f252ccf76e1ae007a63746
 F test/shared2.test 03eb4a8d372e290107d34b6ce1809919a698e879
@@ -1584,7 +1584,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 4464ca1d686b5c457995cc885d4a8704e402ad387aa4cc37de199276b28cc08e
-R 8af7c0b56c931c6427bbb46d22a2354a
+P 2584df3d42ece69d37f31f3655cd0d4760914bea73d4f4ccb7f2a7aa47f80f49
+R 8621dc84bbe8eab1b9dea62b9019e55d
 U dan
-Z 9c853b21d10daf349150cf7187819c31
+Z ad37dc40e7be8af9dbc4865f3cd7c6dc
diff --git a/manifest.uuid b/manifest.uuid
index cf91b36b8c..6621b47df9 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-2584df3d42ece69d37f31f3655cd0d4760914bea73d4f4ccb7f2a7aa47f80f49
\ No newline at end of file
+cbf44ed9758d577e1450b53e645b73c9ca1ee29d2354ce6375c234a41a063400
\ No newline at end of file
diff --git a/src/wal.c b/src/wal.c
index 3a70b29946..6e5e512245 100644
--- a/src/wal.c
+++ b/src/wal.c
@@ -1909,6 +1909,9 @@ static int walCheckpoint(
           ** indicate that the log file contains zero valid frames.  */
           walRestartHdr(pWal, salt1);
           rc = sqlite3OsTruncate(pWal->pWalFd, 0);
+        }else if( walIsServer(pWal) ){
+          assert( eMode==SQLITE_CHECKPOINT_RESTART );
+          walRestartHdr(pWal, salt1);
         }
         walUnlockExclusive(pWal, WAL_READ_LOCK(1), WAL_NREADER-1);
       }
@@ -3126,7 +3129,7 @@ int sqlite3WalFrames(
   /* See if it is possible to write these frames into the start of the
   ** log file, instead of appending to it at pWal->hdr.mxFrame.
   */
-  if( SQLITE_OK!=(rc = walRestartLog(pWal)) ){
+  if( walIsServer(pWal)==0 && SQLITE_OK!=(rc = walRestartLog(pWal)) ){
     return rc;
   }
 
@@ -3379,7 +3382,13 @@ int sqlite3WalCheckpoint(
   */
   if( eMode!=SQLITE_CHECKPOINT_PASSIVE ){
     if( walIsServer(pWal) ){
-      rc = sqlite3ServerLock(pWal->pServer, 0, 1, 1);
+      if( eMode>=SQLITE_CHECKPOINT_RESTART ){
+        /* Exclusive lock on page 1. This is exclusive access to the db. */
+        rc = sqlite3ServerLock(pWal->pServer, 1, 1, 1);
+      }else{
+        /* Take the server write-lock ("page" 0) */
+        rc = sqlite3ServerLock(pWal->pServer, 0, 1, 1);
+      }
     }else{
       rc = walBusyLock(pWal, xBusy, pBusyArg, WAL_WRITE_LOCK, 1);
     }
@@ -3431,6 +3440,7 @@ int sqlite3WalCheckpoint(
   walUnlockExclusive(pWal, WAL_CKPT_LOCK, 1);
   pWal->ckptLock = 0;
   WALTRACE(("WAL%p: checkpoint %s\n", pWal, rc ? "failed" : "ok"));
+  if( walIsServer(pWal) ) sqlite3ServerEnd(pWal->pServer);
   return (rc==SQLITE_OK && eMode!=eMode2 ? SQLITE_BUSY : rc);
 }
 
diff --git a/test/serverwal.test b/test/serverwal.test
index abcd78b3be..2c442361c7 100644
--- a/test/serverwal.test
+++ b/test/serverwal.test
@@ -61,6 +61,7 @@ do_test 2.2 {
   execsql COMMIT db2
 } {}
 db close
+db2 close
 
 #-------------------------------------------------------------------------
 # That the wal file can be wrapped around.
@@ -79,7 +80,7 @@ do_execsql_test 3.0 {
 do_test 3.1 {
   set N [file size test.db-wal]
   execsql {
-    PRAGMA wal_checkpoint;
+    PRAGMA wal_checkpoint = restart;
     INSERT INTO ttt VALUES(11, 12);
     INSERT INTO ttt VALUES(13, 14);
   }
@@ -109,5 +110,29 @@ do_execsql_test 4.1 {
   PRAGMA integrity_check;
 } {ok ok}
 
+reset_db
+do_execsql_test 5.1 {
+  CREATE TABLE xyz(a);
+  PRAGMA journal_mode = wal;
+  INSERT INTO xyz VALUES(1);
+  INSERT INTO xyz VALUES(2);
+  INSERT INTO xyz VALUES(3);
+} {wal}
+
+breakpoint
+
+do_test 5.2 {
+  sqlite3 db2 test.db
+  execsql { SELECT * FROM xyz } db2
+} {1 2 3}
+
+do_execsql_test 5.3 {
+  PRAGMA wal_checkpoint = restart 
+} {0 0 0}
+
+do_test 5.4 {
+  execsql { SELECT * FROM xyz } db2
+} {1 2 3}
+
 finish_test