From: drh <drh@noemail.net>
Date: Mon, 11 Jul 2011 18:17:56 +0000 (+0000)
Subject: Change the windows backend to retry read and write requests if the encounter
X-Git-Tag: version-3.7.8~38^2~18
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=5d9ef0a612105c623790418d46967b420fc530ad;p=thirdparty%2Fsqlite.git

Change the windows backend to retry read and write requests if the encounter
ERROR_LOCK_VIOLATION and ERROR_SHARING_VIOLATION errors - which we think
sometimes happens due to agressive anti-virus software.

FossilOrigin-Name: c20aca06610407c197ea50ea77c2591aacf2252a
---

diff --git a/manifest b/manifest
index 4f1bbb1b0b..bf84f0f2ec 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Fix\sharmless\scompiler\swarnings\son\sunix.
-D 2011-07-09T16:17:18.236
+C Change\sthe\swindows\sbackend\sto\sretry\sread\sand\swrite\srequests\sif\sthe\sencounter\nERROR_LOCK_VIOLATION\sand\sERROR_SHARING_VIOLATION\serrors\s-\swhich\swe\sthink\nsometimes\shappens\sdue\sto\sagressive\santi-virus\ssoftware.
+D 2011-07-11T18:17:56.144
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in c1d7a7f4fd8da6b1815032efca950e3d5125407e
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -166,7 +166,7 @@ F src/os.h 9dbed8c2b9c1f2f2ebabc09e49829d4777c26bf9
 F src/os_common.h a8f95b81eca8a1ab8593d23e94f8a35f35d4078f
 F src/os_os2.c 4a75888ba3dfc820ad5e8177025972d74d7f2440
 F src/os_unix.c d3e7b17100704ee0fe2ef71a98c478b947480f4d
-F src/os_win.c eafcd6b91cf204a7ef29ac1ef2a1b7132e132e58
+F src/os_win.c 6ba8a531bdc739b23143e8f1d26222ead4d0bdb0
 F src/pager.c 120550e7ef01dafaa2cbb4a0528c0d87c8f12b41
 F src/pager.h 3f8c783de1d4706b40b1ac15b64f5f896bcc78d1
 F src/parse.y 12b7ebd61ea54f0e1b1083ff69cc2c8ce9353d58
@@ -951,7 +951,7 @@ F tool/symbols.sh caaf6ccc7300fd43353318b44524853e222557d5
 F tool/tostr.awk 11760e1b94a5d3dcd42378f3cc18544c06cfa576
 F tool/vdbe-compress.tcl d70ea6d8a19e3571d7ab8c9b75cba86d1173ff0f
 F tool/warnings.sh 2ebae31e1eb352696f3c2f7706a34c084b28c262
-P 418a4da2a96cf33055f18c9a667754fad2111cf3
-R bd1403a9e638958833ef8e7e7178479a
+P 90b1aea17400bbda5ebc8ae4eb4e12127519e42e
+R 349c7f009f94630db798c4428c847d95
 U drh
-Z 18ede22d9ea411d29db6ab17e40995c3
+Z 6ec74c1e47a6a671533b542ae146a0f8
diff --git a/manifest.uuid b/manifest.uuid
index 0650cd683d..2020e584ff 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-90b1aea17400bbda5ebc8ae4eb4e12127519e42e
\ No newline at end of file
+c20aca06610407c197ea50ea77c2591aacf2252a
\ No newline at end of file
diff --git a/src/os_win.c b/src/os_win.c
index bd0f2f216a..59baeebb5f 100644
--- a/src/os_win.c
+++ b/src/os_win.c
@@ -402,6 +402,33 @@ static int winLogErrorAtLine(
   return errcode;
 }
 
+/*
+** The number of times that a ReadFile() or WriteFile() will be retried
+** following a locking error.
+*/
+#ifndef SQLITE_WIN32_IOERR_RETRY
+# define SQLITE_WIN32_IOERR_RETRY 5
+#endif
+
+/*
+** If a ReadFile() or WriteFile() error occurs, invoke this routine
+** to see if it should be retried.  Return TRUE to retry.  Return FALSE
+** to give up with an error.
+*/
+static int retryIoerr(int *pnRetry){
+  DWORD e;
+  if( *pnRetry>=SQLITE_WIN32_IOERR_RETRY ){
+    return 0;
+  }
+  e = GetLastError();
+  if( e==ERROR_LOCK_VIOLATION || e==ERROR_SHARING_VIOLATION ){
+    Sleep(50 + 50*(*pnRetry));
+    ++*pnRetry;
+    return 1;
+  }
+  return 0;
+}
+
 #if SQLITE_OS_WINCE
 /*************************************************************************
 ** This section contains code for WinCE only.
@@ -820,6 +847,7 @@ static int winRead(
 ){
   winFile *pFile = (winFile*)id;  /* file handle */
   DWORD nRead;                    /* Number of bytes actually read from file */
+  int nRetry = 0;                 /* Number of retrys */
 
   assert( id!=0 );
   SimulateIOError(return SQLITE_IOERR_READ);
@@ -828,7 +856,8 @@ static int winRead(
   if( seekWinFile(pFile, offset) ){
     return SQLITE_FULL;
   }
-  if( !ReadFile(pFile->h, pBuf, amt, &nRead, 0) ){
+  while( !ReadFile(pFile->h, pBuf, amt, &nRead, 0) ){
+    if( retryIoerr(&nRetry) ) continue;
     pFile->lastErrno = GetLastError();
     return winLogError(SQLITE_IOERR_READ, "winRead", pFile->zPath);
   }
@@ -866,8 +895,14 @@ static int winWrite(
     u8 *aRem = (u8 *)pBuf;        /* Data yet to be written */
     int nRem = amt;               /* Number of bytes yet to be written */
     DWORD nWrite;                 /* Bytes written by each WriteFile() call */
+    int nRetry = 0;               /* Number of retries */
 
-    while( nRem>0 && WriteFile(pFile->h, aRem, nRem, &nWrite, 0) && nWrite>0 ){
+    while( nRem>0 ){
+      if( !WriteFile(pFile->h, aRem, nRem, &nWrite, 0) ){
+        if( retryIoerr(&nRetry) ) continue;
+        break;
+      }
+      if( nWrite<=0 ) break;
       aRem += nWrite;
       nRem -= nWrite;
     }