In wal mode, if a "BEGIN EXCLUSIVE" command (or any other command that

upgrades from no transaction directly to a write transaction) hits an
SQLITE_BUSY_SNAPSHOT error, change the error code to SQLITE_BUSY to indicate
to the caller that the condition may be transient.

FossilOrigin-Name: 221ff63e7902226ebf728bb7442727420636831163708f360724506ce9487ab6

diff --git a/manifest b/manifest
index 2357a1bfd45638db86fadd3a4c29a9f9847674f0..04e6ce195ecbc7164ac6ec991fcffb2beb492082 100644 (file)
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Test\sthat\sa\srace\scondition\scan\scause\sa\s"BEGIN\sEXCLUSIVE"\sto\sreturn\nSQLITE_BUSY_SNAPSHOT\sin\swal\smode.
-D 2018-07-03T20:17:27.649
+C In\swal\smode,\sif\sa\s"BEGIN\sEXCLUSIVE"\scommand\s(or\sany\sother\scommand\sthat\nupgrades\sfrom\sno\stransaction\sdirectly\sto\sa\swrite\stransaction)\shits\san\nSQLITE_BUSY_SNAPSHOT\serror,\schange\sthe\serror\scode\sto\sSQLITE_BUSY\sto\sindicate\nto\sthe\scaller\sthat\sthe\scondition\smay\sbe\stransient.
+D 2018-07-05T15:46:55.944
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F Makefile.in 0a3a6c81e6fcb969ff9106e882f0a08547014ba463cb6beca4c4efaecc924ee6
@@ -436,7 +436,7 @@ F src/auth.c a38f3c63c974787ecf75e3213f8cac6568b9a7af7591fb0372ec0517dd16dca8
 F src/backup.c 78d3cecfbe28230a3a9a1793e2ead609f469be43e8f486ca996006be551857ab
 F src/bitvec.c 17ea48eff8ba979f1f5b04cc484c7bb2be632f33
 F src/btmutex.c 8acc2f464ee76324bf13310df5692a262b801808984c1b79defb2503bbafadb6
-F src/btree.c bb23e5470ec0c9b9ae8e17c86cb686bc4112642d8f457bd42b3b3727d5ef78be
+F src/btree.c c2b55e3a31ad28c380e71053210fb3b28cc9c8d80b1a0aa2cb8566594f01e154
 F src/btree.h febb2e817be499570b7a2e32a9bbb4b607a9234f6b84bb9ae84916d4806e96f2
 F src/btreeInt.h 620ab4c7235f43572cf3ac2ac8723cbdf68073be4d29da24897c7b77dda5fd96
 F src/build.c 3b3bfa88800739e1f11313dcecfba5ef8e4757b6c929cdf7de9fcfc01002b81f
@@ -1583,7 +1583,7 @@ F test/walnoshm.test 84ca10c544632a756467336b7c3b864d493ee496
 F test/waloverwrite.test dad2f26567f1b45174e54fbf9a8dc1cb876a7f03
 F test/walpersist.test 8c6b7e3ec1ba91b5e4dc4e0921d6d3f87cd356a6
 F test/walprotocol.test a112aba0b79e3adeaa485fed09484b32c654e97df58e454aa8489ac2cd57bf84
-F test/walprotocol2.test ad92f036102f722b2d7f7ca7c1faf72d75f501a50c80a92d7fd87f8b1da6608c
+F test/walprotocol2.test 7d3b6b4bf0b12f8007121b1e6ef714bc99101fb3b48e46371df1db868eebc131
 F test/walro.test cb438d05ba0d191f10b688e39c4f0cd5b71569a1d1f4440e5bdf3c6880e08c20
 F test/walro2.test 0e79dd15cbdb4f482c01ea248373669c732414a726b357d04846a816afafb768
 F test/walrofault.test c70cb6e308c443867701856cce92ad8288cd99488fa52afab77cca6cfd51af68
@@ -1745,7 +1745,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P b6563647382634588ebe5c6a3c35c65a321dc1b3732c809d48ce46759b9dd80f
-R 85d71bbec8ad4dcf2f8e9507c907b291
+P 5a12db75d1da65daa92413a6b5892309e9d9479bb3610764e1015abe5bf28dbe
+R 00aacb5685c6162d17656913a07b3ca6
 U dan
-Z 38cb85199c9d8fc14bf46fba2bfb3f49
+Z 4f4ad7f92fd320b45a2f26133826954c

diff --git a/manifest.uuid b/manifest.uuid
index e6f611aeb3068299f474cc80de0323a8778727e4..b85851f8a95393d9568ac7f49e8f2964a62cfa6b 100644 (file)
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-5a12db75d1da65daa92413a6b5892309e9d9479bb3610764e1015abe5bf28dbe
\ No newline at end of file
+221ff63e7902226ebf728bb7442727420636831163708f360724506ce9487ab6
\ No newline at end of file

diff --git a/src/btree.c b/src/btree.c
index d2c580d11d470a70099765bc9a17eaadc578f312..cb1044155deb6ebbdb96b104e5742995e331275d 100644 (file)
--- a/src/btree.c
+++ b/src/btree.c
@@ -3424,6 +3424,14 @@ int sqlite3BtreeBeginTrans(Btree *p, int wrflag, int *pSchemaVersion){
         }
       }
     }
+  }else if( rc==SQLITE_BUSY_SNAPSHOT && pBt->inTransaction==TRANS_NONE ){
+    /* Even if there was no transaction opened when this function was
+    ** called, a race condition may cause an SQLITE_BUSY_SNAPSHOT error
+    ** in wal mode (since the code above opens a read-transaction and then
+    ** upgrades it to a write-transaction - it does not take the write lock
+    ** atomically). In this case change the error code to SQLITE_BUSY.  */
+    assert( wrFlag );
+    rc = SQLITE_BUSY;
   }
 
 

diff --git a/test/walprotocol2.test b/test/walprotocol2.test
index ea1c9a2f7d3fccabeffb68168efe620914e25abd..0792c9aae00501fb8e70c274a5563f7fe36ef751 100644 (file)
--- a/test/walprotocol2.test
+++ b/test/walprotocol2.test
@@ -72,7 +72,7 @@ do_catchsql_test 2.2 {
 } {1 {database is locked}}
 do_test 2.3 {
   sqlite3_extended_errcode db
-} {SQLITE_BUSY_SNAPSHOT}
+} {SQLITE_BUSY}
 
 #---------------------------------------------------------------
 # Same again, but with a busy-handler. This time, following the