# 2018 July 4 # # The author disclaims copyright to this source code. In place of # a legal notice, here is a blessing: # # May you do good and not evil. # May you find forgiveness for yourself and forgive others. # May you share freely, never taking more than you give. # #*********************************************************************** # set testdir [file dirname $argv0] source $testdir/tester.tcl source $testdir/lock_common.tcl source $testdir/wal_common.tcl ifcapable !wal {finish_test ; return } set testprefix walprotocol2 #------------------------------------------------------------------------- # When recovering the contents of a WAL file, a process obtains the WRITER # lock, then locks all other bytes before commencing recovery. If it fails # to lock all other bytes (because some other process is holding a read # lock) it should retry up to 100 times. Then return SQLITE_PROTOCOL to the # caller. Test this (test case 1.3). # # Also test the effect of hitting an SQLITE_BUSY while attempting to obtain # the WRITER lock (should be the same). Test case 1.4. # do_execsql_test 1.0 { PRAGMA journal_mode = wal; CREATE TABLE x(y); INSERT INTO x VALUES('z'); } {wal} db close proc lock_callback {method filename handle lock} { # puts "$method $filename $handle $lock" } testvfs T T filter xShmLock T script lock_callback sqlite3 db test.db -vfs T sqlite3 db2 test.db -vfs T do_execsql_test 2.0 { SELECT * FROM x; } {z} do_execsql_test -db db2 2.1 { SELECT * FROM x; } {z} #--------------------------------------------------------------- # Attempt a "BEGIN EXCLUSIVE" using connection handle [db]. This # causes SQLite to open a read transaction, then a write transaction. # Rig the xShmLock() callback so that just before the EXCLUSIVE lock # for the write transaction is taken, connection [db2] jumps in and # modifies the database. This causes the "BEGIN EXCLUSIVE" to throw # an SQLITE_BUSY_SNAPSHOT error. # proc lock_callback {method filename handle lock} { if {$lock=="0 1 lock exclusive"} { proc lock_callback {method filename handle lock} {} db2 eval { INSERT INTO x VALUES('y') } } } do_catchsql_test 2.2 { BEGIN EXCLUSIVE; } {1 {database is locked}} do_test 2.3 { sqlite3_extended_errcode db } {SQLITE_BUSY} #--------------------------------------------------------------- # Same again, but with a busy-handler. This time, following the # SQLITE_BUSY_SNAPSHOT error the busy-handler is invoked and then the # whole thing retried from the beginning. This time it succeeds. # proc lock_callback {method filename handle lock} { if {$lock=="0 1 lock exclusive"} { proc lock_callback {method filename handle lock} {} db2 eval { INSERT INTO x VALUES('x') } } } db timeout 10 do_catchsql_test 2.4 { BEGIN EXCLUSIVE; } {0 {}} do_execsql_test 2.5 { SELECT * FROM x; COMMIT; } {z y x} finish_test