Index: src/btree.c ================================================================== --- src/btree.c +++ src/btree.c @@ -3512,33 +3512,56 @@ ** ** Every cursor is a candidate to be tripped, including cursors ** that belong to other database connections that happen to be ** sharing the cache with pBtree. ** -** This routine gets called when a rollback occurs. The writeOnly -** flag is set to 1 if the transaction did not make any schema -** changes, in which case the read cursors can continue operating. -** If schema changes did occur in the transaction, then both read -** and write cursors must both be tripped. +** This routine gets called when a rollback occurs. If the writeOnly +** flag is true, then only write-cursors need be tripped - read-only +** cursors save their current positions so that they may continue +** following the rollback. Or, if writeOnly is false, all cursors are +** tripped. In general, writeOnly is false if the transaction being +** rolled back modified the database schema. In this case b-tree root +** pages may be moved or deleted from the database altogether, making +** it unsafe for read cursors to continue. +** +** If the writeOnly flag is true and an error is encountered while +** saving the current position of a read-only cursor, all cursors, +** including all read-cursors are tripped. +** +** SQLITE_OK is returned if successful, or if an error occurs while +** saving a cursor position, an SQLite error code. */ -void sqlite3BtreeTripAllCursors(Btree *pBtree, int errCode, int writeOnly){ +int sqlite3BtreeTripAllCursors(Btree *pBtree, int errCode, int writeOnly){ BtCursor *p; + int rc = SQLITE_OK; + assert( (writeOnly==0 || writeOnly==1) && BTCF_WriteFlag==1 ); - if( pBtree==0 ) return; - sqlite3BtreeEnter(pBtree); - for(p=pBtree->pBt->pCursor; p; p=p->pNext){ - int i; - if( writeOnly && (p->curFlags & BTCF_WriteFlag)==0 ) continue; - sqlite3BtreeClearCursor(p); - p->eState = CURSOR_FAULT; - p->skipNext = errCode; - for(i=0; i<=p->iPage; i++){ - releasePage(p->apPage[i]); - p->apPage[i] = 0; + if( pBtree ){ + sqlite3BtreeEnter(pBtree); + for(p=pBtree->pBt->pCursor; p; p=p->pNext){ + int i; + if( writeOnly && (p->curFlags & BTCF_WriteFlag)==0 ){ + if( p->eState==CURSOR_VALID ){ + int rc = saveCursorPosition(p); + if( rc!=SQLITE_OK ){ + (void)sqlite3BtreeTripAllCursors(pBtree, rc, 0); + break; + } + } + }else{ + sqlite3BtreeClearCursor(p); + p->eState = CURSOR_FAULT; + p->skipNext = errCode; + } + for(i=0; i<=p->iPage; i++){ + releasePage(p->apPage[i]); + p->apPage[i] = 0; + } } + sqlite3BtreeLeave(pBtree); } - sqlite3BtreeLeave(pBtree); + return rc; } /* ** Rollback the transaction in progress. ** @@ -3563,11 +3586,13 @@ if( rc ) writeOnly = 0; }else{ rc = SQLITE_OK; } if( tripCode ){ - sqlite3BtreeTripAllCursors(p, tripCode, writeOnly); + int rc2 = sqlite3BtreeTripAllCursors(p, tripCode, writeOnly); + assert( rc==SQLITE_OK || (writeOnly==0 && rc2==SQLITE_OK) ); + if( rc2!=SQLITE_OK ) rc = rc2; } btreeIntegrity(p); if( p->inTrans==TRANS_WRITE ){ int rc2; Index: src/btree.h ================================================================== --- src/btree.h +++ src/btree.h @@ -114,11 +114,11 @@ #define BTREE_BLOBKEY 2 /* Table has keys only - no data */ int sqlite3BtreeDropTable(Btree*, int, int*); int sqlite3BtreeClearTable(Btree*, int, int*); int sqlite3BtreeClearTableOfCursor(BtCursor*); -void sqlite3BtreeTripAllCursors(Btree*, int, int); +int sqlite3BtreeTripAllCursors(Btree*, int, int); void sqlite3BtreeGetMeta(Btree *pBtree, int idx, u32 *pValue); int sqlite3BtreeUpdateMeta(Btree*, int idx, u32 value); int sqlite3BtreeNewDb(Btree *p); Index: src/vdbe.c ================================================================== --- src/vdbe.c +++ src/vdbe.c @@ -2828,12 +2828,13 @@ int isSchemaChange; iSavepoint = db->nSavepoint - iSavepoint - 1; if( p1==SAVEPOINT_ROLLBACK ){ isSchemaChange = (db->flags & SQLITE_InternChanges)!=0; for(ii=0; iinDb; ii++){ - sqlite3BtreeTripAllCursors(db->aDb[ii].pBt, SQLITE_ABORT, + rc = sqlite3BtreeTripAllCursors(db->aDb[ii].pBt, SQLITE_ABORT, isSchemaChange==0); + if( rc!=SQLITE_OK ) goto abort_due_to_error; } }else{ isSchemaChange = 0; } for(ii=0; iinDb; ii++){ ADDED test/rollback2.test Index: test/rollback2.test ================================================================== --- test/rollback2.test +++ test/rollback2.test @@ -0,0 +1,74 @@ +# 2014 November 12 +# +# 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 +set ::testprefix rollback2 + +proc int2hex {i} { format %.2X $i } +db func int2hex int2hex + +do_execsql_test 1.0 { + SELECT int2hex(0), int2hex(100), int2hex(255) +} {00 64 FF} +do_execsql_test 1.1 { + CREATE TABLE t1(i, h); + CREATE INDEX i1 ON t1(h); + WITH data(a, b) AS ( + SELECT 1, int2hex(1) + UNION ALL + SELECT a+1, int2hex(a+1) FROM data WHERE a<40 + ) + INSERT INTO t1 SELECT * FROM data; +} {} + + +proc do_rollback_test {tn args} { + set A(-setup) "" + set A(-select) "" + set A(-result) "" + set A(-rollback) ROLLBACK + + array set O $args + foreach k [array names O] { + if {[info exists A($k)]==0} { error "unknown option: $k" } + set A($k) $O($k) + } + + for {set iRollback 0} 1 {incr iRollback} { + catch { db eval ROLLBACK } + set res [list] + db eval $A(-setup) + + set i 0 + db eval $A(-select) x { + if {$i==$iRollback} { db eval $A(-rollback) } + foreach k $x(*) { lappend res $x($k) } + incr i + } + + do_test $tn.$iRollback [list set {} $res] [list {*}$A(-result)] + if {$i < $iRollback} break + } +} + +do_rollback_test 2 -setup { + BEGIN; + DELETE FROM t1 WHERE (i%2)==1; +} -select { + SELECT i FROM t1 WHERE (i%2)==0 +} -result { + 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 +} + +finish_test +