Disable the multi-row one-pass DELETE optimization when the WHERE clause

contains a subquery.  Fix for ticket [dc6ebeda9396087].

FossilOrigin-Name: 3f221f592a9a19009076e568566c59801cd3fc32

manifest

@@ -1,5 +1,5 @@
-C Improvements\sto\sthe\sway\sthe\sLIKE\soptimization\sis\simplemented,\sresulting\sin\nslightly\ssmaller\sand\sfaster\scode\sthat\sis\seasier\sto\stest.
+C Disable\sthe\smulti-row\sone-pass\sDELETE\soptimization\swhen\sthe\sWHERE\sclause\ncontains\sa\ssubquery.\s\sFix\sfor\sticket\s[dc6ebeda9396087].
-D 2016-05-02T10:25:42.392
+D 2016-05-02T12:18:56.634
 F Makefile.in 9e816d0323e418fbc0f8b2c05fc14e0b3763d9e8
 F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434
 F Makefile.msc 71b8b16cf9393f68e2e2035486ca104872558836
@@ -330,7 +330,7 @@ F src/complete.c a3634ab1e687055cd002e11b8f43eb75c17da23e
 F src/ctime.c 60e135af364d777a9ab41c97e5e89cd224da6198
 F src/date.c 1cc9fb516ec9932c6fd4d2a0d2f8bc4480145c39
 F src/dbstat.c c845548d4346e606e2f2b7d2e714ace2b8a7dd1b
-F src/delete.c 78eb999114ec04fcf1b7d123ccedb4b5b734930e
+F src/delete.c 362f89f8e6783e672c4ab06b90fca0177f9a576d
 F src/expr.c 8796c0739b2ad091e6779253f62aad6e767e2be1
 F src/fault.c 160a0c015b6c2629d3899ed2daf63d75754a32bb
 F src/fkey.c 4c0bd09e602b8ae8d36d81e31e4872d0b53c87bb
@@ -617,7 +617,7 @@ F test/default.test 0cb49b1c315a0d81c81d775e407f66906a2a604d
 F test/delete.test e1bcdf8926234e27aac24b346ad83d3329ec8b6f
 F test/delete2.test 3a03f2cca1f9a67ec469915cb8babd6485db43fa
 F test/delete3.test 555e84a00a99230b7d049d477a324a631126a6ab
-F test/delete4.test 738044ee892ee0c84e0848e36ba92c55f907d52b
+F test/delete4.test 21d2113217eeaacac2d99defe14fe6611615ae86
 F test/descidx1.test 6d03b44c8538fe0eb4924e19fba10cdd8f3c9240
 F test/descidx2.test 9f1a0c83fd57f8667c82310ca21b30a350888b5d
 F test/descidx3.test 09ddbe3f5295f482d2f8b687cf6db8bad7acd9a2
@@ -1486,7 +1486,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 820c57bb24ad3d8663ca512e4022268b940bb2ee
+P 54c63b329288729031f45b7778752552cd90e226
-R c58e65d0f2e2d03ddd82d7f66bccab45
+R 31fbd50c446b686ccdad6a76f26cbea2
 U drh
-Z 38f3015d7db64980369a2f7c9273004f
+Z 89acbaae560b0638ea30c0a72d46ae74

manifest.uuid

@@ -1 +1 @@
-54c63b329288729031f45b7778752552cd90e226
+3f221f592a9a19009076e568566c59801cd3fc32

src/delete.c

@@ -239,11 +239,12 @@ void sqlite3DeleteFrom(
   int addrBypass = 0;    /* Address of jump over the delete logic */
   int addrLoop = 0;      /* Top of the delete loop */
   int addrEphOpen = 0;   /* Instruction to open the Ephemeral table */
+  int bComplex;          /* True if there are triggers or FKs or or
+                         ** subqueries in the WHERE clause */
  
 #ifndef SQLITE_OMIT_TRIGGER
   int isView;                  /* True if attempting to delete from a view */
   Trigger *pTrigger;           /* List of table triggers, if required */
-  int bComplex;                /* True if there are either triggers or FKs */
 #endif
 
   memset(&sContext, 0, sizeof(sContext));
@@ -271,7 +272,6 @@ void sqlite3DeleteFrom(
 #else
 # define pTrigger 0
 # define isView 0
-# define bComplex 0
 #endif
 #ifdef SQLITE_OMIT_VIEW
 # undef isView
@@ -374,6 +374,7 @@ void sqlite3DeleteFrom(
 #endif /* SQLITE_OMIT_TRUNCATE_OPTIMIZATION */
   {
     u16 wcf = WHERE_ONEPASS_DESIRED|WHERE_DUPLICATES_OK;
+    if( pWhere && ExprHasProperty(pWhere, EP_Subquery) ) bComplex = 1;
     wcf |= (bComplex ? 0 : WHERE_ONEPASS_MULTIROW);
     if( HasRowid(pTab) ){
       /* For a rowid table, initialize the RowSet to an empty set */

test/delete4.test

@@ -161,4 +161,27 @@ do_execsql_test 5.0 {
   SELECT a FROM t1 WHERE b=2;
 } {}
 
+# 2016-05-02
+# Ticket https://www.sqlite.org/src/tktview/dc6ebeda93960877
+# A subquery in the WHERE clause of a one-pass DELETE can cause an
+# incorrect answer.
+#
+db close
+forcedelete test.db
+sqlite3 db test.db
+do_execsql_test 6.0 {
+  CREATE TABLE t2(x INT);
+  INSERT INTO t2(x) VALUES(1),(2),(3),(4),(5);
+  DELETE FROM t2 WHERE EXISTS(SELECT 1 FROM t2 AS v WHERE v.x=t2.x-1);
+  SELECT x FROM t2;
+} {1}
+do_execsql_test 6.1 {
+  DROP TABLE IF EXISTS t2;
+  CREATE TABLE t2(x INT);
+  INSERT INTO t2(x) VALUES(1),(2),(3),(4),(5);
+  DELETE FROM t2 WHERE EXISTS(SELECT 1 FROM t2 AS v WHERE v.x=t2.x+1);
+  SELECT x FROM t2;
+} {5}
+
+
 finish_test