Enable SELECT query planning tracing when compiled with

SQLITE_ENABLE_SELECTTRACE and either SQLITE_DEBUG or SQLITE_TEST.

FossilOrigin-Name: cbe0cf9ddf46f0a678c85d49bfa74e3b7712e1a1

manifest

@@ -1,5 +1,5 @@
-C Fix\sthe\susage\sof\sthe\s_GNU_SOURCE\sand\s_BSD_SOURCE\smacros\sin\sthe\smain\ninternal\sheader\sfile,\ssqliteInt.h.\s\sSet\sHAVE_STRCHRNUL\sto\s1\sby\sdefault\son\nLinux\sonly.
+C Enable\sSELECT\squery\splanning\stracing\swhen\scompiled\swith\s\nSQLITE_ENABLE_SELECTTRACE\sand\seither\sSQLITE_DEBUG\sor\sSQLITE_TEST.
-D 2014-09-20T00:35:05.099
+D 2014-09-20T18:18:33.584
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in cf57f673d77606ab0f2d9627ca52a9ba1464146a
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -216,7 +216,7 @@ F src/os_win.c 0a4042ef35f322e86fa01f6c8884c5e645b911e7
 F src/os_win.h 09e751b20bbc107ffbd46e13555dc73576d88e21
 F src/pager.c caab007743821d96752597c9cfd7351654697b06
 F src/pager.h ffd5607f7b3e4590b415b007a4382f693334d428
-F src/parse.y 22d6a074e5f5a7258947a1dc55a9bf946b765dd0
+F src/parse.y 1976d28f168c63c6c14008e9a896620e0c76c25e
 F src/pcache.c 4121a0571c18581ee9f82f086d5e2030051ebd6a
 F src/pcache.h 9b559127b83f84ff76d735c8262f04853be0c59a
 F src/pcache1.c dab8ab930d4a73b99768d881185994f34b80ecaa
@@ -226,12 +226,12 @@ F src/printf.c 3a47f526b173813d9a7f4e7044007771ba68cde1
 F src/random.c d10c1f85b6709ca97278428fd5db5bbb9c74eece
 F src/resolve.c a3466128b52a86c466e47ac1a19e2174f7b5cf89
 F src/rowset.c eccf6af6d620aaa4579bd3b72c1b6395d9e9fa1e
-F src/select.c 0cd6706fd52ae5db229e9041094db6ec27195335
+F src/select.c 4e00e042994ae38e60576921f78e45311eead49e
-F src/shell.c c00220cdd7f2027780bc25b78376c16dc24e4b7d
+F src/shell.c dad23987c34faddb061a339da3e92e05ccc6935e
 F src/sqlite.h.in 8b018219ce988913e5977d5de9ab4beb33be23b6
 F src/sqlite3.rc 992c9f5fb8285ae285d6be28240a7e8d3a7f2bad
 F src/sqlite3ext.h 17d487c3c91b0b8c584a32fbeb393f6f795eea7d
-F src/sqliteInt.h 6fd801cac974d310949ddefd6a6c6982c9778f3f
+F src/sqliteInt.h 59b0796cd2fa201510ae9850b3b407fa9f997512
 F src/sqliteLimit.h 164b0e6749d31e0daa1a4589a169d31c0dec7b3d
 F src/status.c 7ac05a5c7017d0b9f0b4bcd701228b784f987158
 F src/table.c 2e99ef7ef16187e17033d9398dc962ce22dab5cb
@@ -1198,8 +1198,7 @@ F tool/vdbe_profile.tcl 67746953071a9f8f2f668b73fe899074e2c6d8c1
 F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
 F tool/warnings.sh 0abfd78ceb09b7f7c27c688c8e3fe93268a13b32
 F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
-P 544664cadfb4e504bc0b321c865d1ecb8a831e20 0fac2c045f47c7735af4eb68ced81d8b43622a1f
+P 59e2c9df02d7e988c5ad44c560ead1e5288b12e7
-R 8acbfeff4e0806bab5948d89d293bcf4
+R e5319fc7a5c9cf5efe2dc73e6ab8c7e0
-T +closed 0fac2c045f47c7735af4eb68ced81d8b43622a1f
 U drh
-Z 03e6ed8cf11426837aa81912fc8917d5
+Z 7cccf9f838c01602cd52161c3ac81285

manifest.uuid

@@ -1 +1 @@
-59e2c9df02d7e988c5ad44c560ead1e5288b12e7
+cbe0cf9ddf46f0a678c85d49bfa74e3b7712e1a1

src/parse.y

@@ -459,9 +459,33 @@ multiselect_op(A) ::= UNION(OP).             {A = @OP;}
 multiselect_op(A) ::= UNION ALL.             {A = TK_ALL;}
 multiselect_op(A) ::= EXCEPT|INTERSECT(OP).  {A = @OP;}
 %endif SQLITE_OMIT_COMPOUND_SELECT
-oneselect(A) ::= SELECT distinct(D) selcollist(W) from(X) where_opt(Y)
+oneselect(A) ::= SELECT(S) distinct(D) selcollist(W) from(X) where_opt(Y)
                  groupby_opt(P) having_opt(Q) orderby_opt(Z) limit_opt(L). {
   A = sqlite3SelectNew(pParse,W,X,Y,P,Q,Z,D,L.pLimit,L.pOffset);
+#if SELECTTRACE_ENABLED
+  /* Populate the Select.zSelLabel[] string that is used to help with
+  ** query planner debugging, to differentiate between multiple Select
+  ** objects in a complex query.
+  **
+  ** If the SELECT keyword is immediately followed by a C-style comment
+  ** then extract the first few alphanumeric characters from within that
+  ** comment to be the zSelLabel value.  Otherwise, the label is #N where
+  ** is an integer that is incremented with each SELECT statement seen.
+  */
+  if( A!=0 ){
+    const char *z = S.z+6;
+    int i;
+    sqlite3_snprintf(sizeof(A->zSelLabel), A->zSelLabel, "#%d",
+                     ++pParse->nSelect);
+    while( z[0]==' ' ) z++;
+    if( z[0]=='/' && z[1]=='*' ){
+      z += 2;
+      while( z[0]==' ' ) z++;
+      for(i=0; sqlite3Isalnum(z[i]); i++){}
+      sqlite3_snprintf(sizeof(A->zSelLabel), A->zSelLabel, "%.*s", i, z);
+    }
+  }
+#endif /* SELECTRACE_ENABLED */
 }
 oneselect(A) ::= values(X).    {A = X;}
 

src/select.c

@@ -14,6 +14,17 @@
 */
 #include "sqliteInt.h"
 
+/*
+** Trace output macros
+*/
+#if SELECTTRACE_ENABLED
+/***/ int sqlite3SelectTrace = 0;
+# define SELECTTRACE(K,X)  if(sqlite3SelectTrace&(K)) sqlite3DebugPrintf X
+#else
+# define SELECTTRACE(K,X)
+#endif
+
+
 /*
 ** An instance of the following object is used to record information about
 ** how to process the DISTINCT keyword, to simplify passing that information
@@ -3355,6 +3366,8 @@ static int flattenSubquery(
   }
 
   /***** If we reach this point, flattening is permitted. *****/
+  SELECTTRACE(1, ("flatten %s (term %d) into %s\n",
+                   pSub->zSelLabel, iFrom, p->zSelLabel));
 
   /* Authorize the subquery */
   pParse->zAuthContext = pSubitem->zName;

src/shell.c

@@ -3101,6 +3101,15 @@ static int do_meta_command(char *zLine, ShellState *p){
     }
   }else
 
+
+#if defined(SQLITE_DEBUG) && defined(SQLITE_ENABLE_SELECTTRACE)
+  if( c=='s' && n==11 && strncmp(azArg[0], "selecttrace", n)==0 ){
+    extern int sqlite3SelectTrace;
+    sqlite3SelectTrace = nArg>=2 ? booleanValue(azArg[1]) : 0xff;
+  }else
+#endif
+
+
 #ifdef SQLITE_DEBUG
   /* Undocumented commands for internal testing.  Subject to change
   ** without notice. */

src/sqliteInt.h

@@ -706,6 +706,17 @@ extern const int sqlite3one;
 # undef SQLITE_ENABLE_STAT3_OR_STAT4
 #endif
 
+/*
+** SELECTTRACE_ENABLED will be either 1 or 0 depending on whether or not
+** the Select query generator tracing logic is turned on.
+*/
+#if defined(SQLITE_DEBUG) \
+    && (defined(SQLITE_TEST) || defined(SQLITE_ENABLE_SELECTTRACE))
+# define SELECTTRACE_ENABLED 1
+#else
+# define SELECTTRACE_ENABLED 0
+#endif
+
 /*
 ** An instance of the following structure is used to store the busy-handler
 ** callback for a given sqlite handle. 
@@ -2300,6 +2311,9 @@ struct Select {
   u8 op;                 /* One of: TK_UNION TK_ALL TK_INTERSECT TK_EXCEPT */
   u16 selFlags;          /* Various SF_* values */
   int iLimit, iOffset;   /* Memory registers holding LIMIT & OFFSET counters */
+#if SELECTTRACE_ENABLED
+  char zSelLabel[12];    /* Text in comment following SELECT keyword */
+#endif
   int addrOpenEphm[2];   /* OP_OpenEphem opcodes related to this select */
   u64 nSelectRow;        /* Estimated number of result rows */
   SrcList *pSrc;         /* The FROM clause */
@@ -2558,6 +2572,9 @@ struct Parse {
   int regRowid;        /* Register holding rowid of CREATE TABLE entry */
   int regRoot;         /* Register holding root page number for new objects */
   int nMaxArg;         /* Max args passed to user function by sub-program */
+#if SELECTTRACE_ENABLED
+  int nSelect;         /* Number of SELECT statements seen */
+#endif
 #ifndef SQLITE_OMIT_SHARED_CACHE
   int nTableLock;        /* Number of locks in aTableLock */
   TableLock *aTableLock; /* Required table locks for shared-cache mode */