Add new test file analyzeG.test, containing a test for the change on this branch.

FossilOrigin-Name: 243ab1852a2291595527ea1f26e78ad83eda285ae28f876bc1c703677f495cfa

manifest

@@ -1,5 +1,5 @@
-C When\sstat4\sinformation\sis\savailable,\stry\sto\suse\sit\sto\simprove\sthe\struth\nprobability\sof\sWHERE\sclause\sterms\sthat\sdo\snot\sparticipate\sin\sthe\sindex.
+C Add\snew\stest\sfile\sanalyzeG.test,\scontaining\sa\stest\sfor\sthe\schange\son\sthis\sbranch.
-D 2020-02-22T16:58:49.287
+D 2020-02-22T17:32:00.691
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -655,6 +655,7 @@ F test/analyzeC.test 489fe2ea3be3f17548e8dd895f1b41c9669b52de1b0861f5bffe6eec46e
 F test/analyzeD.test e50cd0b3e6063216cc0c88a1776e8645dc0bd65a6bb275769cbee33b7fd8d90c
 F test/analyzeE.test 8684e8ac5722fb97c251887ad97e5d496a98af1d
 F test/analyzeF.test 9e1a0537949eb5483642b1140a5c39e5b4025939024b935398471fa552f4dabb
+F test/analyzeG.test c42be77a06331f8677c94b44ba35e170f0771a07d869dffb6b0d78f18b562747
 F test/analyzer1.test 459fa02c445ddbf0101a3bad47b34290a35f2e49
 F test/async.test 1d0e056ba1bb9729283a0f22718d3a25e82c277b
 F test/async2.test c0a9bd20816d7d6a2ceca7b8c03d3d69c28ffb8b
@@ -1858,10 +1859,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P f02030b3403d67734bba471a91ad5bfdb03ddf6fdc3ef14808a04495e43b0470
+P 1babd6ec5d60e2c34aa1c0285ead768a88004218468e97262411973fe3487022
-R 0b7e29ed07d82aa79f09869cc21d3459
+R 2b88c80f8c57b2c7447cf9a6931d1437
-T *branch * stat4-truthprob
+U dan
-T *sym-stat4-truthprob *
+Z e854d74d6063f88b5d388938dfbba4ed
-T -sym-trunk *
-U drh
-Z b67db2665ec4d9de443f342c9e446178

manifest.uuid

@@ -1 +1 @@
-1babd6ec5d60e2c34aa1c0285ead768a88004218468e97262411973fe3487022
+243ab1852a2291595527ea1f26e78ad83eda285ae28f876bc1c703677f495cfa

test/analyzeG.test

@@ -0,0 +1,85 @@
+# 2020-02-23
+#
+# 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.
+#
+#***********************************************************************
+# Tests for functionality related to ANALYZE.
+#
+
+set testdir [file dirname $argv0]
+source $testdir/tester.tcl
+
+set testprefix analyzeG
+
+proc do_scan_order_test {tn sql expect} {
+  uplevel [list do_test $tn [subst -nocommands {
+    set res ""
+    db eval "explain query plan $sql" {
+      lappend res [set detail]
+    }
+    set res
+  }] [list {*}$expect]]
+}
+
+#-------------------------------------------------------------------------
+# Test cases 1.* seek to verify that even if an index is not used, its
+# stat4 data may be used by the planner to estimate the number of
+# rows that match an unindexed constraint on the same column.
+#
+do_execsql_test 1.0 {
+  PRAGMA automatic_index = 0;
+  CREATE TABLE t1(a, x);
+  CREATE TABLE t2(b, y);
+  WITH s(i) AS (
+    SELECT 1 UNION ALL SELECT i+1 FROM s WHERE i<100
+  )
+  INSERT INTO t1 SELECT (i%50), NULL FROM s;
+  WITH s(i) AS (
+    SELECT 1 UNION ALL SELECT i+1 FROM s WHERE i<100
+  )
+  INSERT INTO t2 SELECT (CASE WHEN i<95 THEN 44 ELSE i END), NULL FROM s;
+}
+
+# Join tables t1 and t2. Both contain 100 rows. (a=44) matches 2 rows
+# in "t1", (b=44) matches 95 rows in table "t2". But the planner doesn't
+# know this, so it has no preference as to which order the tables are
+# scanned in. In practice this means that tables are scanned in the order
+# they are specified in in the FROM clause.
+do_scan_order_test 1.1.1 {
+  SELECT * FROM t1, t2 WHERE a=44 AND b=44;
+} {
+  {SCAN TABLE t1} {SCAN TABLE t2}
+}
+do_scan_order_test 1.1.2 {
+  SELECT * FROM t2, t1 WHERE a=44 AND b=44 
+} {
+  {SCAN TABLE t2} {SCAN TABLE t1} 
+}
+
+do_execsql_test 1.2 {
+  CREATE INDEX t2b ON t2(b);
+  ANALYZE;
+}
+
+# Now, with the ANALYZE data, the planner knows that (b=44) matches a 
+# large number of rows. So it elects to scan table "t1" first, regardless
+# of the order in which the tables are specified in the FROM clause.
+do_scan_order_test 1.3.1 {
+  SELECT * FROM t1, t2 WHERE a=44 AND b=44;
+} {
+  {SCAN TABLE t1} {SCAN TABLE t2}
+}
+do_scan_order_test 1.3.2 {
+  SELECT * FROM t2, t1 WHERE a=44 AND b=44 
+} {
+  {SCAN TABLE t1} {SCAN TABLE t2} 
+}
+
+
+finish_test
+