sqlite/test/scanstatus2.test

# 2014 November 1
#
# 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 scanstatus2

ifcapable !scanstatus {
  finish_test
  return
}

do_execsql_test 1.0 {
  CREATE TABLE t1(a, b);
  CREATE TABLE t2(x, y);
  INSERT INTO t1 VALUES(1, 2);
  INSERT INTO t1 VALUES(3, 4);
  INSERT INTO t2 VALUES('a', 'b');
  INSERT INTO t2 VALUES('c', 'd');
  INSERT INTO t2 VALUES('e', 'f');
}

proc do_zexplain_test {v2 tn sql res} {
  db eval $sql
  set stmt [db version -last-stmt-ptr]
  set idx 0
  set ret [list]

  set cmd sqlite3_stmt_scanstatus
  set f [list]
  if {$v2} { lappend f complex }

  while {1} {
    set r [sqlite3_stmt_scanstatus -flags $f $stmt $idx]
    if {[llength $r]==0} break
    lappend ret [dict get $r zExplain]
    incr idx
  }
  uplevel [list do_test $tn [list set {} $ret] [list {*}$res]]
}

proc get_cycles {stmt} {
  set r [sqlite3_stmt_scanstatus $stmt -1]
  dict get $r nCycle
}

proc foreach_scan {varname stmt body} {
  upvar $varname var

  for {set ii 0} {1} {incr ii} {
    set r [sqlite3_stmt_scanstatus -flags complex $stmt $ii]
    if {[llength $r]==0} break
    array set var $r
    uplevel $body
  }
}

proc get_eqp_graph {stmt iPar nIndent} {
  set res ""
  foreach_scan A $stmt {
    if {$A(iParentId)==$iPar} {
      set txt $A(zExplain)
      if {$A(nCycle)>=0} {
        append txt " (nCycle=$A(nCycle))"
      }
      append res "[string repeat - $nIndent]$txt\n"
      append res [get_eqp_graph $stmt $A(iSelectId) [expr $nIndent+2]]
    }
  }
  set res
}

proc get_graph {stmt} {
  set nCycle [get_cycles $stmt]
  set res "QUERY (nCycle=$nCycle)\n"
  append res [get_eqp_graph $stmt 0 2]
}

proc do_graph_test {tn sql res} {
  db eval $sql
  set stmt [db version -last-stmt-ptr]

  set graph [string trim [get_graph $stmt]]
  set graph [regsub -all {nCycle=[0-9]+} $graph nCycle=nnn]
  uplevel [list do_test $tn [list set {} $graph] [string trim $res]]
}


do_zexplain_test 0 1.1 {
  SELECT (SELECT a FROM t1 WHERE b=x) FROM t2 WHERE y=2
} {
  {SCAN t2}
  {SCAN t1}
}
do_zexplain_test 1 1.2 {
  SELECT (SELECT a FROM t1 WHERE b=x) FROM t2 WHERE y=2
} {
  {SCAN t2}
  {CORRELATED SCALAR SUBQUERY 1}
  {SCAN t1}
}

do_graph_test 1.3 {
  SELECT (SELECT a FROM t1 WHERE b=x) FROM t2 WHERE y=2
} {
QUERY (nCycle=nnn)
--SCAN t2
--CORRELATED SCALAR SUBQUERY 1 (nCycle=nnn)
----SCAN t1
}

do_graph_test 1.4 {
  WITH v2(x,y) AS MATERIALIZED (
    SELECT x,y FROM t2
  )
  SELECT * FROM t1, v2 ORDER BY y;
} {
QUERY (nCycle=nnn)
--MATERIALIZE v2 (nCycle=nnn)
----SCAN t2
--SCAN v2
--SCAN t1
--USE TEMP B-TREE FOR ORDER BY
}

finish_test