MCOL-4728 Query with unusual use of aggregate functions on ColumnStore table crashes MariaDB Server

After an AggreateColumn corresponding to SUM(1+1) is created,
it is pushed to the list:

    gwi.count_asterisk_list.push_back(ac)

Later, in getSelectPlan(), the expression SUM(1+1) was erroneously
treated as a constant:

  if (!hasNonSupportItem && !nonConstFunc(ifp) && !(parseInfo & AF_BIT) && tmpVec.size() == 0)
  {
     srcp.reset(buildReturnedColumn(item, gwi, gwi.fatalParseError));

This code freed the original AggregateColumn and replaced to a ConstantColumn.

But gwi.count_asterisk_list still pointer to the freed AggregateColumn().

The expression SUM(1+1) was treated as a constant because tmpVec
was empty due to a bug in this code:

                    // special handling for count(*). This should not be treated as constant.
                    if (isp->argument_count() == 1 &&
                            ( sfitempp[0]->type() == Item::CONST_ITEM &&
                                (sfitempp[0]->cmp_type() == INT_RESULT ||
                                 sfitempp[0]->cmp_type() == STRING_RESULT ||
                                 sfitempp[0]->cmp_type() == REAL_RESULT ||
                                 sfitempp[0]->cmp_type() == DECIMAL_RESULT)
                            )
                        )
                    {
                        field_vec.push_back((Item_field*)item); //dummy

Notice, it handles only aggregate functions with explicit literals
passed as an argument, while it does not handle constant expressions
such as 1+1.

Fix:

- Adding new classes ConstantColumnNull, ConstantColumnString,
  ConstantColumnNum, ConstantColumnUInt, ConstantColumnSInt,
  ConstantColumnReal, ValStrStdString, to reuse the code easier.

- Moving a part of the code from the case branch handling CONST_ITEM
  in buildReturnedColumn() into a new function
  newConstantColumnNotNullUsingValNativeNoTz(). This
  makes the code easier to read and to reuse in the future.

- Adding a new function newConstantColumnMaybeNullFromValStrNoTz().
  Removing dulplicate code from !!!four!!! places, using the new
  function instead.

- Adding a function isSupportedAggregateWithOneConstArg() to
  properly catch all constant expressions. Using the new function parse_item()
  in the code commented as "special handling for count(*)".
  Now it pushes all constant expressions to field_vec, not only
  explicit literals.

- Moving a part of the code from buildAggregateColumn()
  to a helper function processAggregateColumnConstArg().
  Using processAggregateColumnConstArg() in the CONST_ITEM
  and NULL_ITEM branches.

- Adding a new branch in buildReturnedColumn() handling FUNC_ITEM.
  If a function has constant arguments, a ConstantColumn() is
  immediately created, without going to
  buildArithmeticColumn()/buildFunctionColumn().

- Reusing isSupportedAggregateWithOneConstArg()
  and processAggregateColumnConstArg() in buildAggregateColumn().
  A new branch catches aggregate function has only one constant argument
  and immediately creates a single ConstantColumn without
  traversing to the argument sub-components.

mysql-test/columnstore/bugfixes/mcol-4728.result

@@ -0,0 +1,63 @@
+DROP DATABASE IF EXISTS mcol_4728;
+CREATE DATABASE mcol_4728;
+USE mcol_4728;
+SET columnstore_select_handler=ON;
+CREATE TABLE t1 (a INT) ENGINE=ColumnStore;
+SELECT SUM(0+0)-SUM(0+0) FROM t1;
+SUM(0+0)-SUM(0+0)
+NULL
+SELECT SUM(0) FROM t1;
+SUM(0)
+NULL
+SELECT COUNT(0) FROM t1;
+COUNT(0)
+0
+SELECT COUNT(NULL) FROM t1;
+COUNT(NULL)
+0
+SELECT COUNT(COALESCE(NULL)) FROM t1;
+COUNT(COALESCE(NULL))
+0
+SELECT MAX(0) FROM t1;
+MAX(0)
+NULL
+SELECT SUM(1)+1 FROM t1;
+SUM(1)+1
+NULL
+SELECT SUM(COALESCE(1))+1 FROM t1;
+SUM(COALESCE(1))+1
+NULL
+SELECT sum(rand(0))+1 FROM t1;
+sum(rand(0))+1
+NULL
+INSERT INTO t1 VALUES (100);
+SELECT SUM(0+0)-SUM(0+0) FROM t1;
+SUM(0+0)-SUM(0+0)
+0
+SELECT SUM(0) FROM t1;
+SUM(0)
+0
+SELECT COUNT(0) FROM t1;
+COUNT(0)
+1
+SELECT COUNT(NULL) FROM t1;
+COUNT(NULL)
+0
+SELECT COUNT(COALESCE(NULL)) FROM t1;
+COUNT(COALESCE(NULL))
+0
+SELECT MAX(0) FROM t1;
+MAX(0)
+0
+SELECT SUM(1)+1 FROM t1;
+SUM(1)+1
+2
+SELECT SUM(COALESCE(1))+1 FROM t1;
+SUM(COALESCE(1))+1
+2
+SELECT sum(rand(0))+1 FROM t1;
+sum(rand(0))+1
+1.1552204276949358
+DROP TABLE t1;
+DROP DATABASE mcol_4728;
+USE test;

mysql-test/columnstore/bugfixes/mcol-4728.test

@@ -0,0 +1,38 @@
+--source ../include/have_columnstore.inc
+
+--disable_warnings
+DROP DATABASE IF EXISTS mcol_4728;
+--enable_warnings
+
+CREATE DATABASE mcol_4728;
+USE mcol_4728;
+
+SET columnstore_select_handler=ON;
+CREATE TABLE t1 (a INT) ENGINE=ColumnStore;
+
+SELECT SUM(0+0)-SUM(0+0) FROM t1;
+SELECT SUM(0) FROM t1;
+SELECT COUNT(0) FROM t1;
+SELECT COUNT(NULL) FROM t1;
+SELECT COUNT(COALESCE(NULL)) FROM t1;
+SELECT MAX(0) FROM t1;
+SELECT SUM(1)+1 FROM t1;
+SELECT SUM(COALESCE(1))+1 FROM t1;
+SELECT sum(rand(0))+1 FROM t1;
+
+INSERT INTO t1 VALUES (100);
+
+SELECT SUM(0+0)-SUM(0+0) FROM t1;
+SELECT SUM(0) FROM t1;
+SELECT COUNT(0) FROM t1;
+SELECT COUNT(NULL) FROM t1;
+SELECT COUNT(COALESCE(NULL)) FROM t1;
+SELECT MAX(0) FROM t1;
+SELECT SUM(1)+1 FROM t1;
+SELECT SUM(COALESCE(1))+1 FROM t1;
+SELECT sum(rand(0))+1 FROM t1;
+
+DROP TABLE t1;
+
+DROP DATABASE mcol_4728;
+USE test;

mysql-test/columnstore/bugfixes/suite.opt

@@ -0,0 +1 @@
+--plugin-load-add=$HA_COLUMNSTORE_SO

mysql-test/columnstore/bugfixes/suite.pm

@@ -0,0 +1,23 @@
+package My::Suite::ColumnStore;
+
+@ISA = qw(My::Suite);
+
+my $mcs_bin_dir_compiled=$::bindir . '/storage/columnstore/columnstore/bin';
+my $mcs_ins_dir_installed=$::bindir . '/bin';
+
+if (-d $mcs_bin_dir_compiled)
+{
+  $ENV{MCS_MCSSETCONFIG}=$mcs_bin_dir_compiled . "/mcsSetConfig";
+  $ENV{MCS_CPIMPORT}=$mcs_bin_dir_compiled . "/cpimport";
+  $ENV{MCS_SYSCATALOG_MYSQL_SQL}=$::mysqld_variables{'basedir'} . "/storage/columnstore/columnstore/dbcon/mysql/syscatalog_mysql.sql";
+}
+elsif (-d $mcs_ins_dir_installed)
+{
+  $ENV{MCS_MCSSETCONFIG}=$mcs_ins_dir_installed . "/mcsSetConfig";
+  $ENV{MCS_CPIMPORT}=$mcs_ins_dir_installed . "/cpimport";
+  $ENV{MCS_SYSCATALOG_MYSQL_SQL}=$::mysqld_variables{'basedir'} . "/share/columnstore/syscatalog_mysql.sql";
+}
+
+sub is_default { 0 }
+
+bless { };