From 8dd2f2937cc1957bbd23820d2ec63b0b92534313 Mon Sep 17 00:00:00 2001
From: Denis Khalikov <denis.khalikov@mariadb.com>
Date: Tue, 11 May 2021 22:16:43 +0300
Subject: [PATCH] MCOL-4407 and condtion does not work when HWM >
 columnstore_string_scan_threshold - 1

---
 .../columnstore/bugfixes/mcol-4407.result     | 32 ++++++++++++++
 .../columnstore/bugfixes/mcol-4407.test       | 44 +++++++++++++++++++
 primitives/linux-port/dictionary.cpp          | 18 ++++++++
 3 files changed, 94 insertions(+)
 create mode 100644 mysql-test/columnstore/bugfixes/mcol-4407.result
 create mode 100644 mysql-test/columnstore/bugfixes/mcol-4407.test

diff --git a/mysql-test/columnstore/bugfixes/mcol-4407.result b/mysql-test/columnstore/bugfixes/mcol-4407.result
new file mode 100644
index 000000000..031934208
--- /dev/null
+++ b/mysql-test/columnstore/bugfixes/mcol-4407.result
@@ -0,0 +1,32 @@
+DROP DATABASE IF EXISTS mcol_4407;
+CREATE DATABASE mcol_4407;
+USE mcol_4407;
+DROP TABLE IF EXISTS `sictable`;
+/* Bug when HWM > scan_threshold - 1 */
+set max_recursive_iterations=6282;
+CREATE TABLE `sictable`
+  (
+`serialno`    VARCHAR(20)    NOT NULL
+)
+ENGINE=Columnstore
+DEFAULT CHARSET=utf8
+;
+INSERT INTO `sictable`  (
+with recursive series as (
+select 1 as id union all
+select id +1 as id from series
+where id < 6281)
+select lpad(id,11,'0') from series);
+SELECT  `serialno`
+FROM  `sictable`
+WHERE  `serialno` = '00000000029' AND  `serialno` = '00000006256';
+serialno
+SELECT  `serialno`
+FROM  `sictable`
+WHERE  `serialno` = '00000000029' AND  `serialno` = '00000000029';
+serialno
+00000000029
+/* Default value */
+set max_recursive_iterations=1000;
+DROP TABLE `sictable`;
+DROP DATABASE mcol_4407;
diff --git a/mysql-test/columnstore/bugfixes/mcol-4407.test b/mysql-test/columnstore/bugfixes/mcol-4407.test
new file mode 100644
index 000000000..a834fb5bf
--- /dev/null
+++ b/mysql-test/columnstore/bugfixes/mcol-4407.test
@@ -0,0 +1,44 @@
+--source ../include/have_columnstore.inc
+
+-- disable_warnings
+DROP DATABASE IF EXISTS mcol_4407;
+-- enable_warnings
+
+CREATE DATABASE mcol_4407;
+USE mcol_4407;
+
+-- disable_warnings
+DROP TABLE IF EXISTS `sictable`;
+-- enable_warnings
+
+/* Bug when HWM > scan_threshold - 1 */
+set max_recursive_iterations=6282;
+
+CREATE TABLE `sictable`
+  (
+     `serialno`    VARCHAR(20)    NOT NULL
+  )
+    ENGINE=Columnstore
+    DEFAULT CHARSET=utf8
+  ;
+
+INSERT INTO `sictable`  (
+with recursive series as (
+select 1 as id union all
+select id +1 as id from series
+where id < 6281)
+select lpad(id,11,'0') from series);
+
+SELECT  `serialno`
+FROM  `sictable`
+WHERE  `serialno` = '00000000029' AND  `serialno` = '00000006256';
+
+SELECT  `serialno`
+FROM  `sictable`
+WHERE  `serialno` = '00000000029' AND  `serialno` = '00000000029';
+
+/* Default value */
+set max_recursive_iterations=1000;
+
+DROP TABLE `sictable`;
+DROP DATABASE mcol_4407;
diff --git a/primitives/linux-port/dictionary.cpp b/primitives/linux-port/dictionary.cpp
index 2403cc99b..3b9cc6420 100644
--- a/primitives/linux-port/dictionary.cpp
+++ b/primitives/linux-port/dictionary.cpp
@@ -495,6 +495,24 @@ void PrimitiveProcessor::p_Dictionary(const DictInput* in,
 
         if (eqFilter)
         {
+            // MCOL-4407.
+            // Support filters:
+            // `where key = value0 and key = value1 {and key = value2}`
+            //
+            // The problem occurs only when HWM > columnstore_string_scan_threshold - 1
+            // because in this case:
+            // CS uses `tryCombineDictionary` which combines `DictStep`s into one as result
+            // `eqFilter` has more than 1 filter and applies the logic below which is `or` by
+            // default.
+            // Note: The case HWM <= columnstore_string_scan_threshold - 1 has the same problem,
+            // function `p_TokenByScan`, but it does not occur because `tryCombineDictionaryScan`
+            // was turned off.
+            if (eqFilter->size() > 1 && in->BOP == BOP_AND && eqOp == COMPARE_EQ)
+              goto no_store;
+
+            if (eqFilter->size() > 1 && in->BOP == BOP_OR && eqOp == COMPARE_NE)
+                goto store;
+
             // MCOL-1246 Trim whitespace before match
             string strData((char*)sigptr.data, sigptr.len);
             boost::trim_right_if(strData, boost::is_any_of(" "));