Bug #25997748: MIGRATE FROM HASH TO STD::UNORDERED_MAP [patch 6, noclose]

More conversions from HASH, a bit all over (authentication, stored
procedures, session tracker).

Change-Id: Id6c616ab4cedd41ac4e27d9b314a3da19c5a84e2

Author: Steinar H. Gunderson

mysql-test/r/deprecate_eof.result

@@ -170,10 +170,10 @@ SELECT f1();
 f1()
 6
 -- Tracker : SESSION_TRACK_SYSTEM_VARIABLES
--- character_set_connection
--- utf8mb4
 -- character_set_client
 -- utf8mb4
+-- character_set_connection
+-- utf8mb4
 -- character_set_results
 -- big5
 
@@ -185,10 +185,10 @@ SELECT * FROM v1;
 f1()
 6
 -- Tracker : SESSION_TRACK_SYSTEM_VARIABLES
--- character_set_connection
--- utf8mb4
 -- character_set_client
 -- utf8mb4
+-- character_set_connection
+-- utf8mb4
 -- character_set_results
 -- big5
 
@@ -243,10 +243,10 @@ SELECT f4();
 f4()
 1
 -- Tracker : SESSION_TRACK_SYSTEM_VARIABLES
--- character_set_connection
--- utf8mb4
 -- character_set_client
 -- utf8mb4
+-- character_set_connection
+-- utf8mb4
 -- character_set_results
 -- utf8
 

mysql-test/r/session_tracker.result

@@ -27,10 +27,10 @@ SELECT @@session.character_set_client, @@session.character_set_results, @@sessio
 utf8mb4	utf8mb4	utf8mb4
 SET NAMES 'utf8';
 -- Tracker : SESSION_TRACK_SYSTEM_VARIABLES
--- character_set_connection
--- utf8
 -- character_set_client
 -- utf8
+-- character_set_connection
+-- utf8
 -- character_set_results
 -- utf8
 
@@ -39,10 +39,10 @@ SELECT @@session.character_set_client, @@session.character_set_results, @@sessio
 utf8	utf8	utf8
 SET NAMES 'big5';
 -- Tracker : SESSION_TRACK_SYSTEM_VARIABLES
--- character_set_connection
--- big5
 -- character_set_client
 -- big5
+-- character_set_connection
+-- big5
 -- character_set_results
 -- big5
 
@@ -279,21 +279,21 @@ SET @@session.tx_isolation='READ-COMMITTED';
 END;|
 CALL my_proc;
 -- Tracker : SESSION_TRACK_SYSTEM_VARIABLES
--- tx_isolation
--- READ-COMMITTED
 -- autocommit
 -- OFF
 -- time_zone
 -- -06:00
+-- tx_isolation
+-- READ-COMMITTED
 
 CALL my_proc;
 -- Tracker : SESSION_TRACK_SYSTEM_VARIABLES
--- tx_isolation
--- READ-COMMITTED
 -- autocommit
 -- OFF
 -- time_zone
 -- -06:00
+-- tx_isolation
+-- READ-COMMITTED
 
 DROP PROCEDURE my_proc;
 # Testing with unknown/invalid system variables.
@@ -509,10 +509,10 @@ SET @@session.session_track_state_change=ON;
 expect 1
 SET NAMES 'utf8';
 -- Tracker : SESSION_TRACK_SYSTEM_VARIABLES
--- character_set_connection
--- utf8
 -- character_set_client
 -- utf8
+-- character_set_connection
+-- utf8
 -- character_set_results
 -- utf8
 
@@ -523,10 +523,10 @@ SET @@session.session_track_state_change=OFF;
 # Change system variable
 SET NAMES 'utf8';
 -- Tracker : SESSION_TRACK_SYSTEM_VARIABLES
--- character_set_connection
--- utf8
 -- character_set_client
 -- utf8
+-- character_set_connection
+-- utf8
 -- character_set_results
 -- utf8
 

plugin/rewriter/rewriter.cc

@@ -38,36 +38,30 @@ using rules_table_service::Cursor;
 using Mysql::Nullable;
 namespace messages = rewriter_messages;
 
-/**
-  @file rewriter.cc
-  Implementation of the Rewriter class's member functions.
-*/
-
+namespace {
 
-/** Functions used in the hash */
-static const uchar *get_rule_hash_code(const uchar *entry, size_t *length)
+std::string hash_key_from_digest(const uchar *digest)
 {
-  const Rule *rule= pointer_cast<const Rule*>(entry);
-  *length= PARSER_SERVICE_DIGEST_LENGTH;
-  const uchar *digest= pointer_cast<const uchar*>(rule->digest_buffer());
-  return digest;
+  return std::string(pointer_cast<const char *>(digest),
+                     PARSER_SERVICE_DIGEST_LENGTH);
 }
 
+}  // namespace
 
-static void free_rule(void *entry) { delete pointer_cast<Rule*>(entry); }
+/**
+  @file rewriter.cc
+  Implementation of the Rewriter class's member functions.
+*/
 
 
 Rewriter::Rewriter()
 {
-  my_hash_init(&m_digests, &my_charset_bin, 10,
-               PARSER_SERVICE_DIGEST_LENGTH,
-               get_rule_hash_code,
-               free_rule, 0,
-               PSI_INSTRUMENT_ME);
 }
 
 
-Rewriter::~Rewriter() { my_hash_free(&m_digests); }
+Rewriter::~Rewriter()
+{
+}
 
 
 bool Rewriter::load_rule(MYSQL_THD thd, Persisted_rule *diskrule)
@@ -79,7 +73,8 @@ bool Rewriter::load_rule(MYSQL_THD thd, Persisted_rule *diskrule)
   switch (load_status)
   {
   case Rule::OK:
-    my_hash_insert(&m_digests, pointer_cast<uchar*>(memrule_ptr.release()));
+    m_digests.emplace(hash_key_from_digest(memrule_ptr->digest_buffer()),
+                      std::move(memrule_ptr));
     diskrule->message= Nullable<string>();
     diskrule->pattern_digest= services::print_digest(memrule->digest_buffer());
     diskrule->normalized_pattern= memrule->normalized_pattern();
@@ -139,7 +134,7 @@ void Rewriter::do_refresh(MYSQL_THD session_thd)
     m_refresh_status= REWRITER_ERROR_TABLE_MALFORMED;
     DBUG_VOID_RETURN;
   }
-  my_hash_reset(&m_digests);
+  m_digests.clear();
 
   for (; c != rules_table_service::end(); ++c)
   {
@@ -209,24 +204,19 @@ Rewriter::Load_status Rewriter::refresh(MYSQL_THD thd)
 
 Rewrite_result Rewriter::rewrite_query(MYSQL_THD thd, const uchar *key)
 {
-  HASH_SEARCH_STATE state;
   Rewrite_result result;
 
-  Rule *rule= pointer_cast<Rule*>(my_hash_first(&m_digests, key,
-                                                PARSER_SERVICE_DIGEST_LENGTH,
-                                                &state));
-  while (rule != NULL)
+  auto it_range= m_digests.equal_range(hash_key_from_digest(key));
+  for (auto it= it_range.first; it != it_range.second; ++it)
   {
+    Rule *rule= it->second.get();
     result.digest_matched= true;
     if (rule->matches(thd))
     {
       result= rule->create_new_query(thd);
       if (result.was_rewritten)
         return result;
     }
-    rule= pointer_cast<Rule*>(my_hash_next(&m_digests, key,
-                                           PARSER_SERVICE_DIGEST_LENGTH,
-                                           &state));
   }
 
   result.was_rewritten= false;

plugin/rewriter/rewriter.h

@@ -18,8 +18,10 @@
 
 #include "my_config.h"
 
-#include <hash.h>
+#include <memory>
+#include <string>
 
+#include "map_helpers.h"
 #include "my_inttypes.h"
 #include "rule.h"
 
@@ -58,7 +60,7 @@ class Rewriter {
     that fail to load, this number will be lower than the number of rows in
     the database.
   */
-  int get_number_loaded_rules() const { return m_digests.records; }
+  int get_number_loaded_rules() const { return m_digests.size(); }
 
   ~Rewriter();
 
@@ -86,7 +88,8 @@ class Rewriter {
   Rewriter::Load_status m_refresh_status;
 
   /// The in-memory rules hash table.
-  HASH m_digests;
+  malloc_unordered_multimap<std::string, std::unique_ptr<Rule>>
+    m_digests{PSI_INSTRUMENT_ME};
 
   /// Loads the rule retrieved from the database in the hash table.
   bool load_rule(MYSQL_THD thd, Persisted_rule *diskrule);