[t:2614], make tokudb_prelock_empty a session variable

git-svn-id: file:///svn/mysql/tokudb-engine/tokudb-engine@20227 c7de825b-a66e-492c-adef-691d508d4ae1

storage/tokudb/ha_tokudb.cc

@@ -2850,7 +2850,7 @@ void ha_tokudb::start_bulk_insert(ha_rows rows) {
     ai_metadata_update_required = false;
     abort_loader = false;
     if (share->try_table_lock) {
-        if (tokudb_prelock_empty && may_table_be_empty()) {
+        if (get_prelock_empty(thd) && may_table_be_empty()) {
             if (using_ignore || get_load_save_space(thd)) {
                 acquire_table_lock(transaction, lock_write);
             }

storage/tokudb/hatoku_hton.cc

@@ -91,6 +91,13 @@ static MYSQL_THDVAR_BOOL(load_save_space,
   NULL, 
   FALSE
   );
+static MYSQL_THDVAR_BOOL(prelock_empty,
+  0,
+  "Tokudb Prelock Empty Table",
+  NULL, 
+  NULL, 
+  TRUE
+  );
 
 
 static void tokudb_print_error(const DB_ENV * db_env, const char *db_errpfx, const char *buffer);
@@ -144,7 +151,6 @@ static const int tokudb_hton_name_length = sizeof(tokudb_hton_name) - 1;
 static u_int32_t tokudb_checkpointing_period;
 u_int32_t tokudb_write_status_frequency;
 u_int32_t tokudb_read_status_frequency;
-my_bool tokudb_prelock_empty;
 #ifdef TOKUDB_VERSION
 char *tokudb_version = (char*) TOKUDB_VERSION;
 #else
@@ -497,6 +503,9 @@ bool get_load_save_space(THD* thd) {
     return (THDVAR(thd, load_save_space) != 0);
 }
 
+bool get_prelock_empty(THD* thd) {
+    return (THDVAR(thd, prelock_empty) != 0);
+}
 
 typedef struct txn_progress_info {
     char status[200];
@@ -1179,7 +1188,6 @@ static MYSQL_SYSVAR_STR(version, tokudb_version, PLUGIN_VAR_READONLY, "TokuDB Ve
 static MYSQL_SYSVAR_UINT(init_flags, tokudb_init_flags, PLUGIN_VAR_READONLY, "Sets TokuDB DB_ENV->open flags", NULL, NULL, tokudb_init_flags, 0, ~0, 0);
 
 static MYSQL_SYSVAR_UINT(checkpointing_period, tokudb_checkpointing_period, 0, "TokuDB Checkpointing period", NULL, NULL, 60, 0, ~0L, 0);
-static MYSQL_SYSVAR_BOOL(prelock_empty, tokudb_prelock_empty, 0, "Tokudb Prelock Empty Table", NULL, NULL, TRUE);
 static MYSQL_SYSVAR_UINT(write_status_frequency, tokudb_write_status_frequency, 0, "TokuDB frequency that show processlist updates status of writes", NULL, NULL, 1000, 0, ~0L, 0);
 static MYSQL_SYSVAR_UINT(read_status_frequency, tokudb_read_status_frequency, 0, "TokuDB frequency that show processlist updates status of reads", NULL, NULL, 10000, 0, ~0L, 0);
 static MYSQL_SYSVAR_INT(fs_reserve_percent, tokudb_fs_reserve_percent, PLUGIN_VAR_READONLY, "TokuDB file system space reserve (percent free required)", NULL, NULL, 5, 0, 100, 0);

storage/tokudb/hatoku_hton.h

@@ -15,11 +15,11 @@ ulonglong get_write_lock_wait_time (THD* thd);
 ulonglong get_read_lock_wait_time (THD* thd);
 uint get_pk_insert_mode(THD* thd);
 bool get_load_save_space(THD* thd);
+bool get_prelock_empty(THD* thd);
 
 extern HASH tokudb_open_tables;
 extern pthread_mutex_t tokudb_mutex;
 extern pthread_mutex_t tokudb_meta_mutex;
-extern my_bool tokudb_prelock_empty;
 extern u_int32_t tokudb_write_status_frequency;
 extern u_int32_t tokudb_read_status_frequency;
 #endif //#ifdef _HATOKU_HTON