diff --git a/sql/ha_innodb.cc b/sql/ha_innodb.cc index b5962526d9e..1c6de24ed75 100644 --- a/sql/ha_innodb.cc +++ b/sql/ha_innodb.cc @@ -150,6 +150,19 @@ innobase_release_stat_resources( } } +/************************************************************************ +Call this function when mysqld passes control to the client. That is to +avoid deadlocks on the adaptive hash S-latch possibly held by thd. For more +documentation, see handler.cc. */ + +void +innobase_release_temporary_latches( +/*===============================*/ + void* innobase_tid) +{ + innobase_release_stat_resources((trx_t*)innobase_tid); +} + /************************************************************************ Increments innobase_active_counter and every INNOBASE_WAKE_INTERVALth time calls srv_active_wake_master_thread. This function should be used diff --git a/sql/ha_innodb.h b/sql/ha_innodb.h index d2639f39c5b..8031fa0aa29 100644 --- a/sql/ha_innodb.h +++ b/sql/ha_innodb.h @@ -208,3 +208,4 @@ int innodb_show_status(THD* thd); my_bool innobase_query_caching_of_table_permitted(THD* thd, char* full_name, uint full_name_len); +void innobase_release_temporary_latches(void* innobase_tid); diff --git a/sql/handler.cc b/sql/handler.cc index fb33888e91e..3fae7c3bd72 100644 --- a/sql/handler.cc +++ b/sql/handler.cc @@ -238,8 +238,10 @@ int ha_autocommit_or_rollback(THD *thd, int error) handler must be the same as in the binlog. arguments: + thd: the thread handle of the current connection log_file_name: latest binlog file name end_offset: the offset in the binlog file up to which we wrote + return value: 0 if success, 1 if error */ int ha_report_binlog_offset_and_commit(THD *thd, @@ -266,6 +268,34 @@ int ha_report_binlog_offset_and_commit(THD *thd, return error; } +/* + This function should be called when MySQL sends rows of a SELECT result set + or the EOF mark to the client. It releases a possible adaptive hash index + S-latch held by thd in InnoDB and also releases a possible InnoDB query + FIFO ticket to enter InnoDB. To save CPU time, InnoDB allows a thd to + keep them over several calls of the InnoDB handler interface when a join + is executed. But when we let the control to pass to the client they have + to be released because if the application program uses mysql_use_result(), + it may deadlock on the S-latch if the application on another connection + performs another SQL query. In MySQL-4.1 this is even more important because + there a connection can have several SELECT queries open at the same time. + + arguments: + thd: the thread handle of the current connection + return value: always 0 +*/ + +int ha_release_temporary_latches(THD *thd) +{ +#ifdef HAVE_INNOBASE_DB + THD_TRANS *trans; + trans = &thd->transaction.all; + if (trans->innobase_tid) + innobase_release_temporary_latches(trans->innobase_tid); +#endif + return 0; +} + int ha_commit_trans(THD *thd, THD_TRANS* trans) { int error=0; diff --git a/sql/handler.h b/sql/handler.h index b9209d087a0..8f1d00f64b5 100644 --- a/sql/handler.h +++ b/sql/handler.h @@ -371,6 +371,7 @@ void ha_resize_key_cache(void); int ha_start_stmt(THD *thd); int ha_report_binlog_offset_and_commit(THD *thd, char *log_file_name, my_off_t end_offset); +int ha_release_temporary_latches(THD *thd); int ha_commit_trans(THD *thd, THD_TRANS *trans); int ha_rollback_trans(THD *thd, THD_TRANS *trans); int ha_autocommit_or_rollback(THD *thd, int error); diff --git a/sql/sql_class.cc b/sql/sql_class.cc index e5ba58a0543..a99d17b0ec4 100644 --- a/sql/sql_class.cc +++ b/sql/sql_class.cc @@ -463,6 +463,14 @@ bool select_send::send_data(List &items) String *packet= &thd->packet; DBUG_ENTER("send_data"); +#ifdef HAVE_INNOBASE_DB + /* We may be passing the control from mysqld to the client: release the + InnoDB adaptive hash S-latch to avoid thread deadlocks if it was reserved + by thd */ + if (thd->transaction.all.innobase_tid) + ha_release_temporary_latches(thd); +#endif + if (thd->offset_limit) { // using limit offset,count thd->offset_limit--; @@ -486,6 +494,14 @@ bool select_send::send_data(List &items) bool select_send::send_eof() { +#ifdef HAVE_INNOBASE_DB + /* We may be passing the control from mysqld to the client: release the + InnoDB adaptive hash S-latch to avoid thread deadlocks if it was reserved + by thd */ + if (thd->transaction.all.innobase_tid) + ha_release_temporary_latches(thd); +#endif + /* Unlock tables before sending packet to gain some speed */ if (thd->lock) {