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Problem Description: A mysqld_safe instance is started. An InnoDB crash recovery begins which takes few seconds to complete. During this crash recovery process happening, another mysqld_safe instance is started with the same server startup parameters. Since the mysqld's pid file is absent during the crash recovery process the second instance assumes there is no other process and tries to acquire a lock on the ibdata files in the datadir. But this step fails and the 2nd instance keeps retrying 100 times each with a delay of 1 second. Now after the 100 attempts, the server goes down, but while going down it hits the mysqld_safe script's cleanup section and without any check it blindly deletes the socket and pid files. Since no lock is placed on the socket file, it gets deleted. Solution: We create a mysqld_safe.pid file in the datadir, which protects the presence server instance resources by storing the mysqld_safe's process id in it. We place a check if the mysqld_safe.pid file is existing in the datadir. If yes then we check if the pid it contains is an active pid or not. If yes again, then the scripts logs an error saying "A mysqld_safe instance is already running". Otherwise it will log the present mysqld_safe's pid into the mysqld_safe.pid file. |
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| .. | ||
| CMakeLists.txt | ||
| comp_sql.c | ||
| dheadgen.pl | ||
| fill_help_tables.sql | ||
| msql2mysql.sh | ||
| mysql_config.pl.in | ||
| mysql_config.sh | ||
| mysql_convert_table_format.sh | ||
| mysql_find_rows.sh | ||
| mysql_fix_extensions.sh | ||
| mysql_install_db.pl.in | ||
| mysql_install_db.sh | ||
| mysql_secure_installation.pl.in | ||
| mysql_secure_installation.sh | ||
| mysql_setpermission.sh | ||
| mysql_system_tables.sql | ||
| mysql_system_tables_data.sql | ||
| mysql_system_tables_fix.sql | ||
| mysql_test_data_timezone.sql | ||
| mysql_zap.sh | ||
| mysqlaccess.conf | ||
| mysqlaccess.sh | ||
| mysqlbug.sh | ||
| mysqld_multi.sh | ||
| mysqld_safe.sh | ||
| mysqldumpslow.sh | ||
| mysqlhotcopy.sh | ||