Changed in Percona Server 5.7¶

Percona Server for MySQL 5.7 is based on MySQL 5.7 and incorporates many of the improvements found in Percona Server for MySQL 5.6.

Features removed from Percona Server for MySQL 5.7 that were available in Percona Server for MySQL 5.6¶

Note

Percona Server 5.7 won’t be able to start if any of variables from these features are set in the server’s configuration file.

Some features that were present in Percona Server for MySQL 5.6 have been removed in Percona Server for MySQL 5.7. These are:

Handlersocket
- This feature might be included in a future release if HandlerSocket starts supporting 5.7.
Support for Fake Changes
- Instead of replica prefetching using the fake changes, a 5.7 intra-schema parallel replication replica should be used.
SHOW ENGINE INNODB STATUS no longer prints the count of active Read-Only transactions.
InnoDB redo log archiving has been removed due to lack of user uptake of the feature.

Changes in Percona Server 5.6 features¶

The minor Percona Server for MySQL version number (“y” in “5.a.b-x.y”) has been dropped to simplify Percona Server for MySQL versioning.
Performance Schema memory instrumentation support has been added to the

Audit Log Plugin, Metrics for scalability measurement, and PAM Authentication Plugin, and to the core server to track memory used by User Statistics, Per-query variable statement, XtraDB changed page tracking, and Thread Pool features.
Audit Log Plugin now produces diagnostics in a format consistent with the rest of the server.
The performance_schema.metadata_locks table now displays backup and binlog lock information too. The object_type column has two new valid values: backup, and binlog.
INFORMATION_SCHEMA.XTRADB_RSEG table schema has been changed to support new possible InnoDB page sizes. The zip_size column has been removed and replaced by new columns physical_page_size, logical_page_size, and is_compressed.
XTRADB_READ_VIEW table no longer contains the READ_VIEW_UNDO_NUMBER column, which was associated with unused code and always contained zero.
Interaction between --hidden- option modifier and session_track_system_variables has been implemented as follows: any variables with --hidden- modifier become hidden from the latter variable too. Thus, they should not be present there. Even if you never set session_track_system_variables, care must be taken if a variable contained in its default value (i.e. autocommit) is hidden.
Nested SET STATEMENT ... FOR SET STATEMENT ... FOR ... statements have a different effect in the innermost clause when the nested clauses set the same variables: in 5.6, the innermost assignment is effective, but, in 5.7, the outermost assignment is effective.
Utility user is treated as a SUPER user for the purposes of offline mode: utility user connections are not dropped if server switches to offline mode and new utility user connections can be established to such server.
The server will abort startup with an error message if conflicting enforce_storage_engine and disabled_storage_engines option values are specified, that is, if the enforced storage engine is in the list of disabled storage engines.

Features available in Percona Server for MySQL 5.6 that have been replaced with MySQL 5.7 features¶

Note

Percona Server 5.7 won’t be able to start if any of variables from these features are set in the server’s configuration file.

Some Percona Server for MySQL 5.6 features have been replaced by similar or equivalent MySQL 5.7 features, so we now keep the MySQL 5.7 implementations in Percona Server for MySQL 5.7. These are:

Lock-Free SHOW SLAVE STATUS NONBLOCKING has been replaced by a regular SHOW SLAVE STATUS implementation . Oracle implementation forbids calling it from a stored function.
Behavior corresponding to slow_query_log_timestamp_precision set

to microsecond is now the default, the variable itself and the behavior corresponding to the variable’s second value is removed.
Behavior corresponding to slow_query_log_timestamp_always set to TRUE

is now the default, the variable itself and the behavior corresponding to the variable’s FALSE value is removed.
Statement timeout feature has been replaced by Oracle Server-side SELECT statement timeouts implementation. Differences: the Oracle variable is named max_statement_time instead of max_statement_time; variable have_statement_timeout variable has been removed; the timeouts only apply for read-only SELECT .
Atomic write support on fusionIO devices with NVMFS has been replaced by Oracle implementation. It is no longer required to enable innodb_use_atomic_writes variable, and this variable has been removed. The atomic write support will be enabled, and the doublewrite buffer disabled, on supporting devices automatically. The Oracle implementation does not silently adjust innodb_flush_method to O_DIRECT if it has a different value. The user must set it to O_DIRECT explicitly, or atomic writes will not be enabled.
Online GTID migration patch has been replaced by an upstream variable gtid_mode made dynamic.
The Error Code Compatibility has been replaced by the multiple start-error-number directive in sql/share/errmsg-utf8.txt support.
Ignoring missing tables in mysqldump with --ignore-create-error option has been replaced by the more general upstream option –ignore-error option.
innodb_log_block_size has been replaced by innodb_log_write_ahead_size variable. To avoid read on write when the storage block size is not equal to 512 bytes, the latter should be set to the same value the former was. If innodb_log_block_size was set to non-default values, new log files must be created during the upgrade. This can be done by cleanly shutting down the service and removing the variable from my.cnf configuration and removing the old logs and starting the service again before doing the upgrade.
Extended secure-file-priv server option , which was used to disable LOAD DATA INFILE, SELECT INTO OUTFILE statements, and LOAD_FILE() function completely, has been replaced by upstream introducing NULL as a possible value to this variable. To migrate, any value-less settings must be replaced by NULL.
innodb_sched_priority_cleaner variable has been removed, as the effect of setting it to 39 ( corresponding to nice value of -20), is now enabled by default.
innodb_adaptive_hash_index_partitions has been replaced by innodb_adaptive_hash_index_parts .
In the default server setup (with InnoDB being the only one XA-capable storage engine), --tc-heuristic-recover=COMMIT is silently converted to ROLLBACK. If TokuDB or another XA-supporting 3^rd party storage engine is installed, --tc-heuristic-recover=ROLLBACK option is unavailable. The default value of tc-heuristic-recover option in Percona Server for MySQL 5.6 but not in MySQL 5.6 was NONE as a result of fix for upstream bug #70860. Since Oracle fixed the same bug in 5.7, the default value is OFF now.
innodb_log_checksum_algorithm feature has been replaced by innodb_log_checksums option. In particular, to get the effect of setting the innodb_log_checksum_algorithm to crc32, innodb_log_checksums should be set to ON, which is a default setting for this variable.
innodb_buffer_pool_populate server option and numa_interleave mysql_safe.sh option have been replaced by innodb_numa_interleave server option. Note that flush_caches option still remains.
Ability to change database for mysqlbinlog implementation has been replaced from MariaDB one with MySQL rewrite-db one. The feature is mostly identical with two differences: 1) multiple rewrite rules must be given as separate options, and the ability to list them in a single rule, separated by commas, is lost. That is, any --rewrite-db='a->b,c->d' occurrences must be replaced with --rewrite-db='a->b' --rewrite-db='c->d'. 2) Whitespace around database names is not ignored.
INFORMATION_SCHEMA.PROCESSLIST.TID column has been replaced by PERFORMANCE_SCHEMA.THREADS.THREAD_OS_ID column . If running under thread pool, THREAD_OS_ID column will always be NULL, whereas in the 5.6 implementation TID column showed either NULL or the assigned worker thread id at the moment.
innodb_foreground_preflush server variable has been removed as the upstream implemented a similar feature without a controlling option.
Log All Client Commands (syslog) feature has been replaced by Oracle mysql Logging implementation.
Support for Multiple user level locks per connection has been replaced by Oracle implementation, which is based on the same contributed patch by Kostja Osipov.
super-read-only option has been replaced by Oracle super_read_only variable implementation.
Mutex names in SHOW ENGINE INNODB MUTEX have been replaced by Oracle mutex name implementation.
Percona Server for MySQL now uses packaging similar to the upstream MySQL version. Most important change is that for Debian/Ubuntu upgrades you now need to run mysql_upgrade manually.

List of status variables that are no longer available in Percona Server for MySQL 5.7¶

Following status variables available in Percona Server for MySQL 5.6 are no longer present in Percona Server for MySQL 5.7:

Status Variables	Replaced by
Com_purge_archived	InnoDB redo log archiving has been removed due to lack of user uptake of the feature.
Com_purge_archived_before_date	InnoDB redo log archiving has been removed due to lack of user uptake of the feature.
read_views_memory	transaction descriptors replaced by the upstream implementation
descriptors_memory	transaction descriptors replaced by the upstream implementation
innodb_mem_total	This variable was always zero in 5.6 with the default innodb_use_sys_malloc setting
innodb_deadlocks	Information now available in INFORMATION_SCHEMA.INNODB_METRICS table (lock_deadlocks)
Innodb_ibuf_merges	Information now available in INFORMATION_SCHEMA.INNODB_METRICS table (ibuf_merges)
Innodb_ibuf_merged_deletes	Information now available in INFORMATION_SCHEMA.INNODB_METRICS table (ibuf_merges_delete)
Innodb_ibuf_merged_delete_marks	Information now available in INFORMATION_SCHEMA.INNODB_METRICS table (ibuf_merges_delete_mark)
Innodb_ibuf_discarded_deletes	Information now available in INFORMATION_SCHEMA.INNODB_METRICS table (ibuf_merges_discard_delete)
Innodb_ibuf_discarded_delete_marks	Information now available in INFORMATION_SCHEMA.INNODB_METRICS table (ibuf_merges_discard_delete_mark)
Innodb_ibuf_discarded_inserts	Information now available in INFORMATION_SCHEMA.INNODB_METRICS table (ibuf_merges_discard_insert)
Innodb_ibuf_merged_inserts	Information now available in INFORMATION_SCHEMA.INNODB_METRICS table (ibuf_merges_insert)
Innodb_ibuf_size	Information now available in INFORMATION_SCHEMA.INNODB_METRICS table (ibuf_size)
Innodb_s_lock_os_waits	Information now available in INFORMATION_SCHEMA.INNODB_METRICS table (innodb_rwlock_s_os_waits)
Innodb_s_lock_spin_rounds	Information now available in INFORMATION_SCHEMA.INNODB_METRICS table (innodb_rwlock_s_spin_rounds)
Innodb_s_lock_spin_waits	Information now available in INFORMATION_SCHEMA.INNODB_METRICS table (innodb_rwlock_s_spin_waits)
Innodb_x_lock_os_waits	Information now available in INFORMATION_SCHEMA.INNODB_METRICS table (innodb_rwlock_x_os_waits)
Innodb_x_lock_spin_rounds	Information now available in INFORMATION_SCHEMA.INNODB_METRICS table (innodb_rwlock_x_spin_rounds)
Innodb_x_lock_spin_waits	Information now available in INFORMATION_SCHEMA.INNODB_METRICS table (innodb_rwlock_x_spin_waits)
Innodb_current_row_locks	Information now available in INFORMATION_SCHEMA.INNODB_METRICS table (lock_row_lock_current_waits)
Innodb_history_list_length	Information now available in INFORMATION_SCHEMA.INNODB_METRICS table (trx_rseg_history_len)
Innodb_mutex_os_waits	SHOW ENGINE INNODB MUTEX presents the same information, but per-mutex instead of whole system aggregation
Innodb_mutex_spin_rounds	SHOW ENGINE INNODB MUTEX presents the same information, but per-mutex instead of whole system aggregation
Innodb_mutex_spin_waits	SHOW ENGINE INNODB MUTEX presents the same information, but per-mutex instead of whole system aggregation

List of system variables that are no longer available in Percona Server for MySQL 5.7¶

Following system variables available in Percona Server for MySQL 5.6 are no longer present in Percona Server for MySQL 5.7:

Waring

Percona Server for MySQL 5.7 won’t be able to start if some of these variables are set in the server’s configuration file.

System Variables	Feature Comment
gtid_deployment_step	Replaced by an upstream variable gtid_mode made dynamic.
innodb_fake_changes	Instead of replica prefetching using the fake changes, a 5.7 intra-schema parallel replication replica should be used.
innodb_locking_fake_changes	Instead of replica prefetching using the fake changes, a 5.7 intra-schema parallel replication replica should be used.
innodb_log_archive	InnoDB redo log archiving has been removed due to lack of user uptake of the feature.
innodb_log_arch_dir	InnoDB redo log archiving has been removed due to lack of user uptake of the feature.
innodb_log_arch_expire_sec	InnoDB redo log archiving has been removed due to lack of user uptake of the feature.
innodb_log_block_size	Replaced by upstream innodb_log_write_ahead_size variable. To avoid read on write when the storage block size is not equal to 512 bytes, the latter should be set to the same value the former was. If innodb_log_block_size was set to non-default values, new log files must be created during the upgrade. This can be done by cleanly shutting down the service and removing the variable from my.cnf configuration and removing the old logs and starting the service again before doing the upgrade.
max_statement_time	Replaced by upstream max_execution_time variable in Server-side SELECT statement timeouts implementation.
have_statement_timeout	Variable has been removed due to upstream feature implementation
innodb_use_atomic_writes	Variable has been removed due to upstream feature implementation
innodb_adaptive_hash_index_partitions	Replaced by upstream variable innodb_adaptive_hash_index_parts

Features ported from Percona Server for MySQL 5.6 to Percona Server for MySQL 5.7¶

Following features were ported from Percona Server for MySQL 5.6 to Percona Server for MySQL 5.7:

Feature Ported	Version
Improved Buffer Pool Scalability	Percona Server for MySQL 5.7.10-1
Improved InnoDB I/O Scalability	Percona Server for MySQL 5.7.10-1
Query Cache Enhancements	Percona Server for MySQL 5.7.10-1
Improved NUMA support	Percona Server for MySQL 5.7.10-1
Thread Pool	Percona Server for MySQL 5.7.10-1
XtraDB Performance Improvements for I/O-Bound Highly-Concurrent Workloads	Percona Server for MySQL 5.7.10-1
Suppress Warning Messages	Percona Server for MySQL 5.7.10-1
Improved MEMORY Storage Engine	Percona Server for MySQL 5.7.10-1
Restricting the number of binlog files	Percona Server for MySQL 5.7.10-1
Extended SELECT INTO OUTFILE/DUMPFILE	Percona Server for MySQL 5.7.10-1
Per-query variable statement	Percona Server for MySQL 5.7.10-1
Extended mysqlbinlog	Percona Server for MySQL 5.7.10-1
Slow Query Log Rotation and Expiration	Percona Server for MySQL 5.7.10-1
CSV engine mode for standard-compliant quote and comma parsing	Percona Server for MySQL 5.7.10-1
Support for PROXY protocol	Percona Server for MySQL 5.7.10-1
Per-session server-id	Percona Server for MySQL 5.7.10-1
Too Many Connections Warning	Percona Server for MySQL 5.7.10-1
Handle Corrupted Tables	Percona Server for MySQL 5.7.10-1
Percona Toolkit UDFs	Percona Server for MySQL 5.7.10-1
Kill Idle Transactions	Percona Server for MySQL 5.7.10-1
Enforcing Storage Engine	Percona Server for MySQL 5.7.10-1
Utility user	Percona Server for MySQL 5.7.10-1
Expanded Program Option Modifiers	Percona Server for MySQL 5.7.10-1
XtraDB changed page tracking	Percona Server for MySQL 5.7.10-1
PAM Authentication Plugin	Percona Server for MySQL 5.7.10-1
Expanded Fast Index Creation	Percona Server for MySQL 5.7.10-1
Backup Locks	Percona Server for MySQL 5.7.10-1
Audit Log Plugin	Percona Server for MySQL 5.7.10-1
Start transaction with consistent snapshot	Percona Server for MySQL 5.7.10-1
Extended SHOW GRANTS	Percona Server for MySQL 5.7.10-1
User Statistics	Percona Server for MySQL 5.7.10-1
Slow Query Log	Percona Server for MySQL 5.7.10-1
Extended Show Engine InnoDB Status	Percona Server for MySQL 5.7.10-1
Show Storage Engines	Percona Server for MySQL 5.7.10-1
Process List	Percona Server for MySQL 5.7.10-1
Misc. INFORMATION_SCHEMA Tables	Percona Server for MySQL 5.7.10-1
Thread Based Profiling	Percona Server for MySQL 5.7.10-1
Metrics for scalability measurement	Percona Server for MySQL 5.7.10-1
Response Time Distribution	Percona Server for MySQL 5.7.10-1

Last update: 2022-09-27