By Sujith | March 30, 2019 | Posted in : SQL Server
SQL Server 2017 brings the best features of the Microsoft relational database engine to the enterprise Linux ecosystem, including SQL Server Agent, Azure Active Directory (Azure AD) authentication, best-in-class high availability/ disaster recovery, and unparalleled data security.
By Murali | March 15, 2021 | Posted in : SQL Server
Huge data blocks resides under single MDF file might cause a performance of the query and impact the application services. This blog help you to understand how we can the split the single MDF file into multiple data files.
ProxySQL is high performance SQL Proxy which mainly used for Load balancing. ProxySQL 2.0 has become GA and with new exiting features like consistent reads using GTID, Galera and MySQL group replication native support and more bug fixes.
Some notable features are below,
Removed the support for RHEL/CentOS 5, Debian 7 and Ubuntu 12.
Supports for systemd.
Run ProxySQL under proxysql user, earlier it was root.
For example,
In older version, ProxySQL runs as root user.
In 2.0 version, ProxySQL runs as proxysql user.
Replication hostgroups:
In mysql_replication_hostgroups table a new field added with the name of check_type, which accepts read_only,innodb_read_only and super_read_only.
GTID: A new table introduced in stats DB to maintain the GTID statistics.
We need to enable the “session_track_gtids” in MySQL end to track the GTID details. If it is enabled, then ProxySQL can track the GTID of the client requests. For this ProxySQL uses a process named “ProxySQL Binlog Reader”.
In ProxySQL we have below variable to specify how often the binlog reader to reconnect.
Below are the requirements to enable this feature,
Backend should be higher than 5.7.5 version and not MariaDB.
Binlog format should be ROW.
GTID should be enabled.
Stats tables:
A new additional column named “client_address” added in the “stats_mysql_query_digest” table. This column tracks the address of the client sending request. To achieve this we need to enable the below variable which newly included in the ProxySQL 2.0 version.
Default value is “FALSE”.
Example:
A new table added in “stats” DB named “mysql_errors” which collects the stats about queries and connections errors.
Another new table added in stats DB named “stats_mysql_global” which consists of ProxySQL status variables[Output as same as MySQL status variables].
General changes:
In query rule table, the “cache_empty_result” column is newly added. It has two values “1” or “0”. If it is disabled the empty results are not cached.
In mysql_servers table, weight value is increased to “10000000”.
Added the “PROXYSQL FLUSH QUERY CACHE” command to flush the caching.
The new variable named “mysql-query_digests_normalize_digest_text” is introduced. If it is enabled, the statistics related queries are stored in different hash table. It will reduce the memory usage.