![]() What is a stored procedure?Ī stored procedure as it sounds is a procedure stored inside your database that you call with parameters. This blog post introduces the new “No stored procedures” option for MariaDB and MySQL introduced with HammerDB v4.9 and explains how to measure the difference between running with and without stored procedures. However, there can be a lack of understanding of the benefits that stored procedures bring or if you have a benchmarking tool or database that doesn’t support stored procedures, then you have nothing to compare against. Additionally, reviewing official TPC-C full disclosure reports highlighted that all vendors also use stored procedures. ![]() HammerDB has always used stored procedures as a design decision because the original benchmark was implemented as close as possible to the example workload in the TPC-C specification that uses stored procedures. See this post and this GitHub repository for working code.HammerDB uses stored procedures to achieve maximum throughput when benchmarking your database. I removed the code because it was buggy triggered MariaDB bugs. So I wrote a stored procedure which does the boring work for us: Of course, having to CREATE a TABLE each time is not very comfortable, even with table discovery. Look again at the example – everything will be clear. CONNECT supports table discovery, which means that it automatically knows which columns and types are needed.Ĭonfused? I hope not. So, we can use that query in all contexts where SELECT works.Īlso note that we don’t have to specify the table structure. But since this work is done by the CONNECT engine, from the MariaDB point of view we are just querying a table. This means that, when the table is queried, the CONNECT engine opens a connection to the local server, it executes SHOW MASTER STATUS, and it returns the results of that statement. Since I specified a SRCDEF table option, the data source is not a table in the server, it is the resultset of the specified query ( SHOW MASTER STATUS). In this case I defined a table which connects to a MariaDB/MySQL server ( TABLE_TYPE=MYSQL). Supported data sources include several file formats, remote DBMS’s and more. CONNECT is a storage engine which allows the users to read data from several kind of data sources as if they were regular SQL tables. How does the trick work? If you know CONNECT, probably you already guessed. | I'll do something with binlog.00000242965 |Īs you can see, with this trick I was able to use a cursor with SHOW MASTER STATUS. | CONCAT('I''ll do something with ', v_file, v_position) | SELECT CONCAT('I''ll do something with ', v_file, v_position) SELECT `File`, `Position` FROM show_master_status I faced all these problems while developing STK/Unit and in other projects.īut MariaDB lets us workaround these limitations – and the funny thing is that probably its developers are not aware about this! Here is an example: CREATE OR REPLACE TABLE show_master_status This means that in some contexts you may have to deal to annoying resultsets, or perhaps you cannot call those procedures (within triggers or functions). However, stored procedures could return one or more resultsets too, and you cannot invoke them with DO. MariaDB and MySQL support the DO statement, which is identical to SELECT except that it doesn’t return any result. An example is CHECK TABLES: even if you don’t care about the resultset (which would be a serious limitation), you cannot execute it in a stored procedure or in a prepared statements. This means that there is no way to read the output of these statements within a stored procedure or trigger.Īlso, some statements cannot be executed in a stored procedures and/or in prepared statements. ![]() ![]()
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