Tag: Table

Feed: Planet MySQL; Author: Kristian Köhntopp; For the MySQL Million Challenge, I was going through the server syntax in order to understand what things can be created in the server. And now my OCD triggered. DDL is a mess. As a database developer, I want to be able to create server objects using the CREATE thing syntax. The server gives you that for the following things: DATABASE EVENT FUNCTION (and FUNCTION SONAME) INDEX LOGFILE GROUP (NDB only, not going to look at this) PROCEDURE RESOURCE GROUP ROLE SERVER SPATIAL REFERENCE SYSTEM TABLE TABLESPACE TRIGGER USER VIEW As a database developer ... Read More

Feed: Planet MySQL; Author: Kristian Köhntopp; We observe a large number of messages of the kind The table '../tmp/#sql…' is full In older Versions of MySQL, implied temporary tables are being created, whenever your EXPLAIN contained the phrase using temporary. In this case, MySQL would create an in-memory temporary table to materialize an intermediate query result, and then continue to process the data from there. If that temporary table was larger than some configurable limit, the temporary table would instead be converted to a MyISAM table on disk, streamed out, and then work would continue with this. This has a ... Read More

Feed: Planet MySQL; Author: Øystein Grøvlen; This blog post is inspired by Jesper's recent blog post on how the automatic update of InnoDB persistent statistics may never trigger if servers are restarted frequently. However, the matter is even worse! In this blog post I will show that even when the automatic recalculation is performed, there are no guarantees as to when the server will see the changes. Myths about persistent statistics I must admit that I, for a long time, believed in the myths I was told about when updates to InnoDB's index statistics become visible to the query optimizer ... Read More

Feed: Planet MySQL; Author: Alena Subotina; The article explores a bunch of popular methods to rename a MySQL table and provides handy worked examples that could be of utility to both beginning and experienced users. In one of our previous articles, we looked in detail at how to rename a database in MySQL. In this article, we are going to focus specifically on renaming tables in MySQL. Rename table operations are common. Quite often as business situations and business requirements change, it becomes necessary to change the name of tables in MySQL databases so that they had more meaningful names ... Read More

Feed: R-bloggers. Author: HighlandR. [This article was first published on HighlandR, and kindly contributed to R-bloggers]. (You can report issue about the content on this page here) Want to share your content on R-bloggers? click here if you have a blog, or here if you don't. After a very long , R free hiatus (I don’t recommend it) I’m back on the R train, destination unknown. I had a bit of spare time last night, and remembered I had not done a PreppinData challenge for a while. In fact, the last one I did was week 8, and they are ... Read More

Feed: Recent Announcements. Amazon Web Services, Inc. (AWS), an Amazon.com company (NASDAQ: AMZN), extends Automatic Table Optimization to modify column compression encodings. This new capability maintains the optimal compression encodings in Amazon Redshift database tables on an ongoing basis to achieve high performance and reduce the storage utilization. By using automation to manage column compression, customers can ensure that column compression encodings are always optimized in order to get the best possible performance. A compression encoding specifies the type of compression that is applied to data values in a column as rows are added to a table. Choosing the right ... Read More

Feed: Planet MySQL; Author: Jesper Krogh; Locking is an important concept in databases. They help regulate access to the data, so your SELECT queries return consistent results and DML and DDL statements leave the data and schema in a consistent state. For the data, there are four different transaction isolation levels that influence which locks are taken. The most two commonly used isolation levels are REPEATABLE READ (the default in InnoDB) and READ COMMITTED (the default in some other databases). Both of those are said to provide non-locking reads, but there is a little more to it than that. Selecting ... Read More

Feed: MariaDB Knowledge Base Article Feed. Author: . Description The Information Schema SQL_FUNCTIONS table contains the list of MariaDB functions. It contains a single column: The table is not a standard Information Schema table, and is a MariaDB extension. Example SELECT * FROM INFORMATION_SCHEMA.SQL_FUNCTIONS; +---------------------------+ | FUNCTION | +---------------------------+ | ADDDATE | | ADD_MONTHS | | BIT_AND | | BIT_OR | | BIT_XOR | | CAST | | COUNT | | CUME_DIST | | CURDATE | | CURTIME | | DATE_ADD | | DATE_SUB | | DATE_FORMAT | | DECODE | | DENSE_RANK | | EXTRACT | | FIRST_VALUE | ... Read More

Feed: MariaDB Knowledge Base Article Feed. Author: . Description The Information Schema KEYWORDS table contains the list of MariaDB keywords. It contains a single column: The table is not a standard Information Schema table, and is a MariaDB extension. Example SELECT * FROM INFORMATION_SCHEMA.KEYWORDS; +-------------------------------+ | WORD | +-------------------------------+ | && | | <= | | <> | | != | | >= | | << | | >> | | <=> | | ACCESSIBLE | | ACCOUNT | | ACTION | | ADD | | ADMIN | | AFTER | | AGAINST | | AGGREGATE | | ALL | ... Read More

Feed: Recent Announcements. Amazon Aurora PostgreSQL-Compatible Edition supports the Partition Manager (pg_partman) extension in AWS GovCloud (US) regions. pg_partman is a PostgreSQL extension that helps you to manage both time series and serial-based table partition sets, including automatic management of partition creation and runtime maintenance. pg_partman works with PostgreSQL native partitioning so users can benefit from significant performance enhancements. You can view a list of all PostgreSQL extensions supported on RDS on the AWS User Guide. With this regional expansion, pg_partman is available in all commercial regions. For full feature parity list, head to our feature parity page, and to ... Read More