Sometimes you have a many tag with same class and attribute with value but you need to find maximal value of attribute from that comman class In bellow you have same html tagpre classcode languagehtmlltulgtltli classtest dataid3gthiltligtltli classtest datai
For the past few years I’ve been writing and speaking about time-series storage, a problem inspired by what I help build at VividCortex and also my personal projects. I’ve been thinking about a related problem for much longer, but I haven’t had to work on it until now: ranking.
At VividCortex, we have a new tool called the Profiler. It allows you to rank within various categories of metrics, like MySQL or OS metrics, by a dimension, like count. You can rank top processes by total CPU time or memory, MySQL queries by execution time, and so on. We can do this for arbitrary time ranges.
The ranking is performed on the sums of values within each time range. If we’re ranking by CPU usage during a 300 second window, we look at the CPU usage measurements for each process at every second, sum those values up, …
[Read more]Time for another entry in the EXPLAIN FORMAT=JSON is cool! series of blog posts. This time we’ll discuss how using EXPLAIN FORMAT=JSON allows you to see that
cost_info
knows why the optimizer prefers one index to another.
Tables often have more than one index. Any of these indexes can be used to resolve query. The optimizer has to make a choice in this case. One of the metrics that can be used to help make the choice is the potential cost of the query evaluation.
For example, let’s take the table
titles
from the standard employees database:
…[Read more]Sometimes you face problem you cant get post data using thisinputpost when you fire httppost using AngularJS or Jquery I also face this issue i cant receive post value when i fire httppost in AngularJS But i found how to receive post data or json data in Codeigniter controller i
Are you building an IOT solution and want to know how to store
and retrieve your IOT data? Perhaps you're new to database
systems and want to learn how to use them while you explore the
exciting world of IOT.
This book is the answer for both scenarios; whether you're new to
IOT and want to know how to leverage MySQL in your solution or
you've wanted to learn more about MySQL, this book will provide
many of the answers you seek.
The book also covers how to design your IOT solution around your
data. Not only will you learn more about MySQL, but you will also
see how best to deploy MySQL in your IOT solution using low-cost
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Finally, the book will give you a thorough overview of how data
can be augmented and annotated to make it easier to glean the
golden nuggets of knowledge you seek while wading through your
sensor data. …
Hi Akileish,
If you replicate from Oracle to Oracle ,as example, and enable
DDL replication, it will create the same logical structure on the
target . Essentially the GoldenGate will replay the command to
create the index applying the mapping. Of course the internal
index structure like number of levels and leaf blocks may be
different. Speaking about other database engines it will depend
from supported operations for the replication. As example if you
replicate from Oracle to MySQL all DDL it is not going to work
since DDL replication is not supported for that configuration.
—
Gleb
In our previous post, we described how MySQL Master-HA (MHA) performs a so called slave promotion (also known as master failover) and ensures all remaining slaves in the topology get attached under the new master and become equal in data set.
Another failover solution is the MariaDB MaxScale proxy in combination with the MariaDB Replication Manager. Let’s look at how these two separate products can work together and perform a failover. We will also describe how you can use them.
MaxScale + MariaDB Replication Manager MaxScale
For those unfamiliar with MaxScale: MaxScale is a versatile database proxy written in C that supports not only intelligent query routing but can also function as both a binlog server and intermediate master. MaxScale consists of five plugins: Authentication, Protocol, Monitor, Routing, …
[Read more]In our MySQL replication tutorial we have covered different aspects of replication including master failover by performing a slave promotion using ClusterControl. The slave promotion will turn a slave into the new master, and re-attach the remaining slaves in the topology under the new master. Keep in mind that ClusterControl will not perform an automated slave promotion in the current version. We do have a helper to find the most advanced slave (Cluster drop down: Find Most Advanced Slave) to determine the best candidate slave.
Another thing to keep in mind is that, as of time of writing, ClusterControl only supports replication topologies using MySQL GTID. You can add your existing MariaDB based replication topology to ClusterControl but promoting slaves can …
[Read more]On an earlier post I wrote about real time query monitoring on MySQL with a third party tool and without one. The script is useful as it works with MySQL 5.5 and later. However, if you're using a later version of MySQL, you should look at the SYS schema. It is a collection of views, functions and procedures to help MySQL administrators get insight in to MySQL Database usage. It's available to