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Displaying posts with tag: order (reset)

Bulk insert into tables in sorted order to avoid deadlocks
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Shard-Query inserts data into a “coordinator” table when answering queries.   When there is a GROUP BY on the original query, the coordinator table contains a UNIQUE KEY over the GROUP BY attributes.   Shard-Query uses INSERT .. ON DUPLICATE KEY UPDATE in combination with bulk insert (insert into … values (),(),() ) when inserting into the table.

For what would normally be efficiency sake, Shard-Query sends queries to the shards using ORDER BY NULL which disables the filesort operation. Of course, this often results in the rows being sent back from the shards in random order.

Because the results are in …

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OpenDBCamp: Information Lifecycle Architecture
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The Open DB Camp in Sardinia 2011 has had a number of sessions on varying topics. Topics range from MySQL over MongoDB to replication and High Availability.

I decided to tap into the database expert resources present here at Sardegna Ricerche by discussing a non-database issue, where one can expert database experts to have insights beyond those of end users. And they did.

The topic was the particular case of information …



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MySQL Indexing Considerations Of Implementing A Priority Field In Your Application
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Introduction

If you, like me, are building or thinking of implementing a MySQL-powered application that has any need for prioritizing selecting certain data over other data, this article is for you.

Example

As a real world example, consider a queue-like video processing system. Your application receives new videos and processes them. The volume of incoming videos can at times be higher than the processing rate because the process is CPU bound, so occasionally a pretty long queue may form. You will try to process them as fast as you can but…

Note that I am using a queue here, …

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