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Displaying posts with tag: mongodb (reset)
Percona Live 2016 Call for Papers Open! Introducing: Community Voting

The Call for Papers for the fifth annual Percona Live Data Performance Conference and Expo (formerly MySQL Conference and Expo) taking place April 18-21, 2016, in Santa Clara, California, is now officially open!

Ask yourself… “Do I have…”

  • Fresh ideas?
  • Enlightening case studies?
  • Insight on best practices?
  • In-depth technical knowlege?

If the answer to any of these is “YES,” then you need to submit your proposal for a chance to speak at Percona Live 2016. Speaking is a great way to broaden not only the awareness of your company with an intelligent and engaged audience of software …

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Losing it?

Many years ago the MySQL team at Google implemented semi-sync replication courtesy of Wei Li. The use case for it was limited and the community was disappointed that it did not provide the semantics they wanted. Eventually group commit was implemented for binlog+InnoDB: first by the MySQL team at Facebook, then much better by MariaDB, and finally in upstream MySQL. With group commit some magic was added to give us lossless semisync and now we have automated, lossless and fast failover in MySQL without using extra replicas. This feature is a big deal. I look forward to solutions for MariaDB (via binlog server and MaxScale) and MySQL (via …

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Problems not worth fixing

I worked on a closed-source DBMS years ago and the development cycle was 1) code for 6 months 2) debug for 18 months. Part 2 was longer than part 1 because the customers have high expectations for quality and the product delivers on that. But it was also longer because some co-workers might not have been code complete after 6 months and were quietly extending part 1 into part 2.

I fixed many bugs during part 2. One that I remember was in the optimizer. Someone added code to detect and remove duplicate expressions (A and A and B --> A and B). Alas the algorithm was O(N*N). Analytics queries can have complex WHERE clauses and all queries were forced to pay the O(N*N) cost whether or not they had any duplicate expressions. 
The overhead for this feature was reasonable after I fixed the code but it raises an interesting question. Are some problems not worth the cost of prevention? Several times a year I see …

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My Guidebook for Percona Live Amsterdam, 2015 - Part I

Unfortunately I am not going to Percona Live Amsterdam 2015 that starts next week. Somebody has to work and keep those customers happy who prefer to work as usual even during such a festival.

I am still asking myself: if I'd be able to go there, what tutorials and sessions I'd like to attend (besides those I'd present)? "All of them" is not a correct answer, as often great and useful sessions happens at the same time in different places. So, I decided to create a list of sessions for myself (as a reminder to check slides at least after they are published), and I'd like to share it.

I tried to pick up one session …

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MongoDB and Percona TokuMX Security Guidelines

Several reports we’re published in the news about how easy it is to access data stored in some NoSQL systems, including MongoDB. This is not surprising because security was rather relaxed in earlier versions of MongoDB . This post lists some of the common vulnerabilities in MongoDB and Percona TokuMX.

Network Security

One key point is to ensure that the bind_ip setting is correctly adjusted: in MongoDB 2.4 and Percona TokuMX, it is not set which means that the server will listen to all available network interfaces. If proper firewall rules (iptables, Security Groups in AWS, …) are not in place, your dataset could easily be queried from anywhere in the world!

In MongoDB 2.6+, bind_ip is set by default to in the official .deb and .rpm packages. This is great from a security point of view, but remember that you’ll still have to adjust the setting if the application servers are not …

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Transactions with RocksDB

RocksDB has work-in-progress to support transactions via optimistic and pessimistic concurrency control. The features need more documentation but we have shared the API, additional code for pessimistic and optimistic and examples for pessimistic and optimistic. Concurrency control …

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How to configure AWR system

In this article, we introduce myawr and mongoawr system .

Read this PDF, you will learn how to configure them.

How to configure AWR system.

Write-heavy workload vs the MongoDB optimizer

We experienced wasted disk IO from the MySQL query optimizer a few years back and fixed it via FORCE INDEX hints. I think I am experiencing wasted disk IO from the MongoDB optimizer during recent tests with the insert benchmark.

The problem with MySQL requires a query for which more than one index can be used. The problem query was a single table SELECT statement. The optimizer must figure out the best index and calls the records_in_range method to determine the selectivity of the query predicates for each relevant index. For InnoDB tables the records_in_range method reads the b-tree leaf node that contains the first and last index entries that satisfy the predicates and …

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Checkpoint strikes back

In my recent benchmarks for MongoDB, we can see that the two engines WiredTiger and TokuMX struggle from periodical drops in throughput, which is clearly related to a checkpoint interval – and therefore I correspond it to a checkpoint activity.

The funny thing is that I thought we solved checkpointing issues in InnoDB once and for good. There are bunch of posts on this issue in InnoDB, dated some 4 years ago.  We did a lot of research back then working on a fix for Percona Server

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InnoDB vs TokuDB in LinkBench benchmark

Previously I tested Tokutek’s Fractal Trees (TokuMX & TokuMXse) as MongoDB storage engines – today let’s look into the MySQL area.

I am going to use modified LinkBench in a heavy IO-load.

I compared InnoDB without compression, InnoDB with 8k compression, TokuDB with quicklz compression.
Uncompressed datasize is 115GiB, and cachesize is 12GiB for InnoDB and 8GiB + 4GiB OS cache for TokuDB.

Important to note is that I used tokudb_fanout=128, which is only available in our latest Percona Server release.
I …

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