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Showing entries 1 to 10 of 16 6 Older Entries

Displaying posts with tag: blob (reset)

Inserting large rows in MySQL and MariaDB
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As the maximum storage size for a LONGBLOB in MySQL is 4GB and the maximum max_allowed_packet size is 1GB I was wondering how it is possible to use the full LONGBLOB.

So I started testing this. I wrote a Python script with MySQL Connector/Python and used MySQL Sandbox to bring up an instance of MySQl 5.6.25.

One of the first settings I had to change was max_allowed_packet, which was expected. I set it to 1GB.

The next setting was less expected, it was innodb_log_file_size. The server enforces that the transaction has to fit in 10% of the InnoDB log files. So I had to set it to 2 files of 5G to be able to …

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Beware of MySQL BLOB Corruption in Older Versions
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Does your dataset consist of InnoDB tables with large BLOB data such that the data is stored in external BLOB pages? Was the dataset created in MySQL version 5.1 and below and without using the InnoDB plugin, or with InnoDB plugin but with MySQL version earlier than 5.1.55? If the answer to both the questions are "YES" then it could very well be that you have a hidden corruption lying around in your dataset.

The post Beware of MySQL BLOB Corruption in Older Versions appeared first on ovais.tariq.

Externally Stored Fields in InnoDB
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This article discusses the storage (inline and external) of field data in the InnoDB storage engine. All fields of variable length types like VARCHAR, VARBINARY, BLOB and TEXT can be stored inline within the clustered index record, or stored externally in separate BLOB pages outside of the index record (but within the same tablespace). All of these fields can be classified as large objects. These large objects are …

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Information on Bug#12704861 (which doesn’t exist in any public bug tracker)
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Some of you may be aware that MySQL is increasingly using an Oracle-internal bug tracker. You can see these large bug numbers mentioned alongside smaller public bug numbers in recent MySQL release notes. If you’re particularly unlucky, you  just get a big Oracle-internal bug number. For a recently fixed bug, I dug further, posted up on the Percona blog:

Possibly interesting reading for those of you who interested in InnoDB, MySQL, BLOBs and crash recovery.

Why a new memory engine may change everything ?
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I’m sure you are aware that the last Percona server release includes a new improved MEMORY storage engine for MySQL.
This new engine is based on Dynamic Row Format and offers some of great features, specialy for VARCHAR, VARBINARY, TEXT and BLOB fields in MEMORY tables.

But because this new MEMORY engine by Percona has some limitations and because Percona server …

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Understanding MySQL binary and non-binary string data types
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Having reviewed different table structures designed by different people, I have come to the conclusion that binary and non-binary string data types are used without consideration of the consequences of choosing either one. The confusion stems from the fact that both non-binary and binary string data appear to store characters because they can be saved as quoted string.

PBMS in Drizzle
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Some of you may have noticed that blob streaming has been merged into the main Drizzle tree recently. There are a few hooks inside the Drizzle kernel that PBMS uses, and everything else is just in the plug in.

For those not familiar with PBMS it does two things: provide a place (not in the table) for BLOBs to be stored (locally on disk or even out to S3) and provide a HTTP interface to get and store BLOBs.

This means you can do really neat things such as have your BLOBs replicated, consistent and all those nice databasey things as well as …

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BLOBS in the Drizzle/MySQL Storage Engine API
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Another (AFAIK) undocumented part of the Storage Engine API:

We all know what a normal row looks like in Drizzle/MySQL row format (a NULL bitmap and then column data):

Nothing that special. It’s a fixed sized buffer, Field objects reference into it, you read out of it and write the values into your engine. However, when you get to BLOBs, we can’t use a fixed sized buffer as BLOBs may be quite large. So, the format with BLOBS is the bit in the row is a length of the blob (1, 2, 3 or 4 bytes – in Drizzle …

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Dumping BLOBs the right way (UPDATED)
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I ran into a very interesting issue with a customer recently. The customer was storing JPEGs in MySQL (as BLOBs obviously) and was wanting to setup some additional MySQL slaves. Nothing crazy there. So I did the normal steps of scheduling a mysqldump with the --all-databases and --master-data options. Trouble is, the next day when I start importing the dump, 'mysql' bombed up with "ERROR at line X: Unknown command '\0'". I used 'sed' to pull out the lines around the error and didn't really notice anything out of the ordinary. After a bit of Googling, one suggestion was to do a simultaneous backup and restore (basically a "mysqldump .. | mysql -h ..."). In this case, …

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BLOB streaming, Raj Kissu, in the newspapers
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Raj Kissu is in the papers today. He completed a Google Summer of Code 2008 project with MySQL, hacking on blob streaming for phpMyAdmin. In fact, his project was so good, he has commit access to the phpMyAdmin tree :-)

Today, The Star had an article about him (and two other students), titled For the love of code. He said:

But Raj has already heard ­inquiries for his project. “A ­company that has developed a transactional engine using …

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Showing entries 1 to 10 of 16 6 Older Entries

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