Items tagged databases, sharding
Filters: databases × sharding × Sorted by date
How Figma’s databases team lived to tell the scale (via) The best kind of scaling war story:
"Figma’s database stack has grown almost 100x since 2020. [...] In 2020, we were running a single Postgres database hosted on AWS’s largest physical instance, and by the end of 2022, we had built out a distributed architecture with caching, read replicas, and a dozen vertically partitioned databases."
I like the concept of "colos", their internal name for sharded groups of related tables arranged such that those tables can be queried using joins.
Also smart: separating the migration into "logical sharding" - where queries all still run against a single database, even though they are logically routed as if the database was already sharded - followed by "physical sharding" where the data is actually copied to and served from the new database servers.
Logical sharding was implemented using PostgreSQL views, which can accept both reads and writes:
CREATE VIEW table_shard1 AS SELECT * FROM table
WHERE hash(shard_key) >= min_shard_range AND hash(shard_key) < max_shard_range)
The final piece of the puzzle was DBProxy, a custom PostgreSQL query proxy written in Go that can parse the query to an AST and use that to decide which shard the query should be sent to. Impressively it also has a scatter-gather mechanism, so select * from table can be sent to all shards at once and the results combined back together again. # 14th March 2024, 9:23 pm
Introducing Digg’s IDDB Infrastructure. IDDB is Digg’s new infrastructure component for sharding data across multiple databases, with support for both MySQL and memcachedb. “The DiggBar and URL minifying service is powered by a 16 machine IDDB cluster, which includes 8 write masters in the index and 8 MySQL storage nodes.” # 3rd April 2009, 8:42 pm
Database Sharding at Netlog, with MySQL and PHP. Detailed MySQL sharding case study from Netlog, who serve five billion page requests a month using thousands of shards across more than 80 database servers. # 2nd March 2009, 10:22 am
How FriendFeed uses MySQL to store schema-less data. The pain of altering/ adding indexes to tables with 250 million rows was killing their ability to try out new features, so they’ve moved to storing pickled Python objects and manually creating the indexes they need as denormalised two column tables. These can be created and dropped much more easily, and are continually populated by an off-line index building process. # 27th February 2009, 2:33 pm
Spock Proxy. A MySQL Proxy fork (no Lua) that concentrates solely on sharding, by parsing incoming SQL statements and redirecting them across multiple databases. There are some limitations on the SQL that can be handled (no nested queries, joins across a maximum of two tables) but generally it looks pretty impressive. # 11th December 2008, 9:49 am