6 ms·

Can you expand on what you mean by a single table with manual indexes? How does a frequently used table with indexes not resemble an RDBMS?

Illniyar 10y ago
the secondary indexes are saved in a different table and (I can only assume) the application layer (or one layer above mySql) is responsible for keeping that table up to date. If you use only 1 table, then it's by no means "relational", so I don't see why you'll need a database system designed from start to finish to support a relational model.
- pas 10y ago
  The "relationalness" is/was not really important here. It's all about MVCC and how storage engines handle it. Postgres is lacking in these scenarios, whereas a particular fine tuned version (or fork) of InnoDB (or MyRocks or whatever they end up chosing) handles this better. See Facebook's "mysql-5.6" branch, that has hundreds of patches piled on to support especially these taxing workloads.
  - Illniyar 10y ago
    Well, for that matter, as I understood it, they also have no transactions nor atomicity and are basically eventually consistant , though these I'm simply inferring from their posts, it was not stated as far as I can remember. So MVCC also has almost zero bearing on what they are doing.
    - spotman 10y ago
      Just because you may not always use the database with the BEGIN/COMMIT semantics, that absolutely does not mean that "MVCC has almost no bearing on what they are doing". MVCC and how it has been implemented in the two storage engines in discussion here absolutely has a lot to do with it.
- laszlokorte 10y ago
  > If you use only 1 table, then it's by no means "relational" [...] FYI The term "relational" in "relational database" does not refer to the relation between tables but to the mathematical concept of a relation which is some set of tuples ie a single table.
  - Illniyar 10y ago
    Well, the relational model does not describe or contain a notion of table really, so I guess you could model it in any way you want, even within a single table. But I think that's a mute point, I doubt they kept any part of the relational model inside their schemaless database.
    - slavik81 10y ago
      Probably just an auto-correct mistake, but you mean "that's a moot point".
      - hinkley 10y ago
        Autocorrect, don't take it for granite.
- deleted 10y ago
  [deleted]

Illniyar 10y ago

the secondary indexes are saved in a different table and (I can only assume) the application layer (or one layer above mySql) is responsible for keeping that table up to date. If you use only 1 table, then it's by no means "relational", so I don't see why you'll need a database system designed from start to finish to support a relational model.

pas 10y ago
The "relationalness" is/was not really important here. It's all about MVCC and how storage engines handle it. Postgres is lacking in these scenarios, whereas a particular fine tuned version (or fork) of InnoDB (or MyRocks or whatever they end up chosing) handles this better. See Facebook's "mysql-5.6" branch, that has hundreds of patches piled on to support especially these taxing workloads.
- Illniyar 10y ago
  Well, for that matter, as I understood it, they also have no transactions nor atomicity and are basically eventually consistant , though these I'm simply inferring from their posts, it was not stated as far as I can remember. So MVCC also has almost zero bearing on what they are doing.
  - spotman 10y ago
    Just because you may not always use the database with the BEGIN/COMMIT semantics, that absolutely does not mean that "MVCC has almost no bearing on what they are doing". MVCC and how it has been implemented in the two storage engines in discussion here absolutely has a lot to do with it.
laszlokorte 10y ago
> If you use only 1 table, then it's by no means "relational" [...] FYI The term "relational" in "relational database" does not refer to the relation between tables but to the mathematical concept of a relation which is some set of tuples ie a single table.
- Illniyar 10y ago
  Well, the relational model does not describe or contain a notion of table really, so I guess you could model it in any way you want, even within a single table. But I think that's a mute point, I doubt they kept any part of the relational model inside their schemaless database.
  - slavik81 10y ago
    Probably just an auto-correct mistake, but you mean "that's a moot point".
    - hinkley 10y ago
      Autocorrect, don't take it for granite.
deleted 10y ago
[deleted]