Remove outdated documentation

docs/en/development/architecture.md

@@ -49,27 +49,13 @@ When we calculate some function over columns in a block, we add another column w
 
 Blocks are created for every processed chunk of data. Note that for the same type of calculation, the column names and types remain the same for different blocks, and only column data changes. It is better to split block data from the block header because small block sizes have a high overhead of temporary strings for copying shared_ptrs and column names.
 
-## Block Streams {#block-streams}
+## Processors
 
-Block streams are for processing data. We use streams of blocks to read data from somewhere, perform data transformations, or write data to somewhere. `IBlockInputStream` has the `read` method to fetch the next block while available. `IBlockOutputStream` has the `write` method to push the block somewhere.
-
-Streams are responsible for:
-
-1.  Reading or writing to a table. The table just returns a stream for reading or writing blocks.
-2.  Implementing data formats. For example, if you want to output data to a terminal in `Pretty` format, you create a block output stream where you push blocks, and it formats them.
-3.  Performing data transformations. Let’s say you have `IBlockInputStream` and want to create a filtered stream. You create `FilterBlockInputStream` and initialize it with your stream. Then when you pull a block from `FilterBlockInputStream`, it pulls a block from your stream, filters it, and returns the filtered block to you. Query execution pipelines are represented this way.
-
-There are more sophisticated transformations. For example, when you pull from `AggregatingBlockInputStream`, it reads all data from its source, aggregates it, and then returns a stream of aggregated data for you. Another example: `UnionBlockInputStream` accepts many input sources in the constructor and also a number of threads. It launches multiple threads and reads from multiple sources in parallel.
-
-> Block streams use the “pull” approach to control flow: when you pull a block from the first stream, it consequently pulls the required blocks from nested streams, and the entire execution pipeline will work. Neither “pull” nor “push” is the best solution, because control flow is implicit, and that limits the implementation of various features like simultaneous execution of multiple queries (merging many pipelines together). This limitation could be overcome with coroutines or just running extra threads that wait for each other. We may have more possibilities if we make control flow explicit: if we locate the logic for passing data from one calculation unit to another outside of those calculation units. Read this [article](http://journal.stuffwithstuff.com/2013/01/13/iteration-inside-and-out/) for more thoughts.
-
-We should note that the query execution pipeline creates temporary data at each step. We try to keep block size small enough so that temporary data fits in the CPU cache. With that assumption, writing and reading temporary data is almost free in comparison with other calculations. We could consider an alternative, which is to fuse many operations in the pipeline together. It could make the pipeline as short as possible and remove much of the temporary data, which could be an advantage, but it also has drawbacks. For example, a split pipeline makes it easy to implement caching intermediate data, stealing intermediate data from similar queries running at the same time, and merging pipelines for similar queries.
+See the description at [https://github.com/ClickHouse/ClickHouse/blob/master/src/Processors/IProcessor.h](https://github.com/ClickHouse/ClickHouse/blob/master/src/Processors/IProcessor.h).
 
 ## Formats {#formats}
 
-Data formats are implemented with block streams. There are “presentational” formats only suitable for the output of data to the client, such as `Pretty` format, which provides only `IBlockOutputStream`. And there are input/output formats, such as `TabSeparated` or `JSONEachRow`.
-
-There are also row streams: `IRowInputStream` and `IRowOutputStream`. They allow you to pull/push data by individual rows, not by blocks. And they are only needed to simplify the implementation of row-oriented formats. The wrappers `BlockInputStreamFromRowInputStream` and `BlockOutputStreamFromRowOutputStream` allow you to convert row-oriented streams to regular block-oriented streams.
+Data formats are implemented with processors.
 
 ## I/O {#io}