2018-03-05 1:42 GMT-08:00 Aleksander Alekseev <a.aleks...@postgrespro.ru>:
> Hello Charles, > > > Went through the documents listed by you, and they are helpful! > > It seems the main purpose of extension pg_protobuf is to parse > > a protobuf struct and return the decoded field. May I ask how these kinds > > of extensions are used in postgreSQL (or in other words, the scenarios to > > use these plugins)? > > There are a few ideas behind all of this. > > 1) Sometimes people are not quite happy with strict relational schema by > various reasons and prefer something more agile, like XML or JSON. These > formats are indeed more convenient under certain circumstances, for > instance in terms of ease of changing and migrating the schema. > > 2) One drawback of JSON is redundancy. For instance, you have to store > the names of all document fields. These names don't carry much > information but consume disk space and RAM thus affecting the overall > performance. ZSON extension [1] partially solved this issue. However I > wouldn't call it particularly convenient and the whole approach of > compressing JSON seems to me more like a dirty hack, not a solution. The > problem appeared because of using the wrong data format in the first > place. > > 3) Unlike JSON, formats like Protobuf or Thrift are binary formats and > most importantly don't store any field names. Thus they don't create a > problem described above. However, PostgreSQL is not capable to access > Protobuf fields out-of-the-box, for instance to index these fields. This > is what pg_protobuf is for. > > The idea of using flexible schema and build index on top of them is awesome! Will definitely submit a proposal and focus on this if get selected. Thanks for answering my questions. > Hopefully this answers you question. If you have other questions please > don't hesitate to ask! > > [1]: https://github.com/postgrespro/zson > > > -- > Best regards, > Aleksander Alekseev >
