jiacai2050 commented on issue #1600:
URL: https://github.com/apache/horaedb/issues/1600#issuecomment-2506900473

   Those are all great questions, 
   1. We use `version` field to deal with schema  evolution, if we want to add 
some fields to manifest, a new version could be added, and when merge, to 
convert old manifest to new one.
   2. Object store don't have the append interface, so append here means 
download the old one into memory, then merge with new delta manifests, then 
upload it again to overwrite the old one.
   3. There shouldn't many manifest files, we have a hard limit on how many 
delta files a manifest can have, if there are more than that, the write process 
will fail, only after the merge process is finished, we can allow creating new 
manifest deltas.
   
   As for the third question, that why we need to keep metadata of each sst 
small, so we can hold millions of sst files in one manifest snapshot, whose 
size is less than 1GB.
   
   ``` shell
   1024*1024*1024 / 28 (size of each sst's metadata) = 38347922
   ```


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