gavinchou opened a new pull request, #39123:
URL: https://github.com/apache/doris/pull/39123
Session variable `disable_file_cache` is processed as "disposable file
cache" in beta_rowset_reader.cpp.
```
if (_read_context->runtime_state != nullptr) {
_read_options.io_ctx.query_id =
&_read_context->runtime_state->query_id();
_read_options.io_ctx.read_file_cache =
_read_context->runtime_state->query_options().enable_file_cache;
_read_options.io_ctx.is_disposable =
_read_context->runtime_state->query_options().disable_file_cache;
}
```
We use disposable cache to avoid IO amp and avoid large amount of eviction
from the cached data ("normal cache").
We cannot set the read option cache policy to "no cache" because it may
cause IO amp: every page IO will cause a remote IO, which is a performance
disaster.
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