Server settings:
- max_local_read_bandwidth_for_server
- max_local_write_bandwidth_for_server
Query settings:
- max_local_read_bandwidth
- max_local_write_bandwidth
This is the preparation for adding ability to throttle BACKUPs
Signed-off-by: Azat Khuzhin <a.khuzhin@semrush.com>
Right now streams relies on correct file size not the number of bytes
that will be read from the stream, to overcome one bug in the linux
kernel that may return EIINVAL for pread() with offset pass the EOF.
v2: Swap read_hint and file_size (since it is easy to miss something)
Before the first argument to readFile()/createReadBufferFromFileBase()
was read_hint, not the file_size, and let's preserve the order, since
it is easy to miss something
This will also fix 02051_read_settings test automatically because now
MergeTreeReaderStream will pass estimated_sum_mark_range_bytes to
read_hint not file_size, previously it cause on of the following errors:
- Attempt to read after EOF w/ O_DIRECT
- and LOGICAL_ERROR while adjusting granulas w/o O_DIRECT
This will also improve zero-length reads guard (via
ReadBufferFromEmptyFile), that had been added in #30190
v3: fix for other storages that wasn't enabled in fast-test
v4: ignore ENOENT/ENOTSUP in readFile
