* seastar fd29fd0...4d25b85 (2):
> core/file: fix EOF detection for file with custom impl
> tutorial: fix echo server example
Includes patch from Raphael updating checked_file_impl:
"Now file_impl requires dma_read_bulk to be implemented, and for
checked_file_impl, it only's about calling dma_read_bulk from
the posix file it wraps."
After resharding, sstables may be owned by all shards, which
means that file descriptors and memory usage for metadata will
increase by a factor equal to number of shards. That can easily
lead to OOM.
SSTable components are immutable, so they can be stored in one
shard and shared with others that need it. We use the following
formula to decide which shard will open the sstable and share
it with the others: (generation % smp::count), which is the
inverse of how we calculate generation for new sstables.
So if no resharding is performed, everything is shard-local.
With this approach, resource usage due to loaded sstables will
be evenly distributed among shards.
For this approach to work, we now only populate keyspaces from
shard 0. It's now the sole responsible for iterating through
column family dirs. In addition, most of population functions
are now free and take distributed database object as parameter.
Fixes#1951.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
By default, io checker will cause Scylla to shutdown if it finds
specific system errors. Right now, io checker isn't flexible
enough to allow a specialized handler. For example, we don't want
to Scylla to shutdown if there's an permission problem when
uploading new files from upload dir. This desired flexibility is
made possible here by allowing a handler parameter to io check
functions and also changing existing code to take advantage of it.
That's a step towards fixing #1709.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Inherit the alignment parameters from the underlying file instead of
defaulting to 4096. This gives better read performance on disks with 512-byte
sectors.
Fixes#1532.
Message-Id: <1470122188-25548-1-git-send-email-avi@scylladb.com>
