This commit reverts 4e469f8 which was used for debugging the validation
stall corruption issue. It can cause the disk to fill with temporary
files though so it is being reverted.
This commit fixes a timing bug that occurs in a specific scenario
where the shadow wal sync stalls because of an s3 validation and
the catch up write to the shadow wal is large enough to allow a
window between WAL reads and the final copy.
The file copy has been replaced by direct writes of the frame
buffer to the shadow to ensure that every validated byte is exactly
what is being written to the shadow wal. The one downside to this
change is that the frame buffer will grow with the transaction
size so it will use additional heap. This can be replaced by a
spill-to-disk implementation but this should work well in the
short term.
This commit sets a hard upper limit for the WAL index to (1<<31)-1.
The index is hex-encoded in file names as a 4-byte unsigned integer
so limit ensures all index values are below any upper limit and are
unaffected by any signed int limit.
A WAL file is typically at least 4MB so you would need to write
8 petabytes to reach this upper limit.
Currently, the WAL copy function can encounter a checksum mismatch in a
WAL frame and it will return an error. This can occur for partial writes
and is recovered from moments later. This commit changes the error to a
log write instead.
Previously, there were excessive log messages for checkpoints and
retention. These have been removed or combined into a single log
message where appropriate.
This commit refactors the commands to allow a replica URL when
restoring a database. If the first CLI arg is a URL with a scheme,
the it is treated as a replica URL.
Previously, the sync would validate the last page written to ensure
that replication picked up from the last position. However, a large
WAL file followed by a series of shorter checkpointed WAL files means
that the last page could be the same even if multiple checkpoints
have occurred.
To fix this, the WAL header must match the shadow WAL header when
starting litestream since there are no guarantees about checkpoints.
