It would be better to not update xl_crc/rec_hdr at all when skipping contrecord,
but I would prefer to keep PR #1574 small.
Better audit of `find_end_of_wal_segment` is coming anyway in #544.
Previous invariant: `crc` contains an "unfinalized" CRC32 value,
its one complement, like in postgres before FIN_CRC32C.
New invariant: `crc` always contains a "finalized" CRC32 value,
this is the semantics of crc32c_append, so we don't need to invert CRC manually.
* Actual generation logic is in a separate crate `postgres_ffi/wal_generate`
* The create also provides a binary for debug purposes akin to `initdb`
* Two tests currently fail and are ignored
* There is no easy way to test this directly in Safekeeper as it starts restoring from commit_lsn.
So testing would require disconnecting Safekeeper just after it has received the WAL,
but before it is committed.
* Do not set LSN for new FPI page
refer #1656
* Add page_is_new, page_get_lsn, page_set_lsn functions
* Fix page_is_new implementation
* Add comment from XLogReadBufferForRedoExtended
A new `get_lsn_by_timestamp` command is added to the libpq page service
API.
An extra timestamp field is now stored in an extra field after each
Clog page. It is the timestamp of the latest commit, among all the
transactions on the Clog page. To find the overall latest commit, we
need to scan all Clog pages, but this isn't a very frequent operation
so that's not too bad.
To find the LSN that corresponds to a timestamp, we perform a binary
search. The binary search starts with min = last LSN when GC ran, and
max = latest LSN on the timeline. On each iteration of the search we
check if there are any commits with a higher-than-requested timestamp
at that LSN.
Implements github issue 1361.
Commit edba2e97 renamed pageserver/README to pageserver/README.md, but
forgot to update links to it. Fix.
Rename libs/postgres_ffi/README and safekeeper/README files to also
have the the .md extension, so that github can render them nicely.
Quote ascii-diagram in safekeeper/README.md so that it renders
correctly.
