- Supporting multi-step, safe cut-over phase, where queries are blocked throughout the phase, and worst case scenario is table outage (no data corruption)
- Self-rollsback in case of failure (restored original table)
The idea is that the user is forced to specify the cut-over type they wish to use, given that each type has some drawbacks.
- More data in status hint
- `select count(*)` is deferred till after we validate migration is valid. Also, it is skipped on `--noop`
- Fixed version printing
- `rowCopyCompleteFlag` is a hint that allows us to escape the infinite loop of rowcopy once we are sure we have reached the end
- Operation would terminate after events lock noticed but before applying all events: race condition where the event would be captured asynchronously. The event is now handled sequentially with the DML events, hence now safe.
- Multiple rowcopy operations would still write to `rowCopyComplete` channel. This is still the case, but now we only wait for the first and then just flush (read and discard) any others, to avoid blocking
- Events DML listener is only added after table creation: the problem was that with very busy tables, the events func buffer would fill up, and the "tables-created" event would be blocked.
- `waitForEventsUpToLock()` unifies the waiting on all variants of complete-migration
- With `--test-on-replica`, now stopping replication "nicely", using `master_pos_wait()`
- With `--test-on-replica`, not throttling on replication after replication is stopped (duh)
- More debug output
- when `--test-on-replica`, the tested replica is implicitly a control replica
- added `replication-lag-query`, an alternate query to `SHOW SLAVE STATUS` to get replication lag
- throttling takes both the above into consideration
- Introduced `SwapTablesTimeoutSeconds`; `RENAME` is limited by this timeout
- If `RENAME` fails (due to the above), we throttle and retry
- `SwapTablesAtomic()` sets `lock_wait_timeout` and notifies with connection id
- `GrabVoluntaryLock()` intentionally grabs (and later releases) voluntary lock. It notifies when it is taken and awaits instructions as for when it could be released.
- `IssueBlockingQueryOnVoluntaryLock()` does what it says. It notifies with its connection_id so that it can be easily traced
- `stopWritesAndCompleteMigrationOnMasterViaLock()` does the thang. Oh dear this was agonizing and the code is a pain to look at, though under the limitations I do believe it is as clean as I could hope for.
- Added `switch-to-rbr` flag; applying binlog format change if needed
- Using dedicated db instance for locking & renaming on applier (must be used from within same connection)
- Heartbeat now uses `time.RFC3339Nano`
- Swap tables works! Caveat: short table outage
- `--test-on-replica` works!
- retries: using `panicAbort`: from any goroutine, regardless of context, it is possible to terminate the operation
- Reintroduced changelog events listener on streamer. This is the correct implementation.
- `INSERT`, `DELETE`, `UPDATE` statements
- support for `--noop`
- initial support for `--test-on-replica`. Verifying against `--allow-on-master`
- Changelog events no longer read from binlog stream, because reading it may be throttled, and we have to be able to keep reading the heartbeat and state events.
They are now being read directly from table, mapping already-seen-events to avoid confusion
Changlelog listener pools table in 2*frequency of heartbeat injection
- Throttling variables protected by mutex
- Added `--throttle-additional-flag-file`: `operation pauses when this file exists; hint: keep default, use for throttling multiple gh-osc operations`
- ColumnList is not a `struct` which contains ordinal mapping
- More implicit write changelog + audit changelog
- builder now builds `DELETE` and `INSERT` queries from data it will eventually get from DML event
- Sanity check for binlog_row_image
- Restarting replication to be sure binlog settings apply
- Prepare for accepting `SIGHUP` (reloading configuration)
- Supporting `--throttle-file-flag`
- Printing status
- Supporting transactional table syntax
- code cleanup; refactoring
- proper use of atomic where required
- iterations are in changelog (erm... maybe too much)
- `LOCK TABLES`, `UNLOCK TABLES` working
- Using heartbeat
- Throttling works based on heartbeat
- Refactored binlog_reader stuff. Now streaming events (into golang channel, which makes for nice buffering and throttling)
- Binlog table listeners work
- More Migrator logic; existing logic for waiting on `state` events (e.g. `TablesCreatedState`)
