-test-on-replica: errors on 'replication not running' then on 'cut-over failure' then on 'table already exist'

v1.0.36, this is repeatable. seemingly a successful test migration that just did ALTER TABLE x ROW_FORMAT=COMPACT. However the output has some troublesome messages:

```

2017-04-24 18:12:35 DEBUG Iteration complete: no further range to iterate
2017-04-24 18:12:35 INFO Row copy complete
2017-04-24 18:12:35 DEBUG Iteration complete: no further range to iterate
2017-04-24 18:12:35 DEBUG Getting nothing in the write queue. Sleeping...
2017-04-24 18:12:35 DEBUG checking for cut-over postpone
2017-04-24 18:12:35 DEBUG checking for cut-over postpone: complete
2017-04-24 18:12:35 DEBUG testing on replica. Stopping replication IO thread
Copy: 19058539/19058539 100.0%; Applied: 61434; Backlog: 0/100; Time: 2h35m0s(total), 2h34m29s(copy); streamer: binlog.037230:557720; State: migrating; ETA: due
2017-04-24 18:12:35 INFO Stopping replication IO thread
2017-04-24 18:12:36 INFO Replication IO thread stopped
2017-04-24 18:12:36 INFO Verifying SQL thread is stopped
2017-04-24 18:12:36 DEBUG Getting nothing in the write queue. Sleeping...
2017-04-24 18:12:36 ERROR replication not running; Slave_IO_Running=No, Slave_SQL_Running=Yes
goroutine 257227 [running]:
runtime/debug.Stack(0x5d, 0x43, 0x0)
/usr/lib64/go/src/runtime/debug/stack.go:24 +0x79
runtime/debug.PrintStack()
/usr/lib64/go/src/runtime/debug/stack.go:16 +0x22
github.com/github/gh-ost/vendor/github.com/outbrain/golib/log.logErrorEntry(0x2, 0x8fcce0, 0xc427b20fd0, 0x60d9d0, 0xc4204acf88)
/builddir/build/BUILD/gh-ost-v1.0.36-1_f693aeede4fa.el7/gopath/src/github.com/github/gh-ost/vendor/github.com/outbrain/golib/log/log.go:178 +0xfd
github.com/github/gh-ost/vendor/github.com/outbrain/golib/log.Errore(0x8fcce0, 0xc427b20fd0, 0x8fcce0, 0xc427b20fd0)
/builddir/build/BUILD/gh-ost-v1.0.36-1_f693aeede4fa.el7/gopath/src/github.com/github/gh-ost/vendor/github.com/outbrain/golib/log/log.go:224 +0x3e
github.com/github/gh-ost/go/logic.(*Throttler).collectReplicationLag.func1(0xc4206ad7a8, 0x1)
/builddir/build/BUILD/gh-ost-v1.0.36-1_f693aeede4fa.el7/gopath/src/github.com/github/gh-ost/go/logic/throttler.go:105 +0xa8
created by github.com/github/gh-ost/go/logic.(*Throttler).collectReplicationLag
/builddir/build/BUILD/gh-ost-v1.0.36-1_f693aeede4fa.el7/gopath/src/github.com/github/gh-ost/go/logic/throttler.go:124 +0x12b
2017-04-24 18:12:36 ERROR replication not running; Slave_IO_Running=No, Slave_SQL_Running=No
goroutine 257845 [running]:
runtime/debug.Stack(0x5c, 0x42, 0x0)
/usr/lib64/go/src/runtime/debug/stack.go:24 +0x79
runtime/debug.PrintStack()
/usr/lib64/go/src/runtime/debug/stack.go:16 +0x22
github.com/github/gh-ost/vendor/github.com/outbrain/golib/log.logErrorEntry(0x2, 0x8fcce0, 0xc42a2e4380, 0x60d9d0, 0xc422887f88)
/builddir/build/BUILD/gh-ost-v1.0.36-1_f693aeede4fa.el7/gopath/src/github.com/github/gh-ost/vendor/github.com/outbrain/golib/log/log.go:178 +0xfd
github.com/github/gh-ost/vendor/github.com/outbrain/golib/log.Errore(0x8fcce0, 0xc42a2e4380, 0x8fcce0, 0xc42a2e4380)
/builddir/build/BUILD/gh-ost-v1.0.36-1_f693aeede4fa.el7/gopath/src/github.com/github/gh-ost/vendor/github.com/outbrain/golib/log/log.go:224 +0x3e
github.com/github/gh-ost/go/logic.(*Throttler).collectReplicationLag.func1(0xc4206ad7a8, 0x1)
/builddir/build/BUILD/gh-ost-v1.0.36-1_f693aeede4fa.el7/gopath/src/github.com/github/gh-ost/go/logic/throttler.go:105 +0xa8
created by github.com/github/gh-ost/go/logic.(*Throttler).collectReplicationLag
/builddir/build/BUILD/gh-ost-v1.0.36-1_f693aeede4fa.el7/gopath/src/github.com/github/gh-ost/go/logic/throttler.go:124 +0x12b

... more like this ... but then:

```

```

2017-04-24 18:13:17 ERROR Error 1050: Table '_TableName_gho' already exists
goroutine 1 [running]:
runtime/debug.Stack(0x5a, 0x40, 0x0)
/usr/lib64/go/src/runtime/debug/stack.go:24 +0x79
runtime/debug.PrintStack()
/usr/lib64/go/src/runtime/debug/stack.go:16 +0x22
github.com/github/gh-ost/vendor/github.com/outbrain/golib/log.logErrorEntry(0x2, 0x8fcda0, 0xc4202364a0, 0x8fcda0, 0xc4202364a0)
/builddir/build/BUILD/gh-ost-v1.0.36-1_f693aeede4fa.el7/gopath/src/github.com/github/gh-ost/vendor/github.com/outbrain/golib/log/log.go:178 +0xfd
github.com/github/gh-ost/vendor/github.com/outbrain/golib/log.Errore(0x8fcda0, 0xc4202364a0, 0xae, 0x0)
/builddir/build/BUILD/gh-ost-v1.0.36-1_f693aeede4fa.el7/gopath/src/github.com/github/gh-ost/vendor/github.com/outbrain/golib/log/log.go:224 +0x3e
github.com/github/gh-ost/vendor/github.com/outbrain/golib/sqlutils.ExecNoPrepare(0xc4200b9180, 0xc4200f82c0, 0xae, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0)
/builddir/build/BUILD/gh-ost-v1.0.36-1_f693aeede4fa.el7/gopath/src/github.com/github/gh-ost/vendor/github.com/outbrain/golib/sqlutils/sqlutils.go:283 +0x154
Copy: 19058539/19058539 100.0%; Applied: 90780; Backlog: 13/100; Time: 2h43m15s(total), 2h34m29s(copy); streamer: binlog.037259:72140140; State: throttled, lag=2.000000s; ETA: due
github.com/github/gh-ost/go/logic.(*Applier).RenameTablesRollback(0xc42018ab40, 0x708b80, 0xc42a33e3e0)
/builddir/build/BUILD/gh-ost-v1.0.36-1_f693aeede4fa.el7/gopath/src/github.com/github/gh-ost/go/logic/applier.go:564 +0x4be
github.com/github/gh-ost/go/logic.(*Migrator).handleCutOverResult(0xc42009c480, 0x8fcce0, 0xc420015610, 0x0, 0x0)
/builddir/build/BUILD/gh-ost-v1.0.36-1_f693aeede4fa.el7/gopath/src/github.com/github/gh-ost/go/logic/migrator.go:391 +0x202
github.com/github/gh-ost/go/logic.(*Migrator).cutOver(0xc42009c480, 0x2, 0xc4205d2480)
/builddir/build/BUILD/gh-ost-v1.0.36-1_f693aeede4fa.el7/gopath/src/github.com/github/gh-ost/go/logic/migrator.go:479 +0x2cb
github.com/github/gh-ost/go/logic.(*Migrator).(github.com/github/gh-ost/go/logic.cutOver)-fm(0x3b9aca00, 0xc429564120)
/builddir/build/BUILD/gh-ost-v1.0.36-1_f693aeede4fa.el7/gopath/src/github.com/github/gh-ost/go/logic/migrator.go:367 +0x2a
github.com/github/gh-ost/go/logic.(*Migrator).retryOperation(0xc42009c480, 0xc4205e3c90, 0x0, 0x0, 0x0, 0xc428925c50, 0x2a)
/builddir/build/BUILD/gh-ost-v1.0.36-1_f693aeede4fa.el7/gopath/src/github.com/github/gh-ost/go/logic/migrator.go:158 +0x67
github.com/github/gh-ost/go/logic.(*Migrator).Migrate(0xc42009c480, 0x0, 0x0)
/builddir/build/BUILD/gh-ost-v1.0.36-1_f693aeede4fa.el7/gopath/src/github.com/github/gh-ost/go/logic/migrator.go:367 +0x7e7
main.main()
/builddir/build/BUILD/gh-ost-v1.0.36-1_f693aeede4fa.el7/gopath/src/github.com/github/gh-ost/go/cmd/gh-ost/main.go:243 +0x1bec
2017-04-24 18:13:17 INFO Renaming back to ghost table
2017-04-24 18:13:17 ERROR Error 1050: Table '_TableName_gho' already exists
goroutine 1 [running]:
runtime/debug.Stack(0x5a, 0x40, 0x0)
/usr/lib64/go/src/runtime/debug/stack.go:24 +0x79
runtime/debug.PrintStack()
/usr/lib64/go/src/runtime/debug/stack.go:16 +0x22
github.com/github/gh-ost/vendor/github.com/outbrain/golib/log.logErrorEntry(0x2, 0x8fcda0, 0xc4202365a0, 0x8fcda0, 0xc4202365a0)
/builddir/build/BUILD/gh-ost-v1.0.36-1_f693aeede4fa.el7/gopath/src/github.com/github/gh-ost/vendor/github.com/outbrain/golib/log/log.go:178 +0xfd
github.com/github/gh-ost/vendor/github.com/outbrain/golib/log.Errore(0x8fcda0, 0xc4202365a0, 0x63, 0x0)
/builddir/build/BUILD/gh-ost-v1.0.36-1_f693aeede4fa.el7/gopath/src/github.com/github/gh-ost/vendor/github.com/outbrain/golib/log/log.go:224 +0x3e
github.com/github/gh-ost/vendor/github.com/outbrain/golib/sqlutils.ExecNoPrepare(0xc4200b9180, 0xc4200782a0, 0x63, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0)
/builddir/build/BUILD/gh-ost-v1.0.36-1_f693aeede4fa.el7/gopath/src/github.com/github/gh-ost/vendor/github.com/outbrain/golib/sqlutils/sqlutils.go:283 +0x154
github.com/github/gh-ost/go/logic.(*Applier).RenameTablesRollback(0xc42018ab40, 0x708b80, 0xc42a33e3e0)
/builddir/build/BUILD/gh-ost-v1.0.36-1_f693aeede4fa.el7/gopath/src/github.com/github/gh-ost/go/logic/applier.go:575 +0x783
github.com/github/gh-ost/go/logic.(*Migrator).handleCutOverResult(0xc42009c480, 0x8fcce0, 0xc420015610, 0x0, 0x0)
/builddir/build/BUILD/gh-ost-v1.0.36-1_f693aeede4fa.el7/gopath/src/github.com/github/gh-ost/go/logic/migrator.go:391 +0x202
github.com/github/gh-ost/go/logic.(*Migrator).cutOver(0xc42009c480, 0x2, 0xc4205d2480)
/builddir/build/BUILD/gh-ost-v1.0.36-1_f693aeede4fa.el7/gopath/src/github.com/github/gh-ost/go/logic/migrator.go:479 +0x2cb
github.com/github/gh-ost/go/logic.(*Migrator).(github.com/github/gh-ost/go/logic.cutOver)-fm(0x3b9aca00, 0xc429564120)
/builddir/build/BUILD/gh-ost-v1.0.36-1_f693aeede4fa.el7/gopath/src/github.com/github/gh-ost/go/logic/migrator.go:367 +0x2a
github.com/github/gh-ost/go/logic.(*Migrator).retryOperation(0xc42009c480, 0xc4205e3c90, 0x0, 0x0, 0x0, 0xc428925c50, 0x2a)
/builddir/build/BUILD/gh-ost-v1.0.36-1_f693aeede4fa.el7/gopath/src/github.com/github/gh-ost/go/logic/migrator.go:158 +0x67
github.com/github/gh-ost/go/logic.(*Migrator).Migrate(0xc42009c480, 0x0, 0x0)
/builddir/build/BUILD/gh-ost-v1.0.36-1_f693aeede4fa.el7/gopath/src/github.com/github/gh-ost/go/logic/migrator.go:367 +0x7e7
main.main()
/builddir/build/BUILD/gh-ost-v1.0.36-1_f693aeede4fa.el7/gopath/src/github.com/github/gh-ost/go/cmd/gh-ost/main.go:243 +0x1bec
2017-04-24 18:13:17 INFO Renaming back to original table
2017-04-24 18:13:17 ERROR Error 1050: Table 'TableName' already exists
goroutine 1 [running]:
runtime/debug.Stack(0x55, 0x3b, 0x0)
/usr/lib64/go/src/runtime/debug/stack.go:24 +0x79
runtime/debug.PrintStack()
/usr/lib64/go/src/runtime/debug/stack.go:16 +0x22
github.com/github/gh-ost/vendor/github.com/outbrain/golib/log.logErrorEntry(0x2, 0x8fcda0, 0xc420236680, 0x8fcda0, 0xc420236680)
/builddir/build/BUILD/gh-ost-v1.0.36-1_f693aeede4fa.el7/gopath/src/github.com/github/gh-ost/vendor/github.com/outbrain/golib/log/log.go:178 +0xfd
github.com/github/gh-ost/vendor/github.com/outbrain/golib/log.Errore(0x8fcda0, 0xc420236680, 0x63, 0x0)
/builddir/build/BUILD/gh-ost-v1.0.36-1_f693aeede4fa.el7/gopath/src/github.com/github/gh-ost/vendor/github.com/outbrain/golib/log/log.go:224 +0x3e
github.com/github/gh-ost/vendor/github.com/outbrain/golib/sqlutils.ExecNoPrepare(0xc4200b9180, 0xc420078310, 0x63, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0)
/builddir/build/BUILD/gh-ost-v1.0.36-1_f693aeede4fa.el7/gopath/src/github.com/github/gh-ost/vendor/github.com/outbrain/golib/sqlutils/sqlutils.go:283 +0x154
github.com/github/gh-ost/go/logic.(*Applier).RenameTablesRollback(0xc42018ab40, 0x708b80, 0xc42a33e3e0)
Copy: 19058539/19058539 100.0%; Applied: 90780; Backlog: 0/100; Time: 2h43m20s(total), 2h34m29s(copy); streamer: binlog.037259:94763393; State: throttled, lag=3.000000s; ETA: due
/builddir/build/BUILD/gh-ost-v1.0.36-1_f693aeede4fa.el7/gopath/src/github.com/github/gh-ost/go/logic/applier.go:585 +0xa4e
github.com/github/gh-ost/go/logic.(*Migrator).handleCutOverResult(0xc42009c480, 0x8fcce0, 0xc420015610, 0x0, 0x0)
/builddir/build/BUILD/gh-ost-v1.0.36-1_f693aeede4fa.el7/gopath/src/github.com/github/gh-ost/go/logic/migrator.go:391 +0x202
github.com/github/gh-ost/go/logic.(*Migrator).cutOver(0xc42009c480, 0x2, 0xc4205d2480)
/builddir/build/BUILD/gh-ost-v1.0.36-1_f693aeede4fa.el7/gopath/src/github.com/github/gh-ost/go/logic/migrator.go:479 +0x2cb
github.com/github/gh-ost/go/logic.(*Migrator).(github.com/github/gh-ost/go/logic.cutOver)-fm(0x3b9aca00, 0xc429564120)
/builddir/build/BUILD/gh-ost-v1.0.36-1_f693aeede4fa.el7/gopath/src/github.com/github/gh-ost/go/logic/migrator.go:367 +0x2a
github.com/github/gh-ost/go/logic.(*Migrator).retryOperation(0xc42009c480, 0xc4205e3c90, 0x0, 0x0, 0x0, 0xc428925c50, 0x2a)
/builddir/build/BUILD/gh-ost-v1.0.36-1_f693aeede4fa.el7/gopath/src/github.com/github/gh-ost/go/logic/migrator.go:158 +0x67
github.com/github/gh-ost/go/logic.(*Migrator).Migrate(0xc42009c480, 0x0, 0x0)
/builddir/build/BUILD/gh-ost-v1.0.36-1_f693aeede4fa.el7/gopath/src/github.com/github/gh-ost/go/logic/migrator.go:367 +0x7e7
main.main()
/builddir/build/BUILD/gh-ost-v1.0.36-1_f693aeede4fa.el7/gopath/src/github.com/github/gh-ost/go/cmd/gh-ost/main.go:243 +0x1bec
2017-04-24 18:13:17 ERROR Error 1050: Table 'TableName' already exists
goroutine 1 [running]:
runtime/debug.Stack(0x55, 0x3b, 0x0)
/usr/lib64/go/src/runtime/debug/stack.go:24 +0x79
runtime/debug.PrintStack()
/usr/lib64/go/src/runtime/debug/stack.go:16 +0x22
github.com/github/gh-ost/vendor/github.com/outbrain/golib/log.logErrorEntry(0x2, 0x8fcda0, 0xc420236680, 0x8fcda0, 0xc420236680)
/builddir/build/BUILD/gh-ost-v1.0.36-1_f693aeede4fa.el7/gopath/src/github.com/github/gh-ost/vendor/github.com/outbrain/golib/log/log.go:178 +0xfd
github.com/github/gh-ost/vendor/github.com/outbrain/golib/log.Errore(0x8fcda0, 0xc420236680, 0x63, 0x0)
/builddir/build/BUILD/gh-ost-v1.0.36-1_f693aeede4fa.el7/gopath/src/github.com/github/gh-ost/vendor/github.com/outbrain/golib/log/log.go:224 +0x3e
github.com/github/gh-ost/go/logic.(*Applier).RenameTablesRollback(0xc42018ab40, 0x708b80, 0xc42a33e3e0)
/builddir/build/BUILD/gh-ost-v1.0.36-1_f693aeede4fa.el7/gopath/src/github.com/github/gh-ost/go/logic/applier.go:588 +0xa6b
github.com/github/gh-ost/go/logic.(*Migrator).handleCutOverResult(0xc42009c480, 0x8fcce0, 0xc420015610, 0x0, 0x0)
/builddir/build/BUILD/gh-ost-v1.0.36-1_f693aeede4fa.el7/gopath/src/github.com/github/gh-ost/go/logic/migrator.go:391 +0x202
github.com/github/gh-ost/go/logic.(*Migrator).cutOver(0xc42009c480, 0x2, 0xc4205d2480)
/builddir/build/BUILD/gh-ost-v1.0.36-1_f693aeede4fa.el7/gopath/src/github.com/github/gh-ost/go/logic/migrator.go:479 +0x2cb
github.com/github/gh-ost/go/logic.(*Migrator).(github.com/github/gh-ost/go/logic.cutOver)-fm(0x3b9aca00, 0xc429564120)
/builddir/build/BUILD/gh-ost-v1.0.36-1_f693aeede4fa.el7/gopath/src/github.com/github/gh-ost/go/logic/migrator.go:367 +0x2a
github.com/github/gh-ost/go/logic.(*Migrator).retryOperation(0xc42009c480, 0xc4205e3c90, 0x0, 0x0, 0x0, 0xc428925c50, 0x2a)
/builddir/build/BUILD/gh-ost-v1.0.36-1_f693aeede4fa.el7/gopath/src/github.com/github/gh-ost/go/logic/migrator.go:158 +0x67
github.com/github/gh-ost/go/logic.(*Migrator).Migrate(0xc42009c480, 0x0, 0x0)
/builddir/build/BUILD/gh-ost-v1.0.36-1_f693aeede4fa.el7/gopath/src/github.com/github/gh-ost/go/logic/migrator.go:367 +0x7e7
main.main()
/builddir/build/BUILD/gh-ost-v1.0.36-1_f693aeede4fa.el7/gopath/src/github.com/github/gh-ost/go/cmd/gh-ost/main.go:243 +0x1bec
.... more like this
```

now it stops complaining about replication not running and says the cutover has failed.
What follows is the tail of the log.

```
2017-04-24 18:13:17 DEBUG testing on replica. Starting replication IO thread after cut-over failure
2017-04-24 18:13:17 INFO Starting replication IO thread
2017-04-24 18:13:17 INFO Replication IO thread started
2017-04-24 18:13:17 INFO Verifying SQL thread is running
2017-04-24 18:13:17 INFO SQL thread started
2017-04-24 18:13:17 INFO Replication started
2017-04-24 18:13:18 DEBUG throttling before swapping tables
Copy: 19058539/19058539 100.0%; Applied: 90780; Backlog: 1/100; Time: 2h43m25s(total), 2h34m29s(copy); streamer: binlog.037260:13486064; State: migrating; ETA: due
2017-04-24 18:13:18 DEBUG throttling before swapping tables
2017-04-24 18:13:18 DEBUG throttling before swapping tables
2017-04-24 18:13:19 DEBUG throttling before swapping tables
2017-04-24 18:13:19 DEBUG throttling before swapping tables
2017-04-24 18:13:19 DEBUG throttling before swapping tables
2017-04-24 18:13:19 DEBUG throttling before swapping tables
2017-04-24 18:13:20 DEBUG throttling before swapping tables
2017-04-24 18:13:20 DEBUG throttling before swapping tables
2017-04-24 18:13:20 DEBUG throttling before swapping tables
2017-04-24 18:13:20 DEBUG throttling before swapping tables
2017-04-24 18:13:21 DEBUG throttling before swapping tables
2017-04-24 18:13:21 DEBUG throttling before swapping tables
2017/04/24 18:13:21 binlogsyncer.go:568: [info] rotate to (binlog.037232, 4)
2017/04/24 18:13:21 binlogsyncer.go:568: [info] rotate to (binlog.037232, 4)
2017-04-24 18:13:21 INFO rotate to next log name: binlog.037232
2017-04-24 18:13:21 INFO rotate to next log name: binlog.037232
2017-04-24 18:13:21 DEBUG throttling before swapping tables
2017-04-24 18:13:21 DEBUG throttling before swapping tables
2017-04-24 18:13:22 DEBUG throttling before swapping tables
2017-04-24 18:13:22 DEBUG throttling before swapping tables
2017-04-24 18:13:22 DEBUG throttling before swapping tables
2017-04-24 18:13:22 DEBUG throttling before swapping tables
2017-04-24 18:13:23 DEBUG throttling before swapping tables
2017-04-24 18:13:23 DEBUG throttling before swapping tables
2017-04-24 18:13:23 DEBUG throttling before swapping tables
2017-04-24 18:13:23 DEBUG throttling before swapping tables
2017-04-24 18:13:24 DEBUG throttling before swapping tables
2017-04-24 18:13:24 DEBUG throttling before swapping tables
2017-04-24 18:13:24 DEBUG throttling before swapping tables
2017/04/24 18:13:24 binlogsyncer.go:568: [info] rotate to (binlog.037233, 4)
2017/04/24 18:13:24 binlogsyncer.go:568: [info] rotate to (binlog.037233, 4)
2017-04-24 18:13:24 INFO rotate to next log name: binlog.037233
2017-04-24 18:13:24 INFO rotate to next log name: binlog.037233
2017-04-24 18:13:24 DEBUG throttling before swapping tables
2017-04-24 18:13:25 DEBUG throttling before swapping tables
2017-04-24 18:13:25 DEBUG throttling before swapping tables
2017-04-24 18:13:25 DEBUG throttling before swapping tables
2017-04-24 18:13:25 DEBUG throttling before swapping tables
2017-04-24 18:13:26 DEBUG throttling before swapping tables
2017-04-24 18:13:26 DEBUG throttling before swapping tables
2017-04-24 18:13:26 DEBUG throttling before swapping tables
2017-04-24 18:13:26 DEBUG throttling before swapping tables
2017-04-24 18:13:27 DEBUG throttling before swapping tables
2017-04-24 18:13:27 DEBUG throttling before swapping tables
2017-04-24 18:13:27 DEBUG throttling before swapping tables
2017-04-24 18:13:27 DEBUG throttling before swapping tables
2017-04-24 18:13:28 DEBUG throttling before swapping tables
2017-04-24 18:13:28 DEBUG throttling before swapping tables
2017-04-24 18:13:28 DEBUG throttling before swapping tables
2017-04-24 18:13:28 DEBUG throttling before swapping tables
Copy: 19058539/19058539 100.0%; Applied: 90780; Backlog: 1/100; Time: 2h43m30s(total), 2h34m29s(copy); streamer: binlog.037260:42613044; State: migrating; ETA: due
2017-04-24 18:13:29 DEBUG throttling before swapping tables
2017-04-24 18:13:29 DEBUG throttling before swapping tables
2017-04-24 18:13:29 DEBUG throttling before swapping tables
2017-04-24 18:13:29 DEBUG throttling before swapping tables
2017-04-24 18:13:30 DEBUG throttling before swapping tables
2017-04-24 18:13:30 DEBUG throttling before swapping tables
2017-04-24 18:13:30 DEBUG throttling before swapping tables
2017-04-24 18:13:30 DEBUG throttling before swapping tables
2017-04-24 18:13:31 DEBUG throttling before swapping tables
2017-04-24 18:13:31 DEBUG throttling before swapping tables
2017-04-24 18:13:31 DEBUG throttling before swapping tables
2017-04-24 18:13:31 DEBUG throttling before swapping tables
2017-04-24 18:13:32 DEBUG throttling before swapping tables
2017-04-24 18:13:32 DEBUG throttling before swapping tables
2017-04-24 18:13:32 DEBUG throttling before swapping tables
2017-04-24 18:13:32 DEBUG throttling before swapping tables
2017-04-24 18:13:33 DEBUG throttling before swapping tables
2017-04-24 18:13:33 DEBUG throttling before swapping tables
2017-04-24 18:13:33 DEBUG throttling before swapping tables
2017-04-24 18:13:33 DEBUG throttling before swapping tables
2017/04/24 18:13:33 binlogsyncer.go:568: [info] rotate to (binlog.037234, 4)
2017/04/24 18:13:33 binlogsyncer.go:568: [info] rotate to (binlog.037234, 4)
2017-04-24 18:13:33 INFO rotate to next log name: binlog.037234
2017-04-24 18:13:33 INFO rotate to next log name: binlog.037234
2017-04-24 18:13:34 DEBUG throttling before swapping tables
2017-04-24 18:13:34 DEBUG throttling before swapping tables
2017-04-24 18:13:34 DEBUG throttling before swapping tables
2017-04-24 18:13:34 DEBUG throttling before swapping tables
2017-04-24 18:13:35 DEBUG throttling before swapping tables
2017-04-24 18:13:35 DEBUG throttling before swapping tables
2017-04-24 18:13:35 DEBUG throttling before swapping tables
2017-04-24 18:13:35 DEBUG throttling before swapping tables
2017-04-24 18:13:36 DEBUG throttling before swapping tables
2017-04-24 18:13:36 DEBUG throttling before swapping tables
2017-04-24 18:13:36 DEBUG throttling before swapping tables
2017-04-24 18:13:36 DEBUG throttling before swapping tables
2017-04-24 18:13:37 DEBUG throttling before swapping tables
2017-04-24 18:13:37 DEBUG throttling before swapping tables
2017-04-24 18:13:37 DEBUG throttling before swapping tables
2017-04-24 18:13:37 DEBUG throttling before swapping tables
2017-04-24 18:13:38 DEBUG throttling before swapping tables
2017-04-24 18:13:38 DEBUG throttling before swapping tables
2017-04-24 18:13:38 DEBUG throttling before swapping tables
2017-04-24 18:13:38 DEBUG throttling before swapping tables
2017-04-24 18:13:39 DEBUG throttling before swapping tables
2017-04-24 18:13:39 DEBUG throttling before swapping tables
2017-04-24 18:13:39 DEBUG throttling before swapping tables
2017-04-24 18:13:39 DEBUG throttling before swapping tables
2017/04/24 18:13:40 binlogsyncer.go:568: [info] rotate to (binlog.037235, 4)
2017/04/24 18:13:40 binlogsyncer.go:568: [info] rotate to (binlog.037235, 4)
Copy: 19058539/19058539 100.0%; Applied: 90780; Backlog: 5/100; Time: 2h43m35s(total), 2h34m29s(copy); streamer: binlog.037260:58013120; State: throttled, lag=3.000000s; ETA: due
2017-04-24 18:13:40 INFO rotate to next log name: binlog.037235
2017-04-24 18:13:40 INFO rotate to next log name: binlog.037235
2017-04-24 18:13:40 DEBUG throttling before swapping tables
2017-04-24 18:13:40 DEBUG throttling before swapping tables
2017-04-24 18:13:40 DEBUG throttling before swapping tables
2017-04-24 18:13:40 DEBUG throttling before swapping tables
2017-04-24 18:13:41 DEBUG throttling before swapping tables
2017-04-24 18:13:41 DEBUG throttling before swapping tables
2017-04-24 18:13:41 DEBUG throttling before swapping tables
2017-04-24 18:13:41 DEBUG throttling before swapping tables
2017-04-24 18:13:42 DEBUG throttling before swapping tables
2017-04-24 18:13:42 DEBUG throttling before swapping tables
# Migrating `app`.`TableName`; Ghost table is `app`.`_TableName_gho`
# Migrating hostname.somewhere.com:3306; inspecting HOSTNAME:3306; executing on HOSTNAME
# Migration started at Mon Apr 24 15:38:03 +0200 2017
# chunk-size: 1000; max-lag-millis: 1500ms; max-load: ; critical-load: ; nice-ratio: 0.000000
# throttle-additional-flag-file: /tmp/gh-ost.throttle
# throttle-control-replicas count: 1
# Serving on unix socket: /tmp/gh-ost.app.TableName.sock
Copy: 19058539/19058539 100.0%; Applied: 90780; Backlog: 0/100; Time: 2h43m36s(total), 2h34m29s(copy); streamer: binlog.037260:58855906; State: migrating; ETA: due
2017-04-24 18:13:42 DEBUG throttling before swapping tables
2017-04-24 18:13:42 DEBUG throttling before swapping tables
2017-04-24 18:13:43 DEBUG throttling before swapping tables
2017-04-24 18:13:43 DEBUG throttling before swapping tables
# Done
2017-04-24 18:13:43 DEBUG throttling before swapping tables

2017-04-24 18:13:43 DEBUG throttling before swapping tables
2017-04-24 18:13:44 DEBUG throttling before swapping tables
2017-04-24 18:13:44 DEBUG throttling before swapping tables
2017-04-24 18:13:44 DEBUG throttling before swapping tables
2017-04-24 18:13:44 DEBUG throttling before swapping tables
2017-04-24 18:13:45 DEBUG throttling before swapping tables
2017-04-24 18:13:45 DEBUG throttling before swapping tables
2017-04-24 18:13:45 DEBUG throttling before swapping tables
2017-04-24 18:13:45 DEBUG throttling before swapping tables
2017-04-24 18:13:46 DEBUG throttling before swapping tables
```

and now it exits successfully, the new and old tables have identical content and replication is NOT running. I didn't

So in the log there is a fair amount of confusion: gh-ost stops replication but then complains about it not running, complains about tables already existing, says cut-over failed, says it starts replication, stops it without saying so.