ceremonyclient/pebble/testdata/compaction_iter_delete_sized

define
a.SET.1:b
----

iter
first
next
----
a#1,1:b
.

define
a.SET.2:c
a.SET.1:b
----

iter
first
next
----
a#2,1:c
.

iter snapshots=0
first
next
----
a#2,1:c
.

iter snapshots=1
first
next
----
a#2,1:c
.

iter snapshots=2
first
next
next
----
a#2,1:c
a#1,1:b
.

define
a.DEL.2:
a.SET.1:b
----

iter
first
next
----
a#2,0:
.

iter elide-tombstones=true
first
----
.

iter elide-tombstones=true snapshots=2
first
next
next
----
a#2,0:
a#1,1:b
.

iter elide-tombstones=true snapshots=1
first
next
----
a#2,0:
.

define
a.DEL.2:
a.SET.1:b
b.SET.3:c
----

iter
first
next
next
----
a#2,0:
b#3,1:c
.

iter snapshots=1
first
next
next
----
a#2,0:
b#3,1:c
.

iter snapshots=2
first
next
next
next
----
a#2,0:
a#1,1:b
b#3,1:c
.

define
a.SET.1:a
b.SET.2:b
c.SET.3:c
----

iter
first
next
next
next
----
a#1,1:a
b#2,1:b
c#3,1:c
.

define
a.MERGE.3:d
a.MERGE.2:c
a.SET.1:b
b.MERGE.2:b
b.MERGE.1:a
----

iter
first
next
next
----
a#3,1:bcd[base]
b#2,2:ab
.

iter snapshots=3 print-snapshot-pinned print-force-obsolete
first
next
next
next
----
a#3,2:d (not pinned) (not force obsolete)
a#2,1:bc[base] (pinned) (not force obsolete)
b#2,2:ab (not pinned) (not force obsolete)
.

define
a.SET.9:b
a.DEL.8:
a.SET.7:d
a.DEL.6:
a.SET.5:f
----

iter
first
next
----
a#9,18:b
.

iter snapshots=6
first
next
next
----
a#9,18:b
a#5,1:f
.

iter snapshots=7
first
next
next
----
a#9,18:b
a#6,0:
.

iter snapshots=8
first
next
next
----
a#9,18:b
a#7,18:d
.

iter snapshots=9
first
next
next
----
a#9,1:b
a#8,0:
.

iter snapshots=10
first
next
----
a#9,18:b
.

iter snapshots=(5,6,7,8,9)
first
next
next
next
next
next
----
a#9,1:b
a#8,0:
a#7,1:d
a#6,0:
a#5,1:f
.

define
a.INVALID.2:b
a.SET.1:c
----

iter
first
----
err=invalid internal key kind: INVALID

define
a.SET.2:b
a.INVALID.1:c
----

iter
first
next
----
a#2,18:b
err=invalid internal key kind: INVALID

define
a.MERGE.2:b
a.INVALID.1:c
----

iter
first
next
----
a#2,2:b
err=invalid internal key kind: INVALID

define
a.INVALID.2:c
a.RANGEDEL.1:d
----

iter
first
tombstones
----
err=invalid internal key kind: INVALID
.

define
a.MERGE.2:b
a.MERGE.1:c
a.MERGE.0:d
----

iter snapshots=(1,2) print-snapshot-pinned print-force-obsolete
first
next
next
next
----
a#2,2:b (not pinned) (not force obsolete)
a#1,2:c (pinned) (not force obsolete)
a#0,2:d (pinned) (not force obsolete)
.

define
a.SET.2:b
a.RANGEDEL.1:c
b.RANGEDEL.4:d
b.SET.2:e
c.SET.3:f
----

iter
first
next
next
next
tombstones
----
a#2,18:b
a#1,15:c
b#4,15:d
.
a-b#1
b-c#4
c-d#4
.

iter snapshots=2
first
next
next
next
tombstones
----
a#2,1:b
a#1,15:c
b#4,15:d
.
a-b#1
b-c#4
b-c#1
c-d#4
.

iter snapshots=3 print-snapshot-pinned print-force-obsolete
first
next
next
next
next
tombstones
----
a#2,18:b (not pinned) (not force obsolete)
a#1,15:c (not pinned) (not force obsolete)
b#4,15:d (not pinned) (not force obsolete)
b#2,1:e (pinned) (force obsolete)
.
a-b#1
b-c#4
b-c#1
c-d#4
.

iter snapshots=4 print-snapshot-pinned print-force-obsolete
first
next
next
next
next
next
tombstones
----
a#2,18:b (not pinned) (not force obsolete)
a#1,15:c (not pinned) (not force obsolete)
b#4,15:d (not pinned) (not force obsolete)
b#2,1:e (pinned) (force obsolete)
c#3,1:f (pinned) (force obsolete)
.
a-b#1
b-c#4
b-c#1
c-d#4
.

define
a.RANGEDEL.3:e
b.SET.4:b
c.SET.3:c
d.SET.2:d
e.SET.1:e
----

iter
first
next
next
next
next
tombstones
----
a#3,15:e
b#4,1:b
c#3,1:c
e#1,1:e
.
a-e#3
.

define
a.RANGEDEL.3:e
b.MERGE.4:b
c.MERGE.3:c
d.MERGE.2:d
e.MERGE.1:e
----

iter
first
next
next
next
next
tombstones
----
a#3,15:e
b#4,2:b
c#3,2:c
e#1,2:e
.
a-e#3
.

define
a.RANGEDEL.3:c
b.MERGE.5:e
b.MERGE.4:d
b.MERGE.2:c
b.MERGE.1:b
d.MERGE.5:c
d.MERGE.4:b
d.RANGEDEL.3:f
d.MERGE.2:e
d.MERGE.1:d
----

iter
first
next
next
next
next
tombstones
----
a#3,15:c
b#5,1:de[base]
d#5,2:bc
d#3,15:f
.
a-c#3
d-f#3
.

define
a.RANGEDEL.3:d
b.RANGEDEL.2:e
c.RANGEDEL.1:f
----

iter
first
next
next
next
tombstones
----
a#3,15:d
b#2,15:e
c#1,15:f
.
a-b#3
b-c#3
c-d#3
d-e#2
e-f#1
.

iter snapshots=2
first
next
next
next
tombstones
----
a#3,15:d
b#2,15:e
c#1,15:f
.
a-b#3
b-c#3
c-d#3
c-d#1
d-e#2
d-e#1
e-f#1
.

iter snapshots=3
first
next
next
next
tombstones
----
a#3,15:d
b#2,15:e
c#1,15:f
.
a-b#3
b-c#3
b-c#2
c-d#3
c-d#2
d-e#2
e-f#1
.

iter snapshots=(2,3)
first
next
next
next
tombstones
----
a#3,15:d
b#2,15:e
c#1,15:f
.
a-b#3
b-c#3
b-c#2
c-d#3
c-d#2
c-d#1
d-e#2
d-e#1
e-f#1
.

define
a.RANGEDEL.10:k
f.SET.9:f
f.SET.8:f
----

iter snapshots=(9,10) print-snapshot-pinned print-force-obsolete
first
next
tombstones f
next
tombstones
----
a#10,15:k (not pinned) (not force obsolete)
f#9,1:f (pinned) (force obsolete)
a-f#10
.
f#8,1:f (pinned) (force obsolete)
f-k#10
.

define
f.RANGEDEL.10:k
f.SET.9:f
f.SET.8:f
----

iter snapshots=(9,10)
first
next
tombstones f
next
tombstones
----
f#10,15:k
f#9,1:f
.
f#8,1:f
f-k#10
.

define
a.SET.1:a
b.RANGEDEL.2:d
c.RANGEDEL.3:e
d.SET.4:d
----

iter
first
next
next
next
tombstones c
tombstones
----
a#1,1:a
b#2,15:d
c#3,15:e
d#4,1:d
b-c#2
.
c-d#3
d-e#3
.

iter snapshots=3
first
next
next
next
tombstones c
tombstones
----
a#1,1:a
b#2,15:d
c#3,15:e
d#4,1:d
b-c#2
.
c-d#3
c-d#2
d-e#3
.

define
a.SET.1:a
b.RANGEDEL.2:d
c.SET.4:d
----

iter
first
next
next
tombstones c
tombstones
----
a#1,1:a
b#2,15:d
c#4,1:d
b-c#2
.
c-d#2
.

define
a.RANGEDEL.2:d
a.SET.2:a
b.SET.2:b
c.SET.2:c
----

iter
first
next
next
next
next
----
a#2,15:d
a#2,1:a
b#2,1:b
c#2,1:c
.

define
a.SINGLEDEL.1:
----

iter
first
next
----
a#1,7:
.

iter elide-tombstones=true
first
----
.

define
a.SINGLEDEL.2:
a.SINGLEDEL.1:
----

iter
first
next
----
a#2,7:
.

define
a.SINGLEDEL.3:
a.SINGLEDEL.2:
a.SET.1:a
----

iter
first
----
.

define
a.SET.3:a
b.SINGLEDEL.2:
b.DEL.1:
----

iter
first
next
next
----
a#3,1:a
b#2,0:
.

define
a.SINGLEDEL.2:
a.DEL.1:
----

iter
first
next
----
a#2,0:
.

iter elide-tombstones=true
first
----
.

define
a.SINGLEDEL.2:
a.MERGE.1:
----

iter
first
next
----
a#2,0:
.

iter elide-tombstones=true
first
----
.

define
a.SINGLEDEL.2:
a.SET.1:b
----

iter
first
----
.

# SET that meets a SINGLEDEL is transformed into a SETWITHDEL.

define
a.SET.2:b
a.SINGLEDEL.1:
----

iter
first
next
----
a#2,18:b
.

define
a.MERGE.6:b
a.SINGLEDEL.5:
a.SET.4:a
----

iter
first
next
----
a#6,18:b[base]
.

# Non-deterministic use of SINGLEDEL where there are two older SETs that have
# not been deleted or single deleted. It is permitted to shadow both.
define
a.MERGE.6:b
a.SINGLEDEL.5:
a.SET.4:a
a.SET.3:a
----

iter
first
next
----
a#6,18:b[base]
.

define
a.SINGLEDEL.2:
a.SET.1:b
b.SET.3:c
----

iter
first
next
----
b#3,1:c
.

define
a.SINGLEDEL.3:
a.SET.2:b
a.SET.1:a
----

iter
first
next
----
a#1,1:a
.

define
a.SINGLEDEL.3:
a.MERGE.2:b
a.MERGE.1:a
----

iter
first
next
----
a#3,0:
.

define
a.SINGLEDEL.4:
a.SET.3:val
a.SINGLEDEL.2:
a.SET.1:val
----

iter
first
----
.

iter snapshots=2
first
next
next
----
a#2,7:
a#1,1:val
.

define
a.SINGLEDEL.4:
a.SET.3:val
a.DEL.2:
a.SET.1:val
----

iter
first
next
----
a#2,0:
.

iter snapshots=2
first
next
next
----
a#2,0:
a#1,1:val
.

iter snapshots=3
first
next
----
a#2,0:
.

iter snapshots=(2,3)
first
next
next
----
a#2,0:
a#1,1:val
.

define
a.SINGLEDEL.4:
a.SET.3:c
a.MERGE.2:b
a.SET.1:a
----

iter
first
next
----
a#2,1:ab[base]
.

iter snapshots=2
first
next
next
----
a#2,2:b
a#1,1:a
.

iter snapshots=3
first
next
----
a#2,1:ab[base]
.

iter snapshots=(2,3,4)
first
next
next
next
next
----
a#4,7:
a#3,1:c
a#2,2:b
a#1,1:a
.

define
a.SINGLEDEL.3:
a.RANGEDEL.2:c
a.SET.1:val
----

iter
first
next
next
tombstones
----
a#3,7:
a#2,15:c
.
a-c#2
.

define
a.RANGEDEL.3:d
a.DEL.2:
a.SET.1:a
d.DEL.2:
----

iter
first
next
next
tombstones
----
a#3,15:d
d#2,0:
.
a-d#3
.

iter snapshots=3
first
next
next
next
----
a#3,15:d
a#2,0:
d#2,0:
.

iter snapshots=2
first
next
next
next
----
a#3,15:d
a#1,1:a
d#2,0:
.

iter snapshots=1
first
next
next
----
a#3,15:d
d#2,0:
.

define
a.MERGE.2:a
b.RANGEDEL.1:c
----

iter
first
tombstones a
next
next
tombstones
----
a#2,2:a
.
b#1,15:c
.
b-c#1
.

define
a.MERGE.2:v2
a.RANGEDEL.1:b
a.MERGE.1:v1
----

iter allow-zero-seqnum=true
first
next
next
next
tombstones
----
a#2,2:v2
a#1,15:b
a#0,2:v1
.
a-b#1
.

# Verify that we transform merge+del -> set.

define
a.MERGE.5:5
a.DEL.3:
a.MERGE.1:1
----

iter
first
next
----
a#5,18:5[base]
.

iter allow-zero-seqnum=true
first
next
----
a#0,18:5[base]
.

iter elide-tombstones=true
first
next
----
a#5,18:5[base]
.

iter snapshots=2
first
next
next
----
a#5,18:5[base]
a#1,2:1
.

iter snapshots=2 elide-tombstones=true
first
next
next
----
a#5,18:5[base]
a#1,2:1
.

# Verify that we transform merge+rangedel -> set. This isn't strictly
# necessary, but provides consistency with the behavior for merge+del.

define
a.RANGEDEL.3:c
b.MERGE.5:5
b.SET.2:2
b.MERGE.1:1
----

iter
first
next
next
----
a#3,15:c
b#5,1:5[base]
.

iter allow-zero-seqnum=true
first
next
next
----
a#3,15:c
b#0,1:5[base]
.

iter snapshots=2
first
next
next
----
a#3,15:c
b#5,1:5[base]
b#1,2:1

define
a.RANGEDEL.3:c
b.MERGE.5:5
b.MERGE.2:2
b.MERGE.1:1
----

iter
first
next
next
----
a#3,15:c
b#5,1:5[base]
.

iter snapshots=2
first
next
next
----
a#3,15:c
b#5,1:5[base]
b#1,2:1

# SET that meets a DEL is transformed into a SETWITHDEL.

define
a.SET.2:b
a.DEL.1:
----

iter
first
next
----
a#2,18:b
.

iter snapshots=2
first
next
next
----
a#2,1:b
a#1,0:
.

define
a.SET.3:c
a.DEL.2:
a.SET.1:b
----

iter
first
next
----
a#3,18:c
.

iter snapshots=2
first
next
next
----
a#3,18:c
a#1,1:b
.

define
a.SET.3:c
a.SET.2:b
a.DEL.1:
----

iter
first
next
----
a#3,18:c
.

iter snapshots=3
first
next
next
----
a#3,1:c
a#2,18:b
.

iter snapshots=2
first
next
next
----
a#3,1:c
a#1,0:
.

define
a.DEL.3:
a.SET.2:b
a.DEL.1:
----

iter
first
next
----
a#3,0:
.

iter snapshots=3
first
next
next
----
a#3,0:
a#2,18:b
.

iter snapshots=2
first
next
next
----
a#3,0:
a#1,0:
.

# SETWITHDEL-eligible entries at or under a RANGEDEL at the same user key should
# be skipped.
define
a.SET.3:c
a.RANGEDEL.2:z
a.SET.2:b
a.DEL.1:
----

iter allow-zero-seqnum=true
first
next
next
----
a#0,18:c
a#2,15:z
.

iter allow-zero-seqnum=true snapshots=3
first
next
next
next
----
a#3,1:c
a#2,15:z
a#0,18:b
.

iter allow-zero-seqnum=true snapshots=2
first
next
next
next
----
a#3,18:c
a#2,15:z
a#1,0:
.

define
a.SET.4:c
a.RANGEDEL.3:z
a.SET.2:b
a.DEL.1:
----

iter
first
next
next
----
a#4,18:c
a#3,15:z
.

# Invalid keys are emitted under SETWITHDEL.

define
a.SET.2:b
a.INVALID.1:
----

iter
first
next
----
a#2,18:b
err=invalid internal key kind: INVALID

define
a.SET.3:c
a.INVALID.2:
a.SET.1:b
----

iter
first
next
----
a#3,18:c
err=invalid internal key kind: INVALID

# SINGLEDEL that meets a SETWITHDEL is transformed into a DEL.

define
a.SINGLEDEL.3:
a.SETWITHDEL.2:d
b.SET.1:c
----

iter
first
next
next
----
a#3,0:
b#1,1:c
.

iter snapshots=2
first
next
next
----
a#3,0:
b#1,1:c
.

iter snapshots=3
first
next
next
next
----
a#3,7:
a#2,18:d
b#1,1:c
.

define
a.SETWITHDEL.3:3
a.SET.2:d
b.SET.1:c
----

iter print-missized-dels
first
next
next
----
a#3,18:3
b#1,1:c
.
missized-dels=0

iter snapshots=3
first
next
next
next
----
a#3,18:3
a#2,1:d
b#1,1:c
.

# Test a DELSIZED whose encoded value matches the size of a deleted key. The
# DELSIZED's value should be removed, reflecting that the tombstone already
# dropped the key that it was expected to drop.

define
a.SET.9:foo
b.DELSIZED.8:varint(11)
b.SET.5:helloworld
c.SET.2:bar
----

iter print-missized-dels
first
next
next
----
a#9,1:foo
b#8,23:
c#2,1:bar
missized-dels=0

# Test two DELSIZEDs meeting. The lower-sequenced number value should carry
# forward, at the higher sequence number. The first DELSIZED should be consider
# missized: It never found the key it was supposed to delete.

define
a.SET.9:foo
b.DELSIZED.9:varint(20)
b.DELSIZED.8:varint(10)
c.SET.2:bar
----

iter print-missized-dels
first
next
next
----
a#9,1:foo
b#9,23:varint(10)
c#2,1:bar
missized-dels=1

# Test a DELSIZED whose encoded value is larger than the size of the deleted
# key. The DELSIZED should be replaced by an ordinary DEL with the same sequence
# number.

define
a.SET.2:foo
b.DELSIZED.8:varint(25)
b.SET.3:hello
c.SET.9:bar
----

iter print-missized-dels
first
next
next
----
a#2,1:foo
b#8,0:
c#9,1:bar
missized-dels=1

# Test two DELSIZED at the same user key, but with correctly sized deleted keys.

define
a.DELSIZED.9:varint(4)
a.SET.8:foo
a.DELSIZED.8:varint(6)
a.SET.5:hello
----

iter print-missized-dels
first
next
----
a#9,23:
.
missized-dels=0

# Test the above scenario, except the second DELSIZED is missized. It should
# still count as missized.

define
a.DELSIZED.9:varint(4)
a.SET.8:foo
a.DELSIZED.8:varint(1)
a.SET.5:hello
----

iter print-missized-dels
first
next
----
a#9,0:
.
missized-dels=1

# Test the above scenario, except the second tombstone is a DEL. It should
# NOT count as missized.

define
a.DELSIZED.9:varint(4)
a.SET.8:foo
a.DEL.8:
a.SET.5:hello
----

iter print-missized-dels
first
next
----
a#9,0:
.
missized-dels=0

# Test various DELSIZEDs beneath live keys. SETS should be converted to
# SETWITHDELs when they meet a DELSIZED.

define
a.SET.7:foo
a.DELSIZED.5:varint(5)
b.SET.4:bar
b.DELSIZED.2:varint(4)
b.SET.1:bax
c.SET.9:coconut
c.DEL.8:del
c.DELSIZED.5:varint(2)
d.SET.8:dragonfruit
----

iter print-missized-dels
first
next
next
next
next
----
a#7,18:foo
b#4,18:bar
c#9,18:coconut
d#8,1:dragonfruit
.
missized-dels=0

# Test a DELSIZED meeting a MERGE. This counts as a missized DEL—The user can't
# know the value of the most recent MERGE since it's dependent on LSM state.

define
a.DELSIZED.9:varint(4)
a.MERGE.8:fo
a.MERGE.7:o
----

iter print-missized-dels
first
next
----
a#9,0:
.
missized-dels=1

# Test a DELSIZED that shadows a SINGLEDEL'd key.

define
a.DELSIZED.4:varint(4)
b.SINGLEDEL.3:
b.SET.1:val
----

iter
first
next
tombstones
----
a#4,23:varint(4)
.
.

# Repeat the above but with elision of tombstones.

iter elide-tombstones=t
first
tombstones
----
.
.

# Test DELSIZED shadowing SINGLEDEL.

define
a.DELSIZED.4:varint(4)
a.SET.2:foo
b.SINGLEDEL.3:
b.SET.1:val
----

iter
first
next
tombstones
----
a#4,23:
.
.

# Repeat the above but with elision of tombstones.

iter elide-tombstones=t
first
tombstones
----
.
.

# Test a very subtle sequence where a elision of tombstones is active, and a
# unskippable RANGEDEL sits between a DELSIZED and the key it was intended to
# delete. The unskippable RANGEDEL breaks the skipping of keys within the
# snapshot stripe, but it's ultimately okay because we preserve skip=true across
# the RANGEDEL return.

define
a.DELSIZED.5:varint(4)
a.RANGEDEL.4:d
a.SET.3:foo
----

iter elide-tombstones=t
first
next
tombstones
----
a#4,15:d
.
.

# Try the same test as above, but with allowing sequence number zeroing as well.

iter elide-tombstones=t allow-zero-seqnum=t
first
next
tombstones
----
a#4,15:d
.
.

# Perform a variant of the above test but with a DEL key.

define
a.DEL.5:
a.RANGEDEL.4:d
a.SET.3:foo
----

iter elide-tombstones=t
first
next
tombstones
----
a#4,15:d
.
.

# Perform a variant of the above test but with a SINGLEDEL key.

define
a.SINGLEDEL.5:
a.RANGEDEL.4:d
a.SET.3:foo
----

iter elide-tombstones=t
first
next
tombstones
----
a#4,15:d
.
.

# Perform a few variants of the above but with a range del with a seqnum equal to
# keys. NB: When seqnums are equal, the order of keys with various kinds is:
#
# DeleteSized < RangeKey{Delete,Unset,Set} < SetWithDelete < RangeDelete < SingleDelete < Set < Delete
#
# NB: Range keys are interleaved always at the maximal sequence number, so the
# compaction iterator should always observe them first.

define
a.SINGLEDEL.6:
a.SETWITHDEL.5:foo
a.RANGEDEL.5:z
----

define-range-keys
a-z:{(#5,RANGEKEYDEL)}
----

# In the following case, the SINGLEDEL meets a SETWITHDEL, promoting the
# SINGLEDEL into a DEL.

iter
first
next
next
next
tombstones
----
a#72057594037927935,19:
a#6,0:
a#5,15:z
.
a-z#5
.

# In this case, SINGLEDEL is elided (despite its transformation into a DEL) due
# to elide-tombstones=t.

iter elide-tombstones=t
first
next
next
tombstones
----
a#72057594037927935,19:
a#5,15:z
.
.

define
a.SINGLEDEL.6:
a.RANGEDEL.5:d
a.SET.5:foo
----

# NB: In this case, the RANGEDEL acts as an unintentional snapshot stripe
# change. This is a code artifact, and we will be able to remove this behavior
# when range deletes are interleaved at the maximal sequence number by an
# interleaving iterator (like range keys are).

iter
first
next
next
next
tombstones
----
a#6,7:
a#5,15:d
a#5,1:foo
.
a-d#5
.

iter elide-tombstones=t allow-zero-seqnum=t
first
next
tombstones
----
a#5,15:d
.
.

define
a.SINGLEDEL.6:
a.SETWITHDEL.5:foo
a.RANGEDEL.5:d
----

# When the SINGLEDEL and SETWITHDEL meet, the SINGLEDEL is promoted into a DEL.

iter
first
next
tombstones
----
a#6,0:
a#5,15:d
a-d#5
.

iter elide-tombstones=t
first
next
tombstones
----
a#5,15:d
.
.

define
a.DELSIZED.6:varint(3)
a.RANGEDEL.5:d
a.SET.5:foo
----

iter
first
next
tombstones
----
a#6,23:varint(3)
a#5,15:d
a-d#5
.

iter elide-tombstones=t
first
next
tombstones
----
a#5,15:d
.
.

# Test a DELSIZED with a value that fails to decode.

define
a.DELSIZED.5:notavarint
a.SET.4:foo
----

iter
first
----
err=DELSIZED holds invalid value: 6e6f7461766172696e74

# Test a value-less DELSIZED.

define
a.DELSIZED.5:
a.SET.4:foo
a.SET.3:bar
----

iter print-missized-dels
first
next
----
a#5,0:
.
missized-dels=0

# Regression test for #3087.
#
# When a DELSIZED and a SINGLEDEL meet in a compaction, a DEL key should be
# emitted.

define
a.DELSIZED.5:
a.SINGLEDEL.3:
a.SET.2:foo
a.SET.1:bar
----

iter
first
next
----
a#5,0:
.

# When a MERGE and a DEL[SIZED] meet in a compaction, a SETWITHDEL key (NOT a
# SET) should be emitted. Otherwise, a sequence such as SINGLEDDEL, MERGE, DEL,
# SET could result in the SET re-appearing.

define
a.MERGE.5:foo
a.DEL.3:
----

iter
first
next
----
a#5,18:foo[base]
.