[PATCH 08/13] gc: keep track of available checkpoints

[Vladimir Davydov <vdavydov.dev@gmail.com>]

Currently, the checkpoint iterator is in fact a wrapper around
memtx_engine::snap_dir while the garbage collector knows nothing about
checkpoints. This feels like encapsulation violation. Let's keep track
of all available checkpoints right in the garbage collector instead
and export gc_ API to iterate over checkpoints.
---
 src/box/CMakeLists.txt |  1 -
 src/box/box.cc         | 50 ++++++++++++++------------
 src/box/checkpoint.c   | 72 -------------------------------------
 src/box/checkpoint.h   | 97 --------------------------------------------------
 src/box/gc.c           | 84 ++++++++++++++++++++++++++++++++++---------
 src/box/gc.h           | 68 ++++++++++++++++++++++++++++++-----
 src/box/lua/info.c     | 10 ++----
 src/box/memtx_engine.c |  7 ++++
 src/box/vinyl.c        |  3 +-
 src/box/vy_scheduler.c |  1 -
 10 files changed, 167 insertions(+), 226 deletions(-)
 delete mode 100644 src/box/checkpoint.c
 delete mode 100644 src/box/checkpoint.h

diff --git a/src/box/CMakeLists.txt b/src/box/CMakeLists.txt
index 67750898..52413d3c 100644
--- a/src/box/CMakeLists.txt
+++ b/src/box/CMakeLists.txt
@@ -102,7 +102,6 @@ add_library(box STATIC
     txn.c
     box.cc
     gc.c
-    checkpoint.c
     user_def.c
     user.cc
     authentication.cc
diff --git a/src/box/box.cc b/src/box/box.cc
index 49deea61..a33b80ef 100644
--- a/src/box/box.cc
+++ b/src/box/box.cc
@@ -68,7 +68,6 @@
 #include "authentication.h"
 #include "path_lock.h"
 #include "gc.h"
-#include "checkpoint.h"
 #include "systemd.h"
 #include "call.h"
 #include "func.h"
@@ -1446,17 +1445,20 @@ box_process_join(struct ev_io *io, struct xrow_header *header)
 			  "wal_mode = 'none'");
 	}
 
-	/* Remember start vclock. */
-	struct vclock start_vclock;
 	/*
 	 * The only case when the directory index is empty is
 	 * when someone has deleted a snapshot and tries to join
 	 * as a replica. Our best effort is to not crash in such
 	 * case: raise ER_MISSING_SNAPSHOT.
 	 */
-	if (checkpoint_last(&start_vclock) < 0)
+	struct gc_checkpoint *checkpoint = gc_last_checkpoint();
+	if (checkpoint == NULL)
 		tnt_raise(ClientError, ER_MISSING_SNAPSHOT);
 
+	/* Remember start vclock. */
+	struct vclock start_vclock;
+	vclock_copy(&start_vclock, &checkpoint->vclock);
+
 	/* Register the replica with the garbage collector. */
 	struct gc_consumer *gc = gc_consumer_register(&start_vclock,
 		GC_CONSUMER_WAL, "replica %s", tt_uuid_str(&instance_uuid));
@@ -1725,6 +1727,8 @@ bootstrap_master(const struct tt_uuid *replicaset_uuid)
 	if (engine_begin_checkpoint() ||
 	    engine_commit_checkpoint(&replicaset.vclock))
 		panic("failed to create a checkpoint");
+
+	gc_add_checkpoint(&replicaset.vclock);
 }
 
 /**
@@ -1785,6 +1789,8 @@ bootstrap_from_master(struct replica *master)
 	if (engine_begin_checkpoint() ||
 	    engine_commit_checkpoint(&replicaset.vclock))
 		panic("failed to create a checkpoint");
+
+	gc_add_checkpoint(&replicaset.vclock);
 }
 
 /**
@@ -2036,8 +2042,7 @@ box_cfg_xc(void)
 	xstream_create(&join_stream, apply_initial_join_row);
 	xstream_create(&subscribe_stream, apply_row);
 
-	struct vclock last_checkpoint_vclock;
-	int64_t last_checkpoint_lsn = checkpoint_last(&last_checkpoint_vclock);
+	struct gc_checkpoint *checkpoint = gc_last_checkpoint();
 
 	/*
 	 * Lock the write ahead log directory to avoid multiple
@@ -2051,14 +2056,14 @@ box_cfg_xc(void)
 		 * refuse to start. In hot standby mode, a busy
 		 * WAL dir must contain at least one xlog.
 		 */
-		if (!cfg_geti("hot_standby") || last_checkpoint_lsn < 0)
+		if (!cfg_geti("hot_standby") || checkpoint == NULL)
 			tnt_raise(ClientError, ER_ALREADY_RUNNING, cfg_gets("wal_dir"));
 	}
 	bool is_bootstrap_leader = false;
-	if (last_checkpoint_lsn >= 0) {
+	if (checkpoint != NULL) {
 		/* Recover the instance from the local directory */
 		local_recovery(&instance_uuid, &replicaset_uuid,
-			       &last_checkpoint_vclock);
+			       &checkpoint->vclock);
 	} else {
 		/* Bootstrap a new master */
 		bootstrap(&instance_uuid, &replicaset_uuid,
@@ -2151,7 +2156,8 @@ end:
 	if (rc)
 		engine_abort_checkpoint();
 	else
-		gc_run();
+		gc_add_checkpoint(&vclock);
+
 	latch_unlock(&schema_lock);
 	box_checkpoint_is_in_progress = false;
 	return rc;
@@ -2165,20 +2171,20 @@ box_backup_start(int checkpoint_idx, box_backup_cb cb, void *cb_arg)
 		diag_set(ClientError, ER_BACKUP_IN_PROGRESS);
 		return -1;
 	}
-	const struct vclock *vclock;
-	struct checkpoint_iterator it;
-	checkpoint_iterator_init(&it);
-	do {
-		vclock = checkpoint_iterator_prev(&it);
-		if (vclock == NULL) {
-			diag_set(ClientError, ER_MISSING_SNAPSHOT);
-			return -1;
-		}
-	} while (checkpoint_idx-- > 0);
-	backup_gc = gc_consumer_register(vclock, GC_CONSUMER_ALL, "backup");
+	struct gc_checkpoint *checkpoint;
+	gc_foreach_checkpoint_reverse(checkpoint) {
+		if (checkpoint_idx-- == 0)
+			break;
+	}
+	if (checkpoint_idx >= 0) {
+		diag_set(ClientError, ER_MISSING_SNAPSHOT);
+		return -1;
+	}
+	backup_gc = gc_consumer_register(&checkpoint->vclock,
+					 GC_CONSUMER_ALL, "backup");
 	if (backup_gc == NULL)
 		return -1;
-	int rc = engine_backup(vclock, cb, cb_arg);
+	int rc = engine_backup(&checkpoint->vclock, cb, cb_arg);
 	if (rc != 0) {
 		gc_consumer_unregister(backup_gc);
 		backup_gc = NULL;
diff --git a/src/box/checkpoint.c b/src/box/checkpoint.c
deleted file mode 100644
index cc32e75c..00000000
--- a/src/box/checkpoint.c
+++ /dev/null
@@ -1,72 +0,0 @@
-/*
- * Copyright 2010-2017, Tarantool AUTHORS, please see AUTHORS file.
- *
- * Redistribution and use in source and binary forms, with or
- * without modification, are permitted provided that the following
- * conditions are met:
- *
- * 1. Redistributions of source code must retain the above
- *    copyright notice, this list of conditions and the
- *    following disclaimer.
- *
- * 2. Redistributions in binary form must reproduce the above
- *    copyright notice, this list of conditions and the following
- *    disclaimer in the documentation and/or other materials
- *    provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY AUTHORS ``AS IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
- * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
- * AUTHORS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
- * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
- * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
- * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
- * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
- * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- */
-#include "checkpoint.h"
-
-#include <stdbool.h>
-#include <stdint.h>
-
-#include "engine.h"
-#include "memtx_engine.h"
-
-int64_t
-checkpoint_last(struct vclock *vclock)
-{
-	struct memtx_engine *memtx;
-	memtx = (struct memtx_engine *)engine_by_name("memtx");
-	assert(memtx != NULL);
-	return xdir_last_vclock(&memtx->snap_dir, vclock);
-}
-
-const struct vclock *
-checkpoint_iterator_next(struct checkpoint_iterator *it)
-{
-	struct memtx_engine *memtx;
-	memtx = (struct memtx_engine *)engine_by_name("memtx");
-	assert(memtx != NULL);
-	it->curr = it->curr == NULL ?
-		vclockset_first(&memtx->snap_dir.index) :
-		vclockset_next(&memtx->snap_dir.index,
-			       (struct vclock *)it->curr);
-	return it->curr;
-}
-
-const struct vclock *
-checkpoint_iterator_prev(struct checkpoint_iterator *it)
-{
-	struct memtx_engine *memtx;
-	memtx = (struct memtx_engine *)engine_by_name("memtx");
-	assert(memtx != NULL);
-	it->curr = it->curr == NULL ?
-		vclockset_last(&memtx->snap_dir.index) :
-		vclockset_prev(&memtx->snap_dir.index,
-			       (struct vclock *)it->curr);
-	return it->curr;
-}
diff --git a/src/box/checkpoint.h b/src/box/checkpoint.h
deleted file mode 100644
index 00a1e705..00000000
--- a/src/box/checkpoint.h
+++ /dev/null
@@ -1,97 +0,0 @@
-#ifndef TARANTOOL_BOX_CHECKPOINT_H_INCLUDED
-#define TARANTOOL_BOX_CHECKPOINT_H_INCLUDED
-/*
- * Copyright 2010-2017, Tarantool AUTHORS, please see AUTHORS file.
- *
- * Redistribution and use in source and binary forms, with or
- * without modification, are permitted provided that the following
- * conditions are met:
- *
- * 1. Redistributions of source code must retain the above
- *    copyright notice, this list of conditions and the
- *    following disclaimer.
- *
- * 2. Redistributions in binary form must reproduce the above
- *    copyright notice, this list of conditions and the following
- *    disclaimer in the documentation and/or other materials
- *    provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY AUTHORS ``AS IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
- * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
- * AUTHORS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
- * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
- * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
- * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
- * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
- * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- */
-
-#include <stdbool.h>
-#include <stddef.h>
-#include <stdint.h>
-
-/**
- * This module implements a simple API for working with checkpoints.
- * As checkpoints are, in fact, memtx snapshots, functions exported
- * by this module are C wrappers around corresponding memtx_engine
- * methods.
- */
-
-#if defined(__cplusplus)
-extern "C" {
-#endif /* defined(__cplusplus) */
-
-struct vclock;
-
-/**
- * Return LSN and vclock (unless @vclock is NULL) of the most
- * recent checkpoint or -1 if there is no checkpoint.
- */
-int64_t
-checkpoint_last(struct vclock *vclock);
-
-/** Iterator over all existing checkpoints. */
-struct checkpoint_iterator {
-	const struct vclock *curr;
-};
-
-/**
- * Init a checkpoint iterator. The iterator is valid as long
- * as the caller doesn't yield.
- */
-static inline void
-checkpoint_iterator_init(struct checkpoint_iterator *it)
-{
-	it->curr = NULL;
-}
-
-/**
- * Iterate to the next checkpoint. Return NULL if the current
- * checkpoint is the most recent one.
- *
- * If called on the last iteration, this function positions
- * the iterator to the oldest checkpoint.
- */
-const struct vclock *
-checkpoint_iterator_next(struct checkpoint_iterator *it);
-
-/**
- * Iterate to the previous checkpoint. Return NULL if the current
- * checkpoint is the oldest one.
- *
- * If called on the first iteration, this function positions
- * the iterator to the newest checkpoint.
- */
-const struct vclock *
-checkpoint_iterator_prev(struct checkpoint_iterator *it);
-
-#if defined(__cplusplus)
-} /* extern "C" */
-#endif /* defined(__cplusplus) */
-
-#endif /* TARANTOOL_BOX_CHECKPOINT_H_INCLUDED */
diff --git a/src/box/gc.c b/src/box/gc.c
index dca278af..e6951f4c 100644
--- a/src/box/gc.c
+++ b/src/box/gc.c
@@ -32,7 +32,10 @@
 
 #include <trivia/util.h>
 
+#include <assert.h>
+#include <limits.h>
 #include <stdarg.h>
+#include <stdbool.h>
 #include <stdint.h>
 #include <stdlib.h>
 #include <stdio.h>
@@ -45,7 +48,6 @@
 #include "say.h"
 #include "latch.h"
 #include "vclock.h"
-#include "checkpoint.h"
 #include "engine.h"		/* engine_collect_garbage() */
 #include "wal.h"		/* wal_collect_garbage() */
 
@@ -75,6 +77,10 @@ rb_gen(MAYBE_UNUSED static inline, gc_tree_, gc_tree_t,
 void
 gc_init(void)
 {
+	/* Don't delete any files until recovery is complete. */
+	gc.min_checkpoint_count = INT_MAX;
+
+	rlist_create(&gc.checkpoints);
 	vclock_create(&gc.wal_vclock);
 	vclock_create(&gc.checkpoint_vclock);
 	gc_tree_new(&gc.consumers);
@@ -84,6 +90,12 @@ gc_init(void)
 void
 gc_free(void)
 {
+	/* Free checkpoints. */
+	struct gc_checkpoint *checkpoint, *next_checkpoint;
+	rlist_foreach_entry_safe(checkpoint, &gc.checkpoints, in_checkpoints,
+				 next_checkpoint) {
+		free(checkpoint);
+	}
 	/* Free all registered consumers. */
 	struct gc_consumer *consumer = gc_tree_first(&gc.consumers);
 	while (consumer != NULL) {
@@ -105,12 +117,14 @@ gc_tree_first_checkpoint(gc_tree_t *consumers)
 	return consumer;
 }
 
-void
+/**
+ * Invoke garbage collection in order to remove files left
+ * from old checkpoints. The number of checkpoints saved by
+ * this function is specified by box.cfg.checkpoint_count.
+ */
+static void
 gc_run(void)
 {
-	int min_checkpoint_count = gc.min_checkpoint_count;
-	assert(min_checkpoint_count > 0);
-
 	/* Look up the consumer that uses the oldest WAL. */
 	struct gc_consumer *leftmost = gc_tree_first(&gc.consumers);
 	/* Look up the consumer that uses the oldest checkpoint. */
@@ -126,20 +140,25 @@ gc_run(void)
 	struct vclock gc_checkpoint_vclock;
 	vclock_create(&gc_checkpoint_vclock);
 
-	struct checkpoint_iterator checkpoints;
-	checkpoint_iterator_init(&checkpoints);
-
-	const struct vclock *vclock;
-	while ((vclock = checkpoint_iterator_prev(&checkpoints)) != NULL) {
-		if (--min_checkpoint_count > 0)
-			continue;
+	struct gc_checkpoint *checkpoint = NULL;
+	while (true) {
+		checkpoint = rlist_first_entry(&gc.checkpoints,
+				struct gc_checkpoint, in_checkpoints);
+		vclock_copy(&gc_checkpoint_vclock, &checkpoint->vclock);
+		if (gc.checkpoint_count <= gc.min_checkpoint_count)
+			break;
 		if (leftmost_checkpoint != NULL &&
-		    vclock_sum(&leftmost_checkpoint->vclock) < vclock_sum(vclock))
-			continue;
-		vclock_copy(&gc_checkpoint_vclock, vclock);
-		break;
+		    vclock_sum(&checkpoint->vclock) >=
+		    vclock_sum(&leftmost_checkpoint->vclock))
+			break; /* checkpoint is in use */
+		rlist_del_entry(checkpoint, in_checkpoints);
+		free(checkpoint);
+		gc.checkpoint_count--;
 	}
 
+	/* At least one checkpoint must always be available. */
+	assert(checkpoint != NULL);
+
 	struct vclock gc_wal_vclock;
 	if (leftmost != NULL &&
 	    vclock_sum(&leftmost->vclock) < vclock_sum(&gc_checkpoint_vclock))
@@ -186,6 +205,39 @@ gc_set_min_checkpoint_count(int min_checkpoint_count)
 	gc.min_checkpoint_count = min_checkpoint_count;
 }
 
+void
+gc_add_checkpoint(const struct vclock *vclock)
+{
+	struct gc_checkpoint *last_checkpoint = gc_last_checkpoint();
+	if (last_checkpoint != NULL &&
+	    vclock_sum(&last_checkpoint->vclock) == vclock_sum(vclock)) {
+		/*
+		 * No new checkpoint was actually created.
+		 * Rerun the garbage collector to delete old
+		 * files in case box.cfg.checkpoint_count
+		 * was changed.
+		 */
+		gc_run();
+		return;
+	}
+	assert(last_checkpoint == NULL ||
+	       vclock_sum(&last_checkpoint->vclock) < vclock_sum(vclock));
+
+	struct gc_checkpoint *checkpoint = calloc(1, sizeof(*checkpoint));
+	/*
+	 * This function is called after a checkpoint is written
+	 * to disk so it can't fail.
+	 */
+	if (checkpoint == NULL)
+		panic("out of memory");
+
+	vclock_copy(&checkpoint->vclock, vclock);
+	rlist_add_tail_entry(&gc.checkpoints, checkpoint, in_checkpoints);
+	gc.checkpoint_count++;
+
+	gc_run();
+}
+
 struct gc_consumer *
 gc_consumer_register(const struct vclock *vclock, enum gc_consumer_type type,
 		     const char *format, ...)
diff --git a/src/box/gc.h b/src/box/gc.h
index 418f8d5e..e26b1017 100644
--- a/src/box/gc.h
+++ b/src/box/gc.h
@@ -32,6 +32,7 @@
  */
 
 #include <stddef.h>
+#include <small/rlist.h>
 
 #include "vclock.h"
 #include "latch.h"
@@ -55,6 +56,17 @@ enum gc_consumer_type {
 typedef rb_node(struct gc_consumer) gc_node_t;
 
 /**
+ * Garbage collector keeps track of all preserved checkpoints.
+ * The following structure represents a checkpoint.
+ */
+struct gc_checkpoint {
+	/** Link in gc_state::checkpoints. */
+	struct rlist in_checkpoints;
+	/** VClock of the checkpoint. */
+	struct vclock vclock;
+};
+
+/**
  * The object of this type is used to prevent garbage
  * collection from removing files that are still in use.
  */
@@ -80,6 +92,17 @@ struct gc_state {
 	 * Configured by box.cfg.checkpoint_count.
 	 */
 	int min_checkpoint_count;
+	/**
+	 * Number of preserved checkpoints. May be greater than
+	 * @min_checkpoint_count, because some checkpoints may
+	 * be in use by replication or backup.
+	 */
+	int checkpoint_count;
+	/**
+	 * List of preserved checkpoints. New checkpoints are added
+	 * to the tail. Linked by gc_checkpoint::in_checkpoints.
+	 */
+	struct rlist checkpoints;
 	/** Max vclock WAL garbage collection has been called for. */
 	struct vclock wal_vclock;
 	/** Max vclock checkpoint garbage collection has been called for. */
@@ -95,6 +118,35 @@ struct gc_state {
 extern struct gc_state gc;
 
 /**
+ * Iterate over all checkpoints tracked by the garbage collector,
+ * starting from the oldest and ending with the newest.
+ */
+#define gc_foreach_checkpoint(checkpoint) \
+	rlist_foreach_entry(checkpoint, &gc.checkpoints, in_checkpoints)
+
+/**
+ * Iterate over all checkpoints tracked by the garbage collector
+ * in the reverse order, that is starting from the newest and
+ * ending with the oldest.
+ */
+#define gc_foreach_checkpoint_reverse(checkpoint) \
+	rlist_foreach_entry_reverse(checkpoint, &gc.checkpoints, in_checkpoints)
+
+/**
+ * Return the last (newest) checkpoint known to the garbage
+ * collector. If there's no checkpoint, return NULL.
+ */
+static inline struct gc_checkpoint *
+gc_last_checkpoint(void)
+{
+	if (rlist_empty(&gc.checkpoints))
+		return NULL;
+
+	return rlist_last_entry(&gc.checkpoints, struct gc_checkpoint,
+				in_checkpoints);
+}
+
+/**
  * Initialize the garbage collection state.
  */
 void
@@ -107,14 +159,6 @@ void
 gc_free(void);
 
 /**
- * Invoke garbage collection in order to remove files left
- * from old checkpoints. The number of checkpoints saved by
- * this function is specified by box.cfg.checkpoint_count.
- */
-void
-gc_run(void);
-
-/**
  * Update the minimal number of checkpoints to preserve.
  * Called when box.cfg.checkpoint_count is updated.
  *
@@ -126,6 +170,14 @@ void
 gc_set_min_checkpoint_count(int min_checkpoint_count);
 
 /**
+ * Track a new checkpoint in the garbage collector state.
+ * Note, this function may run garbage collector to remove
+ * old checkpoints.
+ */
+void
+gc_add_checkpoint(const struct vclock *vclock);
+
+/**
  * Register a consumer.
  *
  * This will stop garbage collection of objects newer than
diff --git a/src/box/lua/info.c b/src/box/lua/info.c
index 85b21c65..97d5aba3 100644
--- a/src/box/lua/info.c
+++ b/src/box/lua/info.c
@@ -47,7 +47,6 @@
 #include "box/replication.h"
 #include "box/info.h"
 #include "box/gc.h"
-#include "box/checkpoint.h"
 #include "box/engine.h"
 #include "box/vinyl.h"
 #include "main.h"
@@ -363,22 +362,19 @@ static int
 lbox_info_gc_call(struct lua_State *L)
 {
 	int count;
-	const struct vclock *vclock;
 
 	lua_newtable(L);
 
 	lua_pushstring(L, "checkpoints");
 	lua_newtable(L);
 
-	struct checkpoint_iterator checkpoints;
-	checkpoint_iterator_init(&checkpoints);
-
 	count = 0;
-	while ((vclock = checkpoint_iterator_next(&checkpoints)) != NULL) {
+	struct gc_checkpoint *checkpoint;
+	gc_foreach_checkpoint(checkpoint) {
 		lua_createtable(L, 0, 1);
 
 		lua_pushstring(L, "signature");
-		luaL_pushint64(L, vclock_sum(vclock));
+		luaL_pushint64(L, vclock_sum(&checkpoint->vclock));
 		lua_settable(L, -3);
 
 		lua_rawseti(L, -2, ++count);
diff --git a/src/box/memtx_engine.c b/src/box/memtx_engine.c
index 1f80ce54..ae1f5a0e 100644
--- a/src/box/memtx_engine.c
+++ b/src/box/memtx_engine.c
@@ -1046,6 +1046,13 @@ memtx_engine_new(const char *snap_dirname, bool force_recovery,
 		xlog_cursor_close(&cursor, false);
 	}
 
+	/* Apprise the garbage collector of available checkpoints. */
+	for (struct vclock *vclock = vclockset_first(&memtx->snap_dir.index);
+	     vclock != NULL;
+	     vclock = vclockset_next(&memtx->snap_dir.index, vclock)) {
+		gc_add_checkpoint(vclock);
+	}
+
 	stailq_create(&memtx->gc_queue);
 	memtx->gc_fiber = fiber_new("memtx.gc", memtx_engine_gc_f);
 	if (memtx->gc_fiber == NULL)
diff --git a/src/box/vinyl.c b/src/box/vinyl.c
index fd24f9b5..acfe86d1 100644
--- a/src/box/vinyl.c
+++ b/src/box/vinyl.c
@@ -70,7 +70,6 @@
 #include "info.h"
 #include "column_mask.h"
 #include "trigger.h"
-#include "checkpoint.h"
 #include "session.h"
 #include "wal.h" /* wal_mode() */
 
@@ -3304,7 +3303,7 @@ vinyl_engine_collect_garbage(struct engine *engine, int64_t lsn)
 	vy_log_collect_garbage(lsn);
 
 	/* Cleanup run files. */
-	int64_t signature = checkpoint_last(NULL);
+	int64_t signature = vy_log_signature();
 	struct vy_recovery *recovery = vy_recovery_new(signature, 0);
 	if (recovery == NULL) {
 		say_error("failed to recover vylog for garbage collection");
diff --git a/src/box/vy_scheduler.c b/src/box/vy_scheduler.c
index 2f85424a..eab3f6c5 100644
--- a/src/box/vy_scheduler.c
+++ b/src/box/vy_scheduler.c
@@ -39,7 +39,6 @@
 #include <small/rlist.h>
 #include <tarantool_ev.h>
 
-#include "checkpoint.h"
 #include "diag.h"
 #include "errcode.h"
 #include "errinj.h"
-- 
2.11.0