[tarantool-patches] [PATCH v1 1/1] box: restore region after box.snapshot()

[imeevma@tarantool.org]

Before this patch region wasn't restored after box.snapshot() so
some tests fail due to "memory leak". After this patch region will
be restored using region_truncate(). It could be done by cleaning
memory in case there wasn't active transaction but it seems like
region_truncate() is more universal.

Closes #3732
---
Issue: https://github.com/tarantool/tarantool/issues/3732
Branch: https://github.com/tarantool/tarantool/tree/imeevma/gh-3732-restore_region_after_box_snapshot

 src/box/box.cc                |  2 ++
 test/engine/snapshot.result   | 35 +++++++++++++++++++++++++++++++++++
 test/engine/snapshot.test.lua | 17 +++++++++++++++++
 3 files changed, 54 insertions(+)

diff --git a/src/box/box.cc b/src/box/box.cc
index c4b4fb4..0d27aa2 100644
--- a/src/box/box.cc
+++ b/src/box/box.cc
@@ -2157,6 +2157,7 @@ box_checkpoint()
 	if (! is_box_configured)
 		return 0;
 	int rc = 0;
+	size_t used = region_used(&fiber()->gc);
 	if (box_checkpoint_is_in_progress) {
 		diag_set(ClientError, ER_CHECKPOINT_IN_PROGRESS);
 		return -1;
@@ -2181,6 +2182,7 @@ end:
 
 	latch_unlock(&schema_lock);
 	box_checkpoint_is_in_progress = false;
+	region_truncate(&fiber()->gc, used);
 	return rc;
 }
 
diff --git a/test/engine/snapshot.result b/test/engine/snapshot.result
index a5aa08d..42009c2 100644
--- a/test/engine/snapshot.result
+++ b/test/engine/snapshot.result
@@ -238,3 +238,38 @@ box.space.test.index.secondary:select{}
 box.space.test:drop()
 ---
 ...
+--
+-- sql: fix sql/gh-3199-no-mem-leaks.test.lua
+-- One of the reason why this test failed - box.snapshot didn't
+-- free region.
+--
+fiber = require('fiber')
+---
+...
+-- Should be 0.
+fiber.info()[fiber.self().id()].memory.used
+---
+- 0
+...
+box.snapshot()
+---
+- ok
+...
+-- Should be 0.
+fiber.info()[fiber.self().id()].memory.used
+---
+- 0
+...
+box.snapshot()
+---
+- ok
+...
+box.snapshot()
+---
+- ok
+...
+-- Should be 0.
+fiber.info()[fiber.self().id()].memory.used
+---
+- 0
+...
diff --git a/test/engine/snapshot.test.lua b/test/engine/snapshot.test.lua
index 4bbbe40..2a32280 100644
--- a/test/engine/snapshot.test.lua
+++ b/test/engine/snapshot.test.lua
@@ -41,3 +41,20 @@ box.space.test:select{}
 box.space.test.index.primary:select{}
 box.space.test.index.secondary:select{}
 box.space.test:drop()
+
+--
+-- sql: fix sql/gh-3199-no-mem-leaks.test.lua
+-- One of the reason why this test failed - box.snapshot didn't
+-- free region.
+--
+
+fiber = require('fiber')
+-- Should be 0.
+fiber.info()[fiber.self().id()].memory.used
+box.snapshot()
+-- Should be 0.
+fiber.info()[fiber.self().id()].memory.used
+box.snapshot()
+box.snapshot()
+-- Should be 0.
+fiber.info()[fiber.self().id()].memory.used
-- 
2.7.4