[Tarantool-patches] [PATCH v2 14/16] sql: introduce cache for prepared statemets
Nikita Pettik
korablev at tarantool.org
Thu Nov 21 00:28:13 MSK 2019
This patch introduces cache (as data structure) to handle prepared
statements and a set of interface functions (insert, delete, find) to
operate on it. Cache under the hood uses LRU eviction policy. It is
implemented as a hash table with string keys (which contain original SQL
statements) and prepared statements (struct sql_stmt which is an alias
for struct Vdbe) as values. To realise LRU strategy we maintain list of
nodes: head is the newest prepared statement, tail a candidate to be
evicted. Size of cache is regulated via box.cfg{sql_cache_size}
parameter. Cache is global to all sessions. To erase session manually,
one can set its size to 0. Default cache size is assumed to be 5 Mb.
Part of #2592
---
src/box/CMakeLists.txt | 1 +
src/box/box.cc | 20 +++++
src/box/box.h | 1 +
src/box/errcode.h | 1 +
src/box/lua/cfg.cc | 12 +++
src/box/lua/load_cfg.lua | 3 +
src/box/prep_stmt.c | 186 ++++++++++++++++++++++++++++++++++++++++
src/box/prep_stmt.h | 112 ++++++++++++++++++++++++
src/box/session.cc | 1 +
src/box/sql.c | 3 +
test/app-tap/init_script.result | 37 ++++----
test/box/admin.result | 2 +
test/box/cfg.result | 7 ++
test/box/cfg.test.lua | 1 +
test/box/misc.result | 1 +
15 files changed, 370 insertions(+), 18 deletions(-)
create mode 100644 src/box/prep_stmt.c
create mode 100644 src/box/prep_stmt.h
diff --git a/src/box/CMakeLists.txt b/src/box/CMakeLists.txt
index 5cd5cba81..8be3d982d 100644
--- a/src/box/CMakeLists.txt
+++ b/src/box/CMakeLists.txt
@@ -126,6 +126,7 @@ add_library(box STATIC
sql.c
bind.c
execute.c
+ prep_stmt.c
wal.c
call.c
merger.c
diff --git a/src/box/box.cc b/src/box/box.cc
index b119c927b..7d0b36f13 100644
--- a/src/box/box.cc
+++ b/src/box/box.cc
@@ -74,6 +74,7 @@
#include "call.h"
#include "func.h"
#include "sequence.h"
+#include "prep_stmt.h"
static char status[64] = "unknown";
@@ -599,6 +600,15 @@ box_check_vinyl_options(void)
}
}
+static void
+box_check_sql_cache_size(int size)
+{
+ if (size < 0) {
+ tnt_raise(ClientError, ER_CFG, "sql_cache_size",
+ "must be non-negative");
+ }
+}
+
void
box_check_config()
{
@@ -620,6 +630,7 @@ box_check_config()
box_check_memtx_memory(cfg_geti64("memtx_memory"));
box_check_memtx_min_tuple_size(cfg_geti64("memtx_min_tuple_size"));
box_check_vinyl_options();
+ box_check_sql_cache_size(cfg_geti("sql_cache_size"));
}
/*
@@ -886,6 +897,14 @@ box_set_net_msg_max(void)
IPROTO_FIBER_POOL_SIZE_FACTOR);
}
+void
+box_set_prepared_stmt_cache_size(void)
+{
+ int cache_sz = cfg_geti("sql_cache_size");
+ box_check_sql_cache_size(cache_sz);
+ sql_prepared_stmt_cache_set_size(cache_sz);
+}
+
/* }}} configuration bindings */
/**
@@ -2096,6 +2115,7 @@ box_cfg_xc(void)
box_check_instance_uuid(&instance_uuid);
box_check_replicaset_uuid(&replicaset_uuid);
+ box_set_prepared_stmt_cache_size();
box_set_net_msg_max();
box_set_readahead();
box_set_too_long_threshold();
diff --git a/src/box/box.h b/src/box/box.h
index ccd527bd5..f2e88c8a9 100644
--- a/src/box/box.h
+++ b/src/box/box.h
@@ -235,6 +235,7 @@ void box_set_replication_sync_lag(void);
void box_set_replication_sync_timeout(void);
void box_set_replication_skip_conflict(void);
void box_set_net_msg_max(void);
+void box_set_prepared_stmt_cache_size(void);
extern "C" {
#endif /* defined(__cplusplus) */
diff --git a/src/box/errcode.h b/src/box/errcode.h
index c660b1c70..ee44f61b3 100644
--- a/src/box/errcode.h
+++ b/src/box/errcode.h
@@ -258,6 +258,7 @@ struct errcode_record {
/*203 */_(ER_BOOTSTRAP_READONLY, "Trying to bootstrap a local read-only instance as master") \
/*204 */_(ER_SQL_FUNC_WRONG_RET_COUNT, "SQL expects exactly one argument returned from %s, got %d")\
/*205 */_(ER_FUNC_INVALID_RETURN_TYPE, "Function '%s' returned value of invalid type: expected %s got %s") \
+ /*206 */_(ER_SQL_PREPARE, "Failed to prepare SQL statement: %s") \
/*
* !IMPORTANT! Please follow instructions at start of the file
diff --git a/src/box/lua/cfg.cc b/src/box/lua/cfg.cc
index 4884ce013..42070fe49 100644
--- a/src/box/lua/cfg.cc
+++ b/src/box/lua/cfg.cc
@@ -274,6 +274,17 @@ lbox_cfg_set_net_msg_max(struct lua_State *L)
return 0;
}
+static int
+lbox_set_prepared_stmt_cache_size(struct lua_State *L)
+{
+ try {
+ box_set_prepared_stmt_cache_size();
+ } catch (Exception *) {
+ luaT_error(L);
+ }
+ return 0;
+}
+
static int
lbox_cfg_set_worker_pool_threads(struct lua_State *L)
{
@@ -378,6 +389,7 @@ box_lua_cfg_init(struct lua_State *L)
{"cfg_set_replication_sync_timeout", lbox_cfg_set_replication_sync_timeout},
{"cfg_set_replication_skip_conflict", lbox_cfg_set_replication_skip_conflict},
{"cfg_set_net_msg_max", lbox_cfg_set_net_msg_max},
+ {"cfg_set_sql_cache_size", lbox_set_prepared_stmt_cache_size},
{NULL, NULL}
};
diff --git a/src/box/lua/load_cfg.lua b/src/box/lua/load_cfg.lua
index 85617c8f0..4463f989c 100644
--- a/src/box/lua/load_cfg.lua
+++ b/src/box/lua/load_cfg.lua
@@ -81,6 +81,7 @@ local default_cfg = {
feedback_host = "https://feedback.tarantool.io",
feedback_interval = 3600,
net_msg_max = 768,
+ sql_cache_size = 5 * 1024 * 1024,
}
-- types of available options
@@ -144,6 +145,7 @@ local template_cfg = {
feedback_host = 'string',
feedback_interval = 'number',
net_msg_max = 'number',
+ sql_cache_size = 'number',
}
local function normalize_uri(port)
@@ -250,6 +252,7 @@ local dynamic_cfg = {
instance_uuid = check_instance_uuid,
replicaset_uuid = check_replicaset_uuid,
net_msg_max = private.cfg_set_net_msg_max,
+ sql_cache_size = private.cfg_set_sql_cache_size,
}
--
diff --git a/src/box/prep_stmt.c b/src/box/prep_stmt.c
new file mode 100644
index 000000000..fe3b8244e
--- /dev/null
+++ b/src/box/prep_stmt.c
@@ -0,0 +1,186 @@
+/*
+ * Copyright 2010-2019, 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 <COPYRIGHT HOLDER> ``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
+ * <COPYRIGHT HOLDER> 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 "prep_stmt.h"
+
+#include "assoc.h"
+#include "error.h"
+#include "execute.h"
+#include "session.h"
+
+/** Default cache size is 5 Mb. */
+size_t prep_stmt_cache_size = 5 * 1024 * 1024;
+
+static struct prep_stmt_cache prep_stmt_cache;
+
+void
+sql_prepared_stmt_cache_init()
+{
+ prep_stmt_cache.hash = mh_strnptr_new();
+ if (prep_stmt_cache.hash == NULL)
+ panic("out of memory");
+ prep_stmt_cache.mem_quota = prep_stmt_cache_size;
+ prep_stmt_cache.mem_used = 0;
+ rlist_create(&prep_stmt_cache.cache_lru);
+}
+
+static size_t
+sql_cache_node_sizeof(struct sql_stmt *stmt)
+{
+ return sql_stmt_sizeof(stmt) + sizeof(struct stmt_cache_node *);
+}
+
+static void
+sql_cache_node_delete(struct prep_stmt_cache *cache,
+ struct stmt_cache_node *node)
+{
+ cache->mem_used -= sql_cache_node_sizeof(node->stmt);
+ rlist_del(&node->in_lru);
+ sql_finalize(node->stmt);
+ TRASH(node);
+ free(node);
+}
+
+void
+sql_prepared_stmt_cache_delete(struct stmt_cache_node *node)
+{
+ struct prep_stmt_cache *cache = &prep_stmt_cache;
+ const char *sql_str = sql_stmt_query_str(node->stmt);
+ mh_int_t hash_id =
+ mh_strnptr_find_inp(cache->hash, sql_str, strlen(sql_str));
+ assert(hash_id != mh_end(cache->hash));
+ mh_strnptr_del(cache->hash, hash_id, NULL);
+ sql_cache_node_delete(cache, node);
+}
+
+void
+sql_cache_stmt_refresh(struct stmt_cache_node *node)
+{
+ rlist_move_entry(&prep_stmt_cache.cache_lru, node, in_lru);
+}
+
+static void
+sql_prepared_stmt_cache_gc()
+{
+ if (rlist_empty(&prep_stmt_cache.cache_lru)) {
+ assert(prep_stmt_cache.mem_used == 0);
+ return;
+ }
+ struct stmt_cache_node *node =
+ rlist_last_entry(&prep_stmt_cache.cache_lru, struct stmt_cache_node,
+ in_lru);
+ /*
+ * TODO: instead of following simple LRU rule it could turn
+ * out to be reasonable to also account value of reference
+ * counters.
+ */
+ sql_prepared_stmt_cache_delete(node);
+}
+
+/**
+ * Allocate new cache node containing given prepared statement.
+ * Add it to the LRU cache list. Account cache size enlargement.
+ */
+static struct stmt_cache_node *
+sql_cache_node_new(struct sql_stmt *stmt)
+{
+ struct stmt_cache_node *node = malloc(sizeof(*node));
+ if (node == NULL) {
+ diag_set(OutOfMemory, sizeof(*node), "malloc",
+ "struct stmt_cache_node");
+ return NULL;
+ }
+ node->stmt = stmt;
+ rlist_add(&prep_stmt_cache.cache_lru, &node->in_lru);
+ prep_stmt_cache.mem_used += sql_cache_node_sizeof(stmt);
+ return node;
+}
+
+/**
+ * Return true if used memory (accounting new node) for SQL
+ * prepared statement cache does not exceed the limit.
+ */
+static bool
+sql_cache_check_new_node_size(size_t size)
+{
+ return prep_stmt_cache.mem_used + size <= prep_stmt_cache.mem_quota;
+}
+
+int
+sql_prepared_stmt_cache_insert(struct sql_stmt *stmt)
+{
+ assert(stmt != NULL);
+ struct prep_stmt_cache *cache = &prep_stmt_cache;
+ size_t new_node_size = sql_cache_node_sizeof(stmt);
+ if (new_node_size > prep_stmt_cache.mem_quota) {
+ diag_set(ClientError, ER_SQL_PREPARE, "size of statement "\
+ "exceeds cache memory limit. Please, increase SQL "\
+ "cache size");
+ return -1;
+ }
+ while (! sql_cache_check_new_node_size(new_node_size))
+ sql_prepared_stmt_cache_gc();
+ struct mh_strnptr_t *hash = cache->hash;
+ const char *sql_str = sql_stmt_query_str(stmt);
+ assert(sql_prepared_stmt_cache_find(sql_str) == NULL);
+ struct stmt_cache_node *cache_node = sql_cache_node_new(stmt);
+ if (cache_node == NULL)
+ return -1;
+ uint32_t str_hash = mh_strn_hash(sql_str, strlen(sql_str));
+ const struct mh_strnptr_node_t hash_node = { sql_str, strlen(sql_str),
+ str_hash, cache_node };
+ struct mh_strnptr_node_t *old_node = NULL;
+ mh_int_t i = mh_strnptr_put(hash, &hash_node, &old_node, NULL);
+ if (i == mh_end(hash)) {
+ sql_cache_node_delete(cache, cache_node);
+ diag_set(OutOfMemory, 0, "mh_strnptr_put", "mh_strnptr_node");
+ return -1;
+ }
+ assert(old_node == NULL);
+ return 0;
+}
+
+struct stmt_cache_node *
+sql_prepared_stmt_cache_find(const char *sql_str)
+{
+ struct mh_strnptr_t *hash = prep_stmt_cache.hash;
+ mh_int_t stmt = mh_strnptr_find_inp(hash, sql_str, strlen(sql_str));
+ if (stmt == mh_end(hash))
+ return NULL;
+ return mh_strnptr_node(hash, stmt)->val;
+}
+
+void
+sql_prepared_stmt_cache_set_size(size_t size)
+{
+ prep_stmt_cache.mem_quota = size;
+ while (prep_stmt_cache.mem_used > size)
+ sql_prepared_stmt_cache_gc();
+}
diff --git a/src/box/prep_stmt.h b/src/box/prep_stmt.h
new file mode 100644
index 000000000..31f3ff52b
--- /dev/null
+++ b/src/box/prep_stmt.h
@@ -0,0 +1,112 @@
+#ifndef INCLUDES_PREP_STMT_H
+#define INCLUDES_PREP_STMT_H
+/*
+ * Copyright 2010-2019, 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 <COPYRIGHT HOLDER> ``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
+ * <COPYRIGHT HOLDER> 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 <stdint.h>
+#include <stdio.h>
+
+#include "small/rlist.h"
+
+#if defined(__cplusplus)
+extern "C" {
+#endif
+
+extern size_t prep_stmt_cache_size;
+
+/**
+ * Global prepared statement cache which follows LRU
+ * eviction policy. Implemented as hash <str : stmt>
+ * and double linked list.
+ */
+struct prep_stmt_cache {
+ /** Size of memory currently occupied by prepared statements. */
+ size_t mem_used;
+ /**
+ * Max memory size that can be used for cache.
+ */
+ size_t mem_quota;
+ /** Query hash -> struct prepared_stmt hash.*/
+ struct mh_strnptr_t *hash;
+ struct rlist cache_lru;
+};
+
+struct stmt_cache_node {
+ /** Prepared statement itself. */
+ struct sql_stmt *stmt;
+ /**
+ * Link to the next node. Head is the newest, tail is
+ * a candidate to be evicted.
+ */
+ struct rlist in_lru;
+};
+
+struct sql_stmt;
+
+/**
+ * Initialize global cache for prepared statements. Called once
+ * in sql_init().
+ */
+void
+sql_prepared_stmt_cache_init();
+
+/** Remove statement node from cache and release all resources. */
+void
+sql_prepared_stmt_cache_delete(struct stmt_cache_node *node);
+
+/**
+ * Account LRU cache node as the newest one (i.e. move to the HEAD
+ * of LRU list).
+ */
+void
+sql_cache_stmt_refresh(struct stmt_cache_node *node);
+
+/**
+ * Save prepared statement to the prepared statement cache.
+ * Account cache size change. If the cache is full (i.e. memory
+ * quota is exceeded) diag error is raised. In case of success
+ * return id of prepared statement via output parameter @id.
+ */
+int
+sql_prepared_stmt_cache_insert(struct sql_stmt *stmt);
+
+/** Find entry by SQL string. In case of search fails it returns NULL. */
+struct stmt_cache_node *
+sql_prepared_stmt_cache_find(const char *sql_str);
+
+/** Set @prep_stmt_cache_size value. */
+void
+sql_prepared_stmt_cache_set_size(size_t size);
+
+#if defined(__cplusplus)
+} /* extern "C" { */
+#endif
+
+#endif
diff --git a/src/box/session.cc b/src/box/session.cc
index 461d1cf25..fe33ae6b6 100644
--- a/src/box/session.cc
+++ b/src/box/session.cc
@@ -36,6 +36,7 @@
#include "user.h"
#include "error.h"
#include "tt_static.h"
+#include "execute.h"
const char *session_type_strs[] = {
"background",
diff --git a/src/box/sql.c b/src/box/sql.c
index f1df55571..3a991ccd5 100644
--- a/src/box/sql.c
+++ b/src/box/sql.c
@@ -54,6 +54,7 @@
#include "iproto_constants.h"
#include "fk_constraint.h"
#include "mpstream.h"
+#include "prep_stmt.h"
static sql *db = NULL;
@@ -74,6 +75,8 @@ sql_init()
if (sql_init_db(&db) != 0)
panic("failed to initialize SQL subsystem");
+ sql_prepared_stmt_cache_init();
+
assert(db != NULL);
}
diff --git a/test/app-tap/init_script.result b/test/app-tap/init_script.result
index 799297ba0..551a0bbeb 100644
--- a/test/app-tap/init_script.result
+++ b/test/app-tap/init_script.result
@@ -31,24 +31,25 @@ box.cfg
26 replication_sync_timeout:300
27 replication_timeout:1
28 slab_alloc_factor:1.05
-29 strip_core:true
-30 too_long_threshold:0.5
-31 vinyl_bloom_fpr:0.05
-32 vinyl_cache:134217728
-33 vinyl_dir:.
-34 vinyl_max_tuple_size:1048576
-35 vinyl_memory:134217728
-36 vinyl_page_size:8192
-37 vinyl_read_threads:1
-38 vinyl_run_count_per_level:2
-39 vinyl_run_size_ratio:3.5
-40 vinyl_timeout:60
-41 vinyl_write_threads:4
-42 wal_dir:.
-43 wal_dir_rescan_delay:2
-44 wal_max_size:268435456
-45 wal_mode:write
-46 worker_pool_threads:4
+29 sql_cache_size:5242880
+30 strip_core:true
+31 too_long_threshold:0.5
+32 vinyl_bloom_fpr:0.05
+33 vinyl_cache:134217728
+34 vinyl_dir:.
+35 vinyl_max_tuple_size:1048576
+36 vinyl_memory:134217728
+37 vinyl_page_size:8192
+38 vinyl_read_threads:1
+39 vinyl_run_count_per_level:2
+40 vinyl_run_size_ratio:3.5
+41 vinyl_timeout:60
+42 vinyl_write_threads:4
+43 wal_dir:.
+44 wal_dir_rescan_delay:2
+45 wal_max_size:268435456
+46 wal_mode:write
+47 worker_pool_threads:4
--
-- Test insert from detached fiber
--
diff --git a/test/box/admin.result b/test/box/admin.result
index 6126f3a97..852c1cde8 100644
--- a/test/box/admin.result
+++ b/test/box/admin.result
@@ -83,6 +83,8 @@ cfg_filter(box.cfg)
- 1
- - slab_alloc_factor
- 1.05
+ - - sql_cache_size
+ - 5242880
- - strip_core
- true
- - too_long_threshold
diff --git a/test/box/cfg.result b/test/box/cfg.result
index 5370bb870..9542e6375 100644
--- a/test/box/cfg.result
+++ b/test/box/cfg.result
@@ -71,6 +71,8 @@ cfg_filter(box.cfg)
| - 1
| - - slab_alloc_factor
| - 1.05
+ | - - sql_cache_size
+ | - 5242880
| - - strip_core
| - true
| - - too_long_threshold
@@ -170,6 +172,8 @@ cfg_filter(box.cfg)
| - 1
| - - slab_alloc_factor
| - 1.05
+ | - - sql_cache_size
+ | - 5242880
| - - strip_core
| - true
| - - too_long_threshold
@@ -315,6 +319,9 @@ box.cfg{memtx_memory = box.cfg.memtx_memory}
box.cfg{vinyl_memory = box.cfg.vinyl_memory}
| ---
| ...
+box.cfg{sql_cache_size = 1024}
+ | ---
+ | ...
--------------------------------------------------------------------------------
-- Test of default cfg options
diff --git a/test/box/cfg.test.lua b/test/box/cfg.test.lua
index 56ccb6767..e129568e6 100644
--- a/test/box/cfg.test.lua
+++ b/test/box/cfg.test.lua
@@ -51,6 +51,7 @@ box.cfg{replicaset_uuid = '12345678-0123-5678-1234-abcdefabcdef'}
box.cfg{memtx_memory = box.cfg.memtx_memory}
box.cfg{vinyl_memory = box.cfg.vinyl_memory}
+box.cfg{sql_cache_size = 1024}
--------------------------------------------------------------------------------
-- Test of default cfg options
diff --git a/test/box/misc.result b/test/box/misc.result
index b2930515b..78ffbf1dc 100644
--- a/test/box/misc.result
+++ b/test/box/misc.result
@@ -535,6 +535,7 @@ t;
203: box.error.BOOTSTRAP_READONLY
204: box.error.SQL_FUNC_WRONG_RET_COUNT
205: box.error.FUNC_INVALID_RETURN_TYPE
+ 206: box.error.SQL_PREPARE
...
test_run:cmd("setopt delimiter ''");
---
--
2.15.1
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