[tarantool-patches] Re: [PATCH v1 1/1] sql: fix perf degradation on name normalization

[Vladislav Shpilevoy <v.shpilevoy@tarantool.org>]

LGTM.

On 04/04/2019 21:08, Kirill Shcherbatov wrote:
>> 1. Missed diag_set.
>> 2. Again.
> Sorry, accidentally dropped it
> 
>> 3. That name was ok to be local for utf8.c, but now
>> it is global, and 'root_map' in the whole scope of
>> tarantool looks ambiguous. What it is? MessagePack map?
>> Lua table map? RB-tree map? What is 'root'? I propose
>>
>>     icu_ucase_default_map
> Songs good.
> 
> ==========================================
> Diff:
> ==========================================
> diff --git a/src/box/sql/util.c b/src/box/sql/util.c
> index 2f3c17c9a..52a86635c 100644
> --- a/src/box/sql/util.c
> +++ b/src/box/sql/util.c
> @@ -268,9 +268,9 @@ sql_normalize_name(char *dst, int dst_size, const char *src, int src_len)
>  		return src_len + 1;
>  	}
>  	UErrorCode status = U_ZERO_ERROR;
> -	assert(root_map != NULL);
> -	int len = ucasemap_utf8ToUpper(root_map, dst, dst_size, src,
> -				       src_len, &status);
> +	assert(icu_ucase_default_map != NULL);
> +	int len = ucasemap_utf8ToUpper(icu_ucase_default_map, dst, dst_size,
> +				       src, src_len, &status);
>  	assert(U_SUCCESS(status) || status == U_BUFFER_OVERFLOW_ERROR);
>  	return len + 1;
>  }
> @@ -310,7 +310,7 @@ sql_normalized_name_region_new(struct region *r, const char *name, int len)
>  	size_t region_svp = region_used(r);
>  	char *res = region_alloc(r, size);
>  	if (res == NULL)
> -		return NULL;
> +		goto oom_error;
>  	int rc = sql_normalize_name(res, size, name, len);
>  	if (rc <= size)
>  		return res;
> @@ -319,10 +319,14 @@ sql_normalized_name_region_new(struct region *r, const char *name, int len)
>  	region_truncate(r, region_svp);
>  	res = region_alloc(r, size);
>  	if (res == NULL)
> -		return NULL;
> +		goto oom_error;
>  	if (sql_normalize_name(res, size, name, len) > size)
>  		unreachable();
>  	return res;
> +
> +oom_error:
> +	diag_set(OutOfMemory, size, "region_alloc", "res");
> +	return NULL;
>  }
>  
>  /* Convenient short-hand */
> diff --git a/src/lib/coll/coll.c b/src/lib/coll/coll.c
> index 21f2489d4..495eb6d64 100644
> --- a/src/lib/coll/coll.c
> +++ b/src/lib/coll/coll.c
> @@ -37,7 +37,7 @@
>  #include <unicode/ucasemap.h>
>  #include <trivia/config.h>
>  
> -struct UCaseMap *root_map = NULL;
> +struct UCaseMap *icu_ucase_default_map = NULL;
>  
>  #define mh_name _coll
>  struct mh_coll_key_t {
> @@ -419,14 +419,14 @@ coll_init()
>  {
>  	UErrorCode err = U_ZERO_ERROR;
>  	coll_cache = mh_coll_new();
> -	root_map = ucasemap_open("", 0, &err);
> -	if (coll_cache == NULL || root_map == NULL)
> +	icu_ucase_default_map = ucasemap_open("", 0, &err);
> +	if (coll_cache == NULL || icu_ucase_default_map == NULL)
>  		panic("Can not create system collations cache");
>  }
>  
>  void
>  coll_free()
>  {
> -	ucasemap_close(root_map);
> +	ucasemap_close(icu_ucase_default_map);
>  	mh_coll_delete(coll_cache);
>  }
> diff --git a/src/lib/coll/coll.h b/src/lib/coll/coll.h
> index 713c9646e..1f5b29a2e 100644
> --- a/src/lib/coll/coll.h
> +++ b/src/lib/coll/coll.h
> @@ -54,7 +54,7 @@ typedef size_t (*coll_hint_f)(const char *s, size_t s_len, char *buf,
>  struct UCollator;
>  
>  /** Default universal casemap for case transformations. */
> -extern struct UCaseMap *root_map;
> +extern struct UCaseMap *icu_ucase_default_map;
>  
>  /**
>   * Collation. It has no unique features like name, id or owner.
> diff --git a/src/lua/utf8.c b/src/lua/utf8.c
> index 311698bda..d829b57b4 100644
> --- a/src/lua/utf8.c
> +++ b/src/lua/utf8.c
> @@ -61,11 +61,11 @@ utf8_str_to_case(struct lua_State *L, const char *src, int src_bsize,
>  		}
>  		int real_bsize;
>  		if (is_to_upper) {
> -			real_bsize = ucasemap_utf8ToUpper(root_map, dst,
> +			real_bsize = ucasemap_utf8ToUpper(icu_ucase_default_map, dst,
>  							  dst_bsize, src,
>  							  src_bsize, &err);
>  		} else {
> -			real_bsize = ucasemap_utf8ToLower(root_map, dst,
> +			real_bsize = ucasemap_utf8ToLower(icu_ucase_default_map, dst,
>  							  dst_bsize, src,
>  							  src_bsize, &err);
>  		}
> @@ -444,7 +444,7 @@ static const struct luaL_Reg utf8_lib[] = {
>  void
>  tarantool_lua_utf8_init(struct lua_State *L)
>  {
> -	assert(root_map != NULL);
> +	assert(icu_ucase_default_map != NULL);
>  	struct coll_def def;
>  	memset(&def, 0, sizeof(def));
>  	def.icu.strength = COLL_ICU_STRENGTH_TERTIARY;
> 
> ==========================================
> Patch:
> ==========================================
> From a779238e296a78830c68bdee305bb305336c5a34 Mon Sep 17 00:00:00 2001
> Message-Id: <a779238e296a78830c68bdee305bb305336c5a34.1554401202.git.kshcherbatov@tarantool.org>
> From: Kirill Shcherbatov <kshcherbatov@tarantool.org>
> Date: Thu, 4 Apr 2019 15:53:02 +0300
> Subject: [PATCH v1 1/1] sql: fix perf degradation on name normalization
> 
> Because sql_normalize_name used to be called twice - to estimate
> the size of the name buffer and to process data querying the
> UCaseMap object each time performance in SQL felt by 15%.
> 
> This patch should eliminate some of the negative effects of using
> ICU for name normalization.
> 
> Thanks @avtikhon for a bechmark
> 
> Follow up e7558062d3559e6bcc18f91eacb88269428321dc
> ---
>  src/box/sql/expr.c       | 29 +++++++--------
>  src/box/sql/parse.y      | 21 +++++------
>  src/box/sql/sqlInt.h     |  9 ++---
>  src/box/sql/trigger.c    | 22 +++++++-----
>  src/box/sql/util.c       | 77 ++++++++++++++++++++++------------------
>  src/lib/coll/coll.c      |  8 ++++-
>  src/lib/coll/coll.h      |  3 ++
>  src/lua/utf8.c           | 15 ++------
>  test/sql/errinj.result   |  9 ++++-
>  test/sql/errinj.test.lua |  2 ++
>  10 files changed, 105 insertions(+), 90 deletions(-)
> 
> diff --git a/src/box/sql/expr.c b/src/box/sql/expr.c
> index 4b98bd175..0d61be344 100644
> --- a/src/box/sql/expr.c
> +++ b/src/box/sql/expr.c
> @@ -965,22 +965,13 @@ sql_expr_new(struct sql *db, int op, const struct Token *token)
>  struct Expr *
>  sql_expr_new_dequoted(struct sql *db, int op, const struct Token *token)
>  {
> -	int extra_size = 0;
> -	bool is_name = false;
> +	int extra_size = 0, rc;
>  	if (token != NULL) {
>  		int val;
>  		assert(token->z != NULL || token->n == 0);
>  		if (sql_expr_token_to_int(op, token, &val) == 0)
>  			return sql_expr_new_int(db, val);
> -		is_name = op == TK_ID || op == TK_COLLATE || op == TK_FUNCTION;
> -		if (is_name) {
> -			extra_size = sql_normalize_name(NULL, 0, token->z,
> -							token->n);
> -			if (extra_size < 0)
> -				return NULL;
> -		} else {
> -			extra_size = token->n + 1;
> -		}
> +		extra_size = token->n + 1;
>  	}
>  	struct Expr *e = sql_expr_new_empty(db, op, extra_size);
>  	if (e == NULL || token == NULL || token->n == 0)
> @@ -988,14 +979,20 @@ sql_expr_new_dequoted(struct sql *db, int op, const struct Token *token)
>  	e->u.zToken = (char *) &e[1];
>  	if (token->z[0] == '"')
>  		e->flags |= EP_DblQuoted;
> -	if (! is_name) {
> +	if (op != TK_ID && op != TK_COLLATE && op != TK_FUNCTION) {
>  		memcpy(e->u.zToken, token->z, token->n);
>  		e->u.zToken[token->n] = '\0';
>  		sqlDequote(e->u.zToken);
> -	} else if (sql_normalize_name(e->u.zToken, extra_size, token->z,
> -				      token->n) < 0) {
> -		sql_expr_delete(db, e, false);
> -		return NULL;
> +	} else if ((rc = sql_normalize_name(e->u.zToken, extra_size, token->z,
> +					    token->n)) > extra_size) {
> +		extra_size = rc;
> +		e = sqlDbReallocOrFree(db, e, sizeof(*e) + extra_size);
> +		if (e == NULL)
> +			return NULL;
> +		e->u.zToken = (char *) &e[1];
> +		if (sql_normalize_name(e->u.zToken, extra_size, token->z,
> +				       token->n) > extra_size)
> +			unreachable();
>  	}
>  	return e;
>  }
> diff --git a/src/box/sql/parse.y b/src/box/sql/parse.y
> index ed5c05436..4581ef6e7 100644
> --- a/src/box/sql/parse.y
> +++ b/src/box/sql/parse.y
> @@ -893,15 +893,8 @@ idlist(A) ::= nm(Y). {
>    ** that created the expression.
>    */
>    static void spanExpr(ExprSpan *pOut, Parse *pParse, int op, Token t){
> -    int name_sz = 0;
>      struct Expr *p = NULL;
> -    if (op != TK_VARIABLE) {
> -      name_sz = sql_normalize_name(NULL, 0, t.z, t.n);
> -      if (name_sz < 0)
> -        goto tarantool_error;
> -    } else {
> -      name_sz = t.n + 1;
> -    }
> +    int name_sz = t.n + 1;
>      p = sqlDbMallocRawNN(pParse->db, sizeof(Expr) + name_sz);
>      if( p ){
>        memset(p, 0, sizeof(Expr));
> @@ -936,8 +929,16 @@ idlist(A) ::= nm(Y). {
>        p->iAgg = -1;
>        p->u.zToken = (char*)&p[1];
>        if (op != TK_VARIABLE) {
> -        if (sql_normalize_name(p->u.zToken, name_sz, t.z, t.n) < 0)
> -          goto tarantool_error;
> +        int rc = sql_normalize_name(p->u.zToken, name_sz, t.z, t.n);
> +        if (rc > name_sz) {
> +          name_sz = rc;
> +          p = sqlDbReallocOrFree(pParse->db, p, sizeof(*p) + name_sz);
> +          if (p == NULL)
> +            goto tarantool_error;
> +          p->u.zToken = (char *) &p[1];
> +          if (sql_normalize_name(p->u.zToken, name_sz, t.z, t.n) > name_sz)
> +              unreachable();
> +        }
>        } else {
>          memcpy(p->u.zToken, t.z, t.n);
>          p->u.zToken[t.n] = 0;
> diff --git a/src/box/sql/sqlInt.h b/src/box/sql/sqlInt.h
> index d8dc03284..b322602dc 100644
> --- a/src/box/sql/sqlInt.h
> +++ b/src/box/sql/sqlInt.h
> @@ -3175,15 +3175,10 @@ void sqlDequote(char *);
>   * @param dst A buffer for the result string. The result will be
>   *        0-terminated if the buffer is large enough. The contents
>   *        is undefined in case of failure.
> - * @param dst_size The size of the buffer (number of bytes). If it
> - *        is 0, then dest may be NULL and the function will only
> - *        return the length of the result without writing any of
> - *        the result string
> + * @param dst_size The size of the buffer (number of bytes).
>   * @param src The original string.
>   * @param src_len The length of the original string.
> - * @retval The count of bytes written(or need to be written) on
> - *         success.
> - * @retval < 0 Otherwise. The diag message is set.
> + * @retval The count of bytes written (or need to be written).
>   */
>  int
>  sql_normalize_name(char *dst, int dst_size, const char *src, int src_len);
> diff --git a/src/box/sql/trigger.c b/src/box/sql/trigger.c
> index 20b2c970c..14e4198a8 100644
> --- a/src/box/sql/trigger.c
> +++ b/src/box/sql/trigger.c
> @@ -278,10 +278,7 @@ sql_trigger_select_step(struct sql *db, struct Select *select)
>  static struct TriggerStep *
>  sql_trigger_step_new(struct sql *db, u8 op, struct Token *target_name)
>  {
> -	int name_size =
> -		sql_normalize_name(NULL, 0, target_name->z, target_name->n);
> -	if (name_size < 0)
> -		return NULL;
> +	int name_size = target_name->n + 1;
>  	int size = sizeof(struct TriggerStep) + name_size;
>  	struct TriggerStep *trigger_step = sqlDbMallocZero(db, size);
>  	if (trigger_step == NULL) {
> @@ -289,10 +286,19 @@ sql_trigger_step_new(struct sql *db, u8 op, struct Token *target_name)
>  		return NULL;
>  	}
>  	char *z = (char *)&trigger_step[1];
> -	if (sql_normalize_name(z, name_size, target_name->z,
> -			       target_name->n) < 0) {
> -		sqlDbFree(db, trigger_step);
> -		return NULL;
> +	int rc = sql_normalize_name(z, name_size, target_name->z,
> +				    target_name->n);
> +	if (rc > name_size) {
> +		name_size = rc;
> +		trigger_step = sqlDbReallocOrFree(db, trigger_step,
> +						  sizeof(*trigger_step) +
> +						  name_size);
> +		if (trigger_step == NULL)
> +			return NULL;
> +		z = (char *) &trigger_step[1];
> +		if (sql_normalize_name(z, name_size, target_name->z,
> +				       target_name->n) > name_size)
> +			unreachable();
>  	}
>  	trigger_step->zTarget = z;
>  	trigger_step->op = op;
> diff --git a/src/box/sql/util.c b/src/box/sql/util.c
> index a13efa682..52a86635c 100644
> --- a/src/box/sql/util.c
> +++ b/src/box/sql/util.c
> @@ -41,6 +41,7 @@
>  #if HAVE_ISNAN || SQL_HAVE_ISNAN
>  #include <math.h>
>  #endif
> +#include "coll/coll.h"
>  #include <unicode/ucasemap.h>
>  #include "errinj.h"
>  
> @@ -259,67 +260,73 @@ int
>  sql_normalize_name(char *dst, int dst_size, const char *src, int src_len)
>  {
>  	assert(src != NULL);
> +	assert(dst != NULL && dst_size > 0);
>  	if (sqlIsquote(src[0])){
> -		if (dst_size == 0)
> -			return src_len + 1;
>  		memcpy(dst, src, src_len);
>  		dst[src_len] = '\0';
>  		sqlDequote(dst);
>  		return src_len + 1;
>  	}
>  	UErrorCode status = U_ZERO_ERROR;
> -	ERROR_INJECT(ERRINJ_SQL_NAME_NORMALIZATION, {
> -		status = U_MEMORY_ALLOCATION_ERROR;
> -		goto error;
> -	});
> -	UCaseMap *case_map = ucasemap_open(NULL, 0, &status);
> -	if (case_map == NULL)
> -		goto error;
> -	int len = ucasemap_utf8ToUpper(case_map, dst, dst_size, src, src_len,
> -				       &status);
> -	ucasemap_close(case_map);
> -	assert(U_SUCCESS(status) ||
> -	       (dst_size == 0 && status == U_BUFFER_OVERFLOW_ERROR));
> +	assert(icu_ucase_default_map != NULL);
> +	int len = ucasemap_utf8ToUpper(icu_ucase_default_map, dst, dst_size,
> +				       src, src_len, &status);
> +	assert(U_SUCCESS(status) || status == U_BUFFER_OVERFLOW_ERROR);
>  	return len + 1;
> -error:
> -	diag_set(CollationError,
> -		 "string conversion to the uppercase failed: %s",
> -		 u_errorName(status));
> -	return -1;
>  }
>  
>  char *
>  sql_normalized_name_db_new(struct sql *db, const char *name, int len)
>  {
> -	int size = sql_normalize_name(NULL, 0, name, len);
> -	if (size < 0)
> +	int size = len + 1;
> +	ERROR_INJECT(ERRINJ_SQL_NAME_NORMALIZATION, {
> +		diag_set(OutOfMemory, size, "sqlDbMallocRawNN", "res");
>  		return NULL;
> +	});
>  	char *res = sqlDbMallocRawNN(db, size);
> -	if (res == NULL) {
> -		diag_set(OutOfMemory, size, "sqlDbMallocRawNN", "res");
> +	if (res == NULL)
>  		return NULL;
> -	}
> -	if (sql_normalize_name(res, size, name, len) < 0) {
> -		sqlDbFree(db, res);
> +	int rc = sql_normalize_name(res, size, name, len);
> +	if (rc <= size)
> +		return res;
> +
> +	size = rc;
> +	res = sqlDbReallocOrFree(db, res, size);
> +	if (res == NULL)
>  		return NULL;
> -	}
> +	if (sql_normalize_name(res, size, name, len) > size)
> +		unreachable();
>  	return res;
>  }
>  
>  char *
>  sql_normalized_name_region_new(struct region *r, const char *name, int len)
>  {
> -	int size = sql_normalize_name(NULL, 0, name, len);
> -	if (size < 0)
> -		return NULL;
> -	char *res = (char *) region_alloc(r, size);
> -	if (res == NULL) {
> +	int size = len + 1;
> +	ERROR_INJECT(ERRINJ_SQL_NAME_NORMALIZATION, {
>  		diag_set(OutOfMemory, size, "region_alloc", "res");
>  		return NULL;
> -	}
> -	if (sql_normalize_name(res, size, name, len) < 0)
> -		return NULL;
> +	});
> +	size_t region_svp = region_used(r);
> +	char *res = region_alloc(r, size);
> +	if (res == NULL)
> +		goto oom_error;
> +	int rc = sql_normalize_name(res, size, name, len);
> +	if (rc <= size)
> +		return res;
> +
> +	size = rc;
> +	region_truncate(r, region_svp);
> +	res = region_alloc(r, size);
> +	if (res == NULL)
> +		goto oom_error;
> +	if (sql_normalize_name(res, size, name, len) > size)
> +		unreachable();
>  	return res;
> +
> +oom_error:
> +	diag_set(OutOfMemory, size, "region_alloc", "res");
> +	return NULL;
>  }
>  
>  /* Convenient short-hand */
> diff --git a/src/lib/coll/coll.c b/src/lib/coll/coll.c
> index b83f0fdc7..495eb6d64 100644
> --- a/src/lib/coll/coll.c
> +++ b/src/lib/coll/coll.c
> @@ -34,8 +34,11 @@
>  #include "diag.h"
>  #include "assoc.h"
>  #include <unicode/ucol.h>
> +#include <unicode/ucasemap.h>
>  #include <trivia/config.h>
>  
> +struct UCaseMap *icu_ucase_default_map = NULL;
> +
>  #define mh_name _coll
>  struct mh_coll_key_t {
>  	const char *str;
> @@ -414,13 +417,16 @@ coll_unref(struct coll *coll)
>  void
>  coll_init()
>  {
> +	UErrorCode err = U_ZERO_ERROR;
>  	coll_cache = mh_coll_new();
> -	if (coll_cache == NULL)
> +	icu_ucase_default_map = ucasemap_open("", 0, &err);
> +	if (coll_cache == NULL || icu_ucase_default_map == NULL)
>  		panic("Can not create system collations cache");
>  }
>  
>  void
>  coll_free()
>  {
> +	ucasemap_close(icu_ucase_default_map);
>  	mh_coll_delete(coll_cache);
>  }
> diff --git a/src/lib/coll/coll.h b/src/lib/coll/coll.h
> index c505804f6..1f5b29a2e 100644
> --- a/src/lib/coll/coll.h
> +++ b/src/lib/coll/coll.h
> @@ -53,6 +53,9 @@ typedef size_t (*coll_hint_f)(const char *s, size_t s_len, char *buf,
>  
>  struct UCollator;
>  
> +/** Default universal casemap for case transformations. */
> +extern struct UCaseMap *icu_ucase_default_map;
> +
>  /**
>   * Collation. It has no unique features like name, id or owner.
>   * Only functional part - comparator, locale, ICU settings.
> diff --git a/src/lua/utf8.c b/src/lua/utf8.c
> index de026a921..d829b57b4 100644
> --- a/src/lua/utf8.c
> +++ b/src/lua/utf8.c
> @@ -38,9 +38,6 @@
>  
>  extern struct ibuf *tarantool_lua_ibuf;
>  
> -/** Default universal casemap for case transformations. */
> -static UCaseMap *root_map = NULL;
> -
>  /** Collations for cmp/casecmp functions. */
>  static struct coll *unicode_coll = NULL;
>  static struct coll *unicode_ci_coll = NULL;
> @@ -64,11 +61,11 @@ utf8_str_to_case(struct lua_State *L, const char *src, int src_bsize,
>  		}
>  		int real_bsize;
>  		if (is_to_upper) {
> -			real_bsize = ucasemap_utf8ToUpper(root_map, dst,
> +			real_bsize = ucasemap_utf8ToUpper(icu_ucase_default_map, dst,
>  							  dst_bsize, src,
>  							  src_bsize, &err);
>  		} else {
> -			real_bsize = ucasemap_utf8ToLower(root_map, dst,
> +			real_bsize = ucasemap_utf8ToLower(icu_ucase_default_map, dst,
>  							  dst_bsize, src,
>  							  src_bsize, &err);
>  		}
> @@ -447,12 +444,7 @@ static const struct luaL_Reg utf8_lib[] = {
>  void
>  tarantool_lua_utf8_init(struct lua_State *L)
>  {
> -	UErrorCode err = U_ZERO_ERROR;
> -	root_map = ucasemap_open("", 0, &err);
> -	if (root_map == NULL) {
> -		luaL_error(L, tt_sprintf("error in ICU ucasemap_open: %s",
> -					 u_errorName(err)));
> -	}
> +	assert(icu_ucase_default_map != NULL);
>  	struct coll_def def;
>  	memset(&def, 0, sizeof(def));
>  	def.icu.strength = COLL_ICU_STRENGTH_TERTIARY;
> @@ -474,7 +466,6 @@ error_coll:
>  void
>  tarantool_lua_utf8_free()
>  {
> -	ucasemap_close(root_map);
>  	if (unicode_coll != NULL)
>  		coll_unref(unicode_coll);
>  	if (unicode_ci_coll != NULL)
> diff --git a/test/sql/errinj.result b/test/sql/errinj.result
> index dead00f7d..5a427e855 100644
> --- a/test/sql/errinj.result
> +++ b/test/sql/errinj.result
> @@ -450,7 +450,14 @@ errinj.set("ERRINJ_SQL_NAME_NORMALIZATION", true)
>  ...
>  box.execute("CREATE TABLE hello (id INT primary key,x INT,y INT);")
>  ---
> -- error: 'string conversion to the uppercase failed: U_MEMORY_ALLOCATION_ERROR'
> +- error: Failed to allocate 6 bytes in sqlDbMallocRawNN for res
> +...
> +dummy_f = function(int) return 1 end
> +---
> +...
> +box.internal.sql_create_function("counter1", "INT", dummy_f, -1, false)
> +---
> +- error: Failed to allocate 9 bytes in region_alloc for res
>  ...
>  errinj.set("ERRINJ_SQL_NAME_NORMALIZATION", false)
>  ---
> diff --git a/test/sql/errinj.test.lua b/test/sql/errinj.test.lua
> index 736e66957..7f4b30baf 100644
> --- a/test/sql/errinj.test.lua
> +++ b/test/sql/errinj.test.lua
> @@ -146,4 +146,6 @@ errinj.set("ERRINJ_WAL_DELAY", false)
>  errinj = box.error.injection
>  errinj.set("ERRINJ_SQL_NAME_NORMALIZATION", true)
>  box.execute("CREATE TABLE hello (id INT primary key,x INT,y INT);")
> +dummy_f = function(int) return 1 end
> +box.internal.sql_create_function("counter1", "INT", dummy_f, -1, false)
>  errinj.set("ERRINJ_SQL_NAME_NORMALIZATION", false)
> -- 
> 2.21.0
>