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Commit7e137f8

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Extend pgbench's expression syntax to support a few built-in functions.
Fabien Coelho, reviewed mostly by Michael Paquier and me, but also byHeikki Linnakangas, BeomYong Lee, Kyotaro Horiguchi, OleksanderShulgin, and Álvaro Herrera.
1 parentbd6cf3f commit7e137f8

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5 files changed

+409
-97
lines changed

5 files changed

+409
-97
lines changed

‎doc/src/sgml/ref/pgbench.sgml‎

Lines changed: 61 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -786,7 +786,7 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
786786
</para>
787787

788788
<variablelist>
789-
<varlistentry>
789+
<varlistentry id='pgbench-metacommand-set'>
790790
<term>
791791
<literal>\set <replaceable>varname</> <replaceable>expression</></literal>
792792
</term>
@@ -798,8 +798,10 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
798798
The expression may contain integer constants such as <literal>5432</>,
799799
references to variables <literal>:</><replaceable>variablename</>,
800800
and expressions composed of unary (<literal>-</>) or binary operators
801-
(<literal>+</>, <literal>-</>, <literal>*</>, <literal>/</>, <literal>%</>)
802-
with their usual associativity, and parentheses.
801+
(<literal>+</>, <literal>-</>, <literal>*</>, <literal>/</>,
802+
<literal>%</>) with their usual associativity,
803+
<link linkend="pgbench-builtin-functions">function calls</>, and
804+
parentheses.
803805
</para>
804806

805807
<para>
@@ -994,6 +996,62 @@ END;
994996

995997
</refsect2>
996998

999+
<refsect2 id="pgbench-builtin-functions">
1000+
<title>Built-In Functions</title>
1001+
1002+
<para>
1003+
The following functions are built into <application>pgbench</> and
1004+
may be used in conjunction with
1005+
<link linkend="pgbench-metacommand-set"><literal>\set</literal></link>.
1006+
</para>
1007+
1008+
<!-- list pgbench functions in alphabetical order -->
1009+
<table>
1010+
<title>pgbench Functions</title>
1011+
<tgroup cols="5">
1012+
<thead>
1013+
<row>
1014+
<entry>Function</entry>
1015+
<entry>Return Type</entry>
1016+
<entry>Description</entry>
1017+
<entry>Example</entry>
1018+
<entry>Result</entry>
1019+
</row>
1020+
</thead>
1021+
<tbody>
1022+
<row>
1023+
<entry><literal><function>abs(<replaceable>a</>)</></></>
1024+
<entry>same as <replaceable>a</></>
1025+
<entry>integer value</>
1026+
<entry><literal>abs(-17)</></>
1027+
<entry><literal>17</></>
1028+
</row>
1029+
<row>
1030+
<entry><literal><function>debug(<replaceable>a</>)</></></>
1031+
<entry>same as <replaceable>a</> </>
1032+
<entry>print to <systemitem>stderr</systemitem> the given argument</>
1033+
<entry><literal>debug(5432)</></>
1034+
<entry><literal>5432</></>
1035+
</row>
1036+
<row>
1037+
<entry><literal><function>max(<replaceable>i</> [, <replaceable>...</> ] )</></></>
1038+
<entry>integer</>
1039+
<entry>maximum value</>
1040+
<entry><literal>max(5, 4, 3, 2)</></>
1041+
<entry><literal>5</></>
1042+
</row>
1043+
<row>
1044+
<entry><literal><function>min(<replaceable>i</> [, <replaceable>...</> ] )</></></>
1045+
<entry>integer</>
1046+
<entry>minimum value</>
1047+
<entry><literal>min(5, 4, 3, 2)</></>
1048+
<entry><literal>2</></>
1049+
</row>
1050+
</tbody>
1051+
</tgroup>
1052+
</table>
1053+
</refsect2>
1054+
9971055
<refsect2>
9981056
<title>Per-Transaction Logging</title>
9991057

‎src/bin/pgbench/exprparse.y‎

Lines changed: 146 additions & 15 deletions
Original file line numberDiff line numberDiff line change
@@ -16,10 +16,13 @@
1616

1717
PgBenchExpr *expr_parse_result;
1818

19+
static PgBenchExprList *make_elist(PgBenchExpr *exp, PgBenchExprList *list);
1920
static PgBenchExpr *make_integer_constant(int64 ival);
2021
static PgBenchExpr *make_variable(char *varname);
21-
static PgBenchExpr *make_op(charoperator, PgBenchExpr *lexpr,
22+
static PgBenchExpr *make_op(constchar*operator, PgBenchExpr *lexpr,
2223
PgBenchExpr *rexpr);
24+
staticintfind_func(constchar *fname);
25+
static PgBenchExpr *make_func(constint fnumber, PgBenchExprList *args);
2326

2427
%}
2528

@@ -31,13 +34,15 @@ static PgBenchExpr *make_op(char operator, PgBenchExpr *lexpr,
3134
int64ival;
3235
char *str;
3336
PgBenchExpr *expr;
37+
PgBenchExprList *elist;
3438
}
3539

40+
%type<elist>elist
3641
%type<expr>expr
37-
%type<ival>INTEGER
38-
%type<str>VARIABLE
42+
%type<ival>INTEGERfunction
43+
%type<str>VARIABLEFUNCTION
3944

40-
%tokenINTEGERVARIABLE
45+
%tokenINTEGERVARIABLEFUNCTION
4146
%tokenCHAR_ERROR/* never used, will raise a syntax error*/
4247

4348
/* Precedence: lowest to highest*/
@@ -49,16 +54,25 @@ static PgBenchExpr *make_op(char operator, PgBenchExpr *lexpr,
4954

5055
result:expr{ expr_parse_result =$1; }
5156

57+
elist: {$$ =NULL; }
58+
|expr {$$ = make_elist($1,NULL); }
59+
|elist','expr{$$ = make_elist($3,$1); }
60+
;
61+
5262
expr:'('expr')'{$$ =$2; }
5363
|'+'expr %precUMINUS{$$ =$2; }
54-
|'-'expr %precUMINUS{$$ = make_op('-', make_integer_constant(0),$2); }
55-
|expr'+'expr{$$ = make_op('+',$1,$3); }
56-
|expr'-'expr{$$ = make_op('-',$1,$3); }
57-
|expr'*'expr{$$ = make_op('*',$1,$3); }
58-
|expr'/'expr{$$ = make_op('/',$1,$3); }
59-
|expr'%'expr{$$ = make_op('%',$1,$3); }
64+
|'-'expr %precUMINUS{$$ = make_op("-", make_integer_constant(0),$2); }
65+
|expr'+'expr{$$ = make_op("+",$1,$3); }
66+
|expr'-'expr{$$ = make_op("-",$1,$3); }
67+
|expr'*'expr{$$ = make_op("*",$1,$3); }
68+
|expr'/'expr{$$ = make_op("/",$1,$3); }
69+
|expr'%'expr{$$ = make_op("%",$1,$3); }
6070
|INTEGER{$$ = make_integer_constant($1); }
6171
|VARIABLE {$$ = make_variable($1); }
72+
|function'('elist')'{$$ = make_func($1,$3); }
73+
;
74+
75+
function:FUNCTION{$$ = find_func($1); pg_free($1); }
6276
;
6377

6478
%%
@@ -84,14 +98,131 @@ make_variable(char *varname)
8498
}
8599

86100
static PgBenchExpr *
87-
make_op(charoperator, PgBenchExpr *lexpr, PgBenchExpr *rexpr)
101+
make_op(constchar *operator, PgBenchExpr *lexpr, PgBenchExpr *rexpr)
102+
{
103+
returnmake_func(find_func(operator),
104+
make_elist(rexpr,make_elist(lexpr,NULL)));
105+
}
106+
107+
/*
108+
* List of available functions:
109+
* - fname: function name
110+
* - nargs: number of arguments
111+
* -1 is a special value for min & max meaning #args >= 1
112+
* - tag: function identifier from PgBenchFunction enum
113+
*/
114+
staticstruct
115+
{
116+
char * fname;
117+
int nargs;
118+
PgBenchFunction tag;
119+
} PGBENCH_FUNCTIONS[] = {
120+
/* parsed as operators, executed as functions*/
121+
{"+",2, PGBENCH_ADD },
122+
{"-",2, PGBENCH_SUB },
123+
{"*",2, PGBENCH_MUL },
124+
{"/",2, PGBENCH_DIV },
125+
{"%",2, PGBENCH_MOD },
126+
/* actual functions*/
127+
{"abs",1, PGBENCH_ABS },
128+
{"min", -1, PGBENCH_MIN },
129+
{"max", -1, PGBENCH_MAX },
130+
{"debug",1, PGBENCH_DEBUG },
131+
/* keep as last array element*/
132+
{NULL,0,0 }
133+
};
134+
135+
/*
136+
* Find a function from its name
137+
*
138+
* return the index of the function from the PGBENCH_FUNCTIONS array
139+
* or fail if the function is unknown.
140+
*/
141+
staticint
142+
find_func(constchar * fname)
143+
{
144+
int i =0;
145+
146+
while (PGBENCH_FUNCTIONS[i].fname)
147+
{
148+
if (pg_strcasecmp(fname, PGBENCH_FUNCTIONS[i].fname) ==0)
149+
return i;
150+
i++;
151+
}
152+
153+
expr_yyerror_more("unexpected function name", fname);
154+
155+
/* not reached*/
156+
return -1;
157+
}
158+
159+
/* Expression linked list builder*/
160+
static PgBenchExprList *
161+
make_elist(PgBenchExpr *expr, PgBenchExprList *list)
162+
{
163+
PgBenchExprLink * cons;
164+
165+
if (list ==NULL)
166+
{
167+
list =pg_malloc(sizeof(PgBenchExprList));
168+
list->head =NULL;
169+
list->tail =NULL;
170+
}
171+
172+
cons =pg_malloc(sizeof(PgBenchExprLink));
173+
cons->expr = expr;
174+
cons->next =NULL;
175+
176+
if (list->head ==NULL)
177+
list->head = cons;
178+
else
179+
list->tail->next = cons;
180+
181+
list->tail = cons;
182+
183+
return list;
184+
}
185+
186+
/* Return the length of an expression list*/
187+
staticint
188+
elist_length(PgBenchExprList *list)
189+
{
190+
PgBenchExprLink *link = list !=NULL? list->head:NULL;
191+
int len =0;
192+
193+
for (; link !=NULL; link = link->next)
194+
len++;
195+
196+
return len;
197+
}
198+
199+
/* Build function call expression*/
200+
static PgBenchExpr *
201+
make_func(constint fnumber, PgBenchExprList *args)
88202
{
89203
PgBenchExpr *expr =pg_malloc(sizeof(PgBenchExpr));
90204

91-
expr->etype = ENODE_OPERATOR;
92-
expr->u.operator.operator =operator;
93-
expr->u.operator.lexpr = lexpr;
94-
expr->u.operator.rexpr = rexpr;
205+
Assert(fnumber >=0);
206+
207+
if (PGBENCH_FUNCTIONS[fnumber].nargs >=0 &&
208+
PGBENCH_FUNCTIONS[fnumber].nargs !=elist_length(args))
209+
expr_yyerror_more("unexpected number of arguments",
210+
PGBENCH_FUNCTIONS[fnumber].fname);
211+
212+
/* check at least one arg for min & max*/
213+
if (PGBENCH_FUNCTIONS[fnumber].nargs == -1 &&
214+
elist_length(args) ==0)
215+
expr_yyerror_more("at least one argument expected",
216+
PGBENCH_FUNCTIONS[fnumber].fname);
217+
218+
expr->etype = ENODE_FUNCTION;
219+
expr->u.function.function = PGBENCH_FUNCTIONS[fnumber].tag;
220+
221+
/* only the link is used, the head/tail is not useful anymore*/
222+
expr->u.function.args = args !=NULL? args->head:NULL;
223+
if (args)
224+
pg_free(args);
225+
95226
return expr;
96227
}
97228

‎src/bin/pgbench/exprscan.l‎

Lines changed: 18 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -46,6 +46,7 @@ space[ \t\r\f]
4646
"%"{ yycol += yyleng;return'%'; }
4747
"("{ yycol += yyleng;return'('; }
4848
")"{ yycol += yyleng;return')'; }
49+
","{ yycol += yyleng;return','; }
4950

5051
:[a-zA-Z0-9_]+{
5152
yycol += yyleng;
@@ -57,8 +58,14 @@ space[ \t\r\f]
5758
yylval.ival =strtoint64(yytext);
5859
return INTEGER;
5960
}
61+
[a-zA-Z0-9_]+ {
62+
yycol += yyleng;
63+
yylval.str =pg_strdup(yytext);
64+
return FUNCTION;
65+
}
6066

6167
[\n]{ yycol =0; yyline++; }
68+
6269
{space}+{ yycol += yyleng;/* ignore */ }
6370

6471
.{
@@ -71,10 +78,16 @@ space[ \t\r\f]
7178
%%
7279

7380
void
74-
yyerror(constchar *message)
81+
expr_yyerror_more(constchar *message,constchar *more)
7582
{
7683
syntax_error(expr_source, expr_lineno, expr_full_line, expr_command,
77-
message,NULL, expr_col + yycol);
84+
message, more, expr_col + yycol);
85+
}
86+
87+
void
88+
yyerror(constchar *message)
89+
{
90+
expr_yyerror_more(message,NULL);
7891
}
7992

8093
/*
@@ -94,6 +107,9 @@ expr_scanner_init(const char *str, const char *source,
94107
expr_command = (char *) cmd;
95108
expr_col = (int) ecol;
96109

110+
/* reset column count for this scan */
111+
yycol =0;
112+
97113
/*
98114
* Might be left over after error
99115
*/

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