Hello Robert,
However, for obvious reasons the committer opinion prevails:-)
You're welcome to solicit other opinions. I'm not unwilling to give
way if there's a chorus of support for the way you've done it.
Hmmm. I do not expect much chorus on such a minor subject:-)
But to me it sounds like you're saying that it doesn't really matter
whether the system is scalable and maintainable because we only have 5
functions right now, which is a design philosophy with which I just
don't agree.
The design does not aim at scalability but at simplicity, otherwise I
would have done things quite differently: with many functions the "switch"
based selection does not scale anyway.
Anyway, attached are two patches, one for each approach.
The array (second patch) is not too bad if one agrees with a maximum
number of arguments, and also as I did not change the list structure
coming from the parser, so it does not need to manage the number of
arguments in the function structure. The code for min/max is also simpler
when dealing with an array instead of a linked list. I do not like much
array references in the code, so I tried to avoid them by using lval/rval
scalars for operator operands.
Please choose the one you prefer, and I'll adapt the remaining stuff to
your choice.
--
Fabien.
diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index ade1b53..f39f341 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -786,7 +786,7 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
</para>
<variablelist>
- <varlistentry>
+ <varlistentry id='pgbench-metacommand-set'>
<term>
<literal>\set <replaceable>varname</> <replaceable>expression</></literal>
</term>
@@ -798,8 +798,10 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
The expression may contain integer constants such as <literal>5432</>,
references to variables <literal>:</><replaceable>variablename</>,
and expressions composed of unary (<literal>-</>) or binary operators
- (<literal>+</>, <literal>-</>, <literal>*</>, <literal>/</>, <literal>%</>)
- with their usual associativity, and parentheses.
+ (<literal>+</>, <literal>-</>, <literal>*</>, <literal>/</>,
+ <literal>%</>) with their usual associativity,
+ <link linkend="pgbench-builtin-functions">function calls</>, and
+ parentheses.
</para>
<para>
@@ -994,6 +996,62 @@ END;
</refsect2>
+ <refsect2 id="pgbench-builtin-functions">
+ <title>Built-In Functions</title>
+
+ <para>
+ The following functions are built into <application>pgbench</> and
+ may be used in conjunction with
+ <link linkend="pgbench-metacommand-set"><literal>\set</literal></link>.
+ </para>
+
+ <!-- list pgbench functions in alphabetical order -->
+ <table>
+ <title>pgbench Functions</title>
+ <tgroup cols="5">
+ <thead>
+ <row>
+ <entry>Function</entry>
+ <entry>Return Type</entry>
+ <entry>Description</entry>
+ <entry>Example</entry>
+ <entry>Result</entry>
+ </row>
+ </thead>
+ <tbody>
+ <row>
+ <entry><literal><function>abs(<replaceable>a</>)</></></>
+ <entry>same as <replaceable>a</></>
+ <entry>integer value</>
+ <entry><literal>abs(-17)</></>
+ <entry><literal>17</></>
+ </row>
+ <row>
+ <entry><literal><function>debug(<replaceable>a</>)</></></>
+ <entry>same as <replaceable>a</> </>
+ <entry>print to <systemitem>stderr</systemitem> the given argument</>
+ <entry><literal>debug(5432)</></>
+ <entry><literal>5432</></>
+ </row>
+ <row>
+ <entry><literal><function>max(<replaceable>i</> [, <replaceable>...</> ] )</></></>
+ <entry>integer</>
+ <entry>maximum value</>
+ <entry><literal>max(5, 4, 3, 2)</></>
+ <entry><literal>5</></>
+ </row>
+ <row>
+ <entry><literal><function>min(<replaceable>i</> [, <replaceable>...</> ] )</></></>
+ <entry>integer</>
+ <entry>minimum value</>
+ <entry><literal>min(5, 4, 3, 2)</></>
+ <entry><literal>2</></>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+ </refsect2>
+
<refsect2>
<title>Per-Transaction Logging</title>
diff --git a/src/bin/pgbench/exprparse.y b/src/bin/pgbench/exprparse.y
index 06ee04b..cac4d5e 100644
--- a/src/bin/pgbench/exprparse.y
+++ b/src/bin/pgbench/exprparse.y
@@ -16,10 +16,13 @@
PgBenchExpr *expr_parse_result;
+static PgBenchExprList *make_elist(PgBenchExpr *exp, PgBenchExprList *list);
static PgBenchExpr *make_integer_constant(int64 ival);
static PgBenchExpr *make_variable(char *varname);
-static PgBenchExpr *make_op(char operator, PgBenchExpr *lexpr,
+static PgBenchExpr *make_op(const char *operator, PgBenchExpr *lexpr,
PgBenchExpr *rexpr);
+static int find_func(const char *fname);
+static PgBenchExpr *make_func(const int fnumber, PgBenchExprList *args);
%}
@@ -31,13 +34,15 @@ static PgBenchExpr *make_op(char operator, PgBenchExpr *lexpr,
int64 ival;
char *str;
PgBenchExpr *expr;
+ PgBenchExprList *elist;
}
+%type <elist> elist
%type <expr> expr
-%type <ival> INTEGER
-%type <str> VARIABLE
+%type <ival> INTEGER function
+%type <str> VARIABLE FUNCTION
-%token INTEGER VARIABLE
+%token INTEGER VARIABLE FUNCTION
%token CHAR_ERROR /* never used, will raise a syntax error */
/* Precedence: lowest to highest */
@@ -49,16 +54,25 @@ static PgBenchExpr *make_op(char operator, PgBenchExpr *lexpr,
result: expr { expr_parse_result = $1; }
+elist: { $$ = NULL; }
+ | expr { $$ = make_elist($1, NULL); }
+ | elist ',' expr { $$ = make_elist($3, $1); }
+ ;
+
expr: '(' expr ')' { $$ = $2; }
| '+' expr %prec UMINUS { $$ = $2; }
- | '-' expr %prec UMINUS { $$ = make_op('-', make_integer_constant(0), $2); }
- | expr '+' expr { $$ = make_op('+', $1, $3); }
- | expr '-' expr { $$ = make_op('-', $1, $3); }
- | expr '*' expr { $$ = make_op('*', $1, $3); }
- | expr '/' expr { $$ = make_op('/', $1, $3); }
- | expr '%' expr { $$ = make_op('%', $1, $3); }
+ | '-' expr %prec UMINUS { $$ = make_op("-", make_integer_constant(0), $2); }
+ | expr '+' expr { $$ = make_op("+", $1, $3); }
+ | expr '-' expr { $$ = make_op("-", $1, $3); }
+ | expr '*' expr { $$ = make_op("*", $1, $3); }
+ | expr '/' expr { $$ = make_op("/", $1, $3); }
+ | expr '%' expr { $$ = make_op("%", $1, $3); }
| INTEGER { $$ = make_integer_constant($1); }
| VARIABLE { $$ = make_variable($1); }
+ | function '(' elist ')'{ $$ = make_func($1, $3); }
+ ;
+
+function: FUNCTION { $$ = find_func($1); pg_free($1); }
;
%%
@@ -84,14 +98,131 @@ make_variable(char *varname)
}
static PgBenchExpr *
-make_op(char operator, PgBenchExpr *lexpr, PgBenchExpr *rexpr)
+make_op(const char *operator, PgBenchExpr *lexpr, PgBenchExpr *rexpr)
+{
+ return make_func(find_func(operator),
+ make_elist(rexpr, make_elist(lexpr, NULL)));
+}
+
+/*
+ * List of available functions:
+ * - fname: function name
+ * - nargs: number of arguments
+ * -1 is a special value for min & max meaning #args >= 1
+ * - tag: function identifier from PgBenchFunction enum
+ */
+static struct
+{
+ char * fname;
+ int nargs;
+ PgBenchFunction tag;
+} PGBENCH_FUNCTIONS[] = {
+ /* parsed as operators, executed as functions */
+ { "+", 2, PGBENCH_ADD },
+ { "-", 2, PGBENCH_SUB },
+ { "*", 2, PGBENCH_MUL },
+ { "/", 2, PGBENCH_DIV },
+ { "%", 2, PGBENCH_MOD },
+ /* actual functions */
+ { "abs", 1, PGBENCH_ABS },
+ { "min", -1, PGBENCH_MIN },
+ { "max", -1, PGBENCH_MAX },
+ { "debug", 1, PGBENCH_DEBUG },
+ /* keep as last array element */
+ { NULL, 0, 0 }
+};
+
+/*
+ * Find a function from its name
+ *
+ * return the index of the function from the PGBENCH_FUNCTIONS array
+ * or fail if the function is unknown.
+ */
+static int
+find_func(const char * fname)
+{
+ int i = 0;
+
+ while (PGBENCH_FUNCTIONS[i].fname)
+ {
+ if (pg_strcasecmp(fname, PGBENCH_FUNCTIONS[i].fname) == 0)
+ return i;
+ i++;
+ }
+
+ expr_yyerror_more("unexpected function name", fname);
+
+ /* not reached */
+ return -1;
+}
+
+/* Expression linked list builder */
+static PgBenchExprList *
+make_elist(PgBenchExpr *expr, PgBenchExprList *list)
+{
+ PgBenchExprLink * cons;
+
+ if (list == NULL)
+ {
+ list = pg_malloc(sizeof(PgBenchExprList));
+ list->head = NULL;
+ list->tail = NULL;
+ }
+
+ cons = pg_malloc(sizeof(PgBenchExprLink));
+ cons->expr = expr;
+ cons->next = NULL;
+
+ if (list->head == NULL)
+ list->head = cons;
+ else
+ list->tail->next = cons;
+
+ list->tail = cons;
+
+ return list;
+}
+
+/* Return the length of an expression list */
+static int
+elist_length(PgBenchExprList *list)
+{
+ PgBenchExprLink *link = list != NULL? list->head: NULL;
+ int len = 0;
+
+ for (; link != NULL; link = link->next)
+ len++;
+
+ return len;
+}
+
+/* Build function call expression */
+static PgBenchExpr *
+make_func(const int fnumber, PgBenchExprList *args)
{
PgBenchExpr *expr = pg_malloc(sizeof(PgBenchExpr));
- expr->etype = ENODE_OPERATOR;
- expr->u.operator.operator = operator;
- expr->u.operator.lexpr = lexpr;
- expr->u.operator.rexpr = rexpr;
+ Assert(fnumber >= 0);
+
+ if (PGBENCH_FUNCTIONS[fnumber].nargs >= 0 &&
+ PGBENCH_FUNCTIONS[fnumber].nargs != elist_length(args))
+ expr_yyerror_more("unexpected number of arguments",
+ PGBENCH_FUNCTIONS[fnumber].fname);
+
+ /* check at least one arg for min & max */
+ if (PGBENCH_FUNCTIONS[fnumber].nargs == -1 &&
+ elist_length(args) == 0)
+ expr_yyerror_more("at least one argument expected",
+ PGBENCH_FUNCTIONS[fnumber].fname);
+
+ expr->etype = ENODE_FUNCTION;
+ expr->u.function.function = PGBENCH_FUNCTIONS[fnumber].tag;
+
+ /* only the link is used, the head/tail is not useful anymore */
+ expr->u.function.args = args != NULL? args->head: NULL;
+ if (args)
+ pg_free(args);
+
return expr;
}
diff --git a/src/bin/pgbench/exprscan.l b/src/bin/pgbench/exprscan.l
index f1c4c7e..7e851f0 100644
--- a/src/bin/pgbench/exprscan.l
+++ b/src/bin/pgbench/exprscan.l
@@ -46,6 +46,7 @@ space [ \t\r\f]
"%" { yycol += yyleng; return '%'; }
"(" { yycol += yyleng; return '('; }
")" { yycol += yyleng; return ')'; }
+"," { yycol += yyleng; return ','; }
:[a-zA-Z0-9_]+ {
yycol += yyleng;
@@ -57,8 +58,14 @@ space [ \t\r\f]
yylval.ival = strtoint64(yytext);
return INTEGER;
}
+[a-zA-Z0-9_]+ {
+ yycol += yyleng;
+ yylval.str = pg_strdup(yytext);
+ return FUNCTION;
+ }
+
+[\n] { yycol = 0; yyline++; /* never occurs, input on one line */ }
-[\n] { yycol = 0; yyline++; }
{space}+ { yycol += yyleng; /* ignore */ }
. {
@@ -71,10 +78,16 @@ space [ \t\r\f]
%%
void
-yyerror(const char *message)
+expr_yyerror_more(const char *message, const char *more)
{
syntax_error(expr_source, expr_lineno, expr_full_line, expr_command,
- message, NULL, expr_col + yycol);
+ message, more, expr_col + yycol);
+}
+
+void
+yyerror(const char *message)
+{
+ expr_yyerror_more(message, NULL);
}
/*
@@ -94,6 +107,9 @@ expr_scanner_init(const char *str, const char *source,
expr_command = (char *) cmd;
expr_col = (int) ecol;
+ /* reset column count for this scan */
+ yycol = 0;
+
/*
* Might be left over after error
*/
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index 596d112..da128bf 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -372,6 +372,8 @@ static void doLog(TState *thread, CState *st, instr_time *now,
StatsData *agg, bool skipped, double latency, double lag);
+static bool evaluateExpr(CState *, PgBenchExpr *, int64 *);
+
static void
usage(void)
{
@@ -990,6 +992,146 @@ getQueryParams(CState *st, const Command *command, const char **params)
params[i] = getVariable(st, command->argv[i + 1]);
}
+/* Recursive evaluation of functions
+ */
+static bool
+evalFunc(CState *st,
+ PgBenchFunction func, PgBenchExprLink *args, int64 *retval)
+{
+ switch (func)
+ {
+ case PGBENCH_ADD:
+ case PGBENCH_SUB:
+ case PGBENCH_MUL:
+ case PGBENCH_DIV:
+ case PGBENCH_MOD:
+ {
+ int64 lval, rval;
+
+ if (!args || !args->next || args->next->next)
+ /* two arguments only */
+ return false;
+
+ if (!evaluateExpr(st, args->expr, &lval))
+ return false;
+
+ if (!evaluateExpr(st, args->next->expr, &rval))
+ return false;
+
+ switch (func)
+ {
+ case PGBENCH_ADD:
+ *retval = lval + rval;
+ return true;
+
+ case PGBENCH_SUB:
+ *retval = lval - rval;
+ return true;
+
+ case PGBENCH_MUL:
+ *retval = lval * rval;
+ return true;
+
+ case PGBENCH_DIV:
+ case PGBENCH_MOD:
+ if (rval == 0)
+ {
+ fprintf(stderr, "division by zero\n");
+ return false;
+ }
+ /* special handling of -1 divisor */
+ if (rval == -1)
+ {
+ if (func == PGBENCH_DIV)
+ {
+ /* overflow check (needed for INT64_MIN) */
+ if (lval == PG_INT64_MIN)
+ {
+ fprintf(stderr, "bigint out of range\n");
+ return false;
+ }
+ else
+ *retval = -lval;
+ }
+ else if (func == PGBENCH_MOD)
+ *retval = 0;
+ else
+ /* this cannot happend */
+ Assert(0);
+ return true;
+ }
+ /* divisor is not -1 */
+ if (func == PGBENCH_DIV)
+ *retval = lval / rval;
+ else /* func == PGBENCH_MOD */
+ *retval = lval % rval;
+ return true;
+
+ default:
+ /* cannot get here */
+ Assert(0);
+ }
+ }
+
+ case PGBENCH_ABS:
+ {
+ if (!evaluateExpr(st, args->expr, retval))
+ return false;
+
+ if (*retval < 0)
+ *retval = - *retval;
+
+ return true;
+ }
+
+ case PGBENCH_DEBUG:
+ {
+ if (!evaluateExpr(st, args->expr, retval))
+ return false;
+
+ fprintf(stderr, "debug(script=%d,command=%d): "INT64_FORMAT"\n",
+ st->use_file, st->state+1, *retval);
+
+ return true;
+ }
+
+ case PGBENCH_MIN:
+ case PGBENCH_MAX:
+ {
+ int64 extremum = -1;
+ bool first = true;
+
+ while (args != NULL)
+ {
+ int64 ival;
+
+ if (!evaluateExpr(st, args->expr, &ival))
+ return false;
+
+ if (first)
+ extremum = ival;
+ else
+ {
+ if (func == PGBENCH_MIN)
+ extremum = extremum < ival? extremum: ival;
+ else if (func == PGBENCH_MAX)
+ extremum = extremum > ival? extremum: ival;
+ }
+
+ args = args->next;
+ first = false;
+ }
+
+ *retval = extremum;
+ return true;
+ }
+
+ default:
+ fprintf(stderr, "unexpected function tag: %d\n", func);
+ exit(1);
+ }
+}
+
/*
* Recursive evaluation of an expression in a pgbench script
* using the current state of variables.
@@ -1021,86 +1163,16 @@ evaluateExpr(CState *st, PgBenchExpr *expr, int64 *retval)
return true;
}
- case ENODE_OPERATOR:
- {
- int64 lval;
- int64 rval;
-
- if (!evaluateExpr(st, expr->u.operator.lexpr, &lval))
- return false;
- if (!evaluateExpr(st, expr->u.operator.rexpr, &rval))
- return false;
- switch (expr->u.operator.operator)
- {
- case '+':
- *retval = lval + rval;
- return true;
-
- case '-':
- *retval = lval - rval;
- return true;
-
- case '*':
- *retval = lval * rval;
- return true;
-
- case '/':
- if (rval == 0)
- {
- fprintf(stderr, "division by zero\n");
- return false;
- }
-
- /*
- * INT64_MIN / -1 is problematic, since the result
- * can't be represented on a two's-complement machine.
- * Some machines produce INT64_MIN, some produce zero,
- * some throw an exception. We can dodge the problem
- * by recognizing that division by -1 is the same as
- * negation.
- */
- if (rval == -1)
- {
- *retval = -lval;
-
- /* overflow check (needed for INT64_MIN) */
- if (lval == PG_INT64_MIN)
- {
- fprintf(stderr, "bigint out of range\n");
- return false;
- }
- }
- else
- *retval = lval / rval;
-
- return true;
-
- case '%':
- if (rval == 0)
- {
- fprintf(stderr, "division by zero\n");
- return false;
- }
-
- /*
- * Some machines throw a floating-point exception for
- * INT64_MIN % -1. Dodge that problem by noting that
- * any value modulo -1 is 0.
- */
- if (rval == -1)
- *retval = 0;
- else
- *retval = lval % rval;
-
- return true;
- }
-
- fprintf(stderr, "bad operator\n");
- return false;
- }
+ case ENODE_FUNCTION:
+ return evalFunc(st,
+ expr->u.function.function,
+ expr->u.function.args,
+ retval);
default:
- break;
+ fprintf(stderr, "unexpected enode type in evaluation: %d\n",
+ expr->etype);
+ exit(1);
}
fprintf(stderr, "bad expression\n");
@@ -1710,6 +1782,7 @@ top:
st->ecnt++;
return true;
}
+
sprintf(res, INT64_FORMAT, result);
if (!putVariable(st, argv[0], argv[1], res))
diff --git a/src/bin/pgbench/pgbench.h b/src/bin/pgbench/pgbench.h
index 5bb2480..32ed699 100644
--- a/src/bin/pgbench/pgbench.h
+++ b/src/bin/pgbench/pgbench.h
@@ -11,15 +11,39 @@
#ifndef PGBENCH_H
#define PGBENCH_H
+/* Types of expression nodes */
typedef enum PgBenchExprType
{
ENODE_INTEGER_CONSTANT,
ENODE_VARIABLE,
- ENODE_OPERATOR
+ ENODE_FUNCTION
} PgBenchExprType;
+/* List of operators and callable functions */
+typedef enum PgBenchFunction
+{
+ PGBENCH_ADD,
+ PGBENCH_SUB,
+ PGBENCH_MUL,
+ PGBENCH_DIV,
+ PGBENCH_MOD,
+ PGBENCH_DEBUG,
+ PGBENCH_ABS,
+ PGBENCH_MIN,
+ PGBENCH_MAX,
+} PgBenchFunction;
+
typedef struct PgBenchExpr PgBenchExpr;
+typedef struct PgBenchExprLink PgBenchExprLink;
+typedef struct PgBenchExprList PgBenchExprList;
+/*
+ * Basic representation of an expression parsed. This can be used as
+ * different things by the parser as defined by PgBenchExprType:
+ * - ENODE_CONSTANT, constant integer or double value
+ * - ENODE_VARIABLE, variable result of \set or \setrandom
+ * - ENODE_FUNCTION, in-core functions and operators
+ */
struct PgBenchExpr
{
PgBenchExprType etype;
@@ -35,18 +59,31 @@ struct PgBenchExpr
} variable;
struct
{
- char operator;
- PgBenchExpr *lexpr;
- PgBenchExpr *rexpr;
- } operator;
+ PgBenchFunction function;
+ PgBenchExprLink *args;
+ } function;
} u;
};
+/* List of expression nodes */
+struct PgBenchExprLink
+{
+ PgBenchExpr *expr;
+ PgBenchExprLink *next;
+};
+
+struct PgBenchExprList
+{
+ PgBenchExprLink *head;
+ PgBenchExprLink *tail;
+};
+
extern PgBenchExpr *expr_parse_result;
extern int expr_yyparse(void);
extern int expr_yylex(void);
extern void expr_yyerror(const char *str);
+extern void expr_yyerror_more(const char *str, const char *more);
extern void expr_scanner_init(const char *str, const char *source,
const int lineno, const char *line,
const char *cmd, const int ecol);
diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index ade1b53..f39f341 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -786,7 +786,7 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
</para>
<variablelist>
- <varlistentry>
+ <varlistentry id='pgbench-metacommand-set'>
<term>
<literal>\set <replaceable>varname</> <replaceable>expression</></literal>
</term>
@@ -798,8 +798,10 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
The expression may contain integer constants such as <literal>5432</>,
references to variables <literal>:</><replaceable>variablename</>,
and expressions composed of unary (<literal>-</>) or binary operators
- (<literal>+</>, <literal>-</>, <literal>*</>, <literal>/</>, <literal>%</>)
- with their usual associativity, and parentheses.
+ (<literal>+</>, <literal>-</>, <literal>*</>, <literal>/</>,
+ <literal>%</>) with their usual associativity,
+ <link linkend="pgbench-builtin-functions">function calls</>, and
+ parentheses.
</para>
<para>
@@ -994,6 +996,62 @@ END;
</refsect2>
+ <refsect2 id="pgbench-builtin-functions">
+ <title>Built-In Functions</title>
+
+ <para>
+ The following functions are built into <application>pgbench</> and
+ may be used in conjunction with
+ <link linkend="pgbench-metacommand-set"><literal>\set</literal></link>.
+ </para>
+
+ <!-- list pgbench functions in alphabetical order -->
+ <table>
+ <title>pgbench Functions</title>
+ <tgroup cols="5">
+ <thead>
+ <row>
+ <entry>Function</entry>
+ <entry>Return Type</entry>
+ <entry>Description</entry>
+ <entry>Example</entry>
+ <entry>Result</entry>
+ </row>
+ </thead>
+ <tbody>
+ <row>
+ <entry><literal><function>abs(<replaceable>a</>)</></></>
+ <entry>same as <replaceable>a</></>
+ <entry>integer value</>
+ <entry><literal>abs(-17)</></>
+ <entry><literal>17</></>
+ </row>
+ <row>
+ <entry><literal><function>debug(<replaceable>a</>)</></></>
+ <entry>same as <replaceable>a</> </>
+ <entry>print to <systemitem>stderr</systemitem> the given argument</>
+ <entry><literal>debug(5432)</></>
+ <entry><literal>5432</></>
+ </row>
+ <row>
+ <entry><literal><function>max(<replaceable>i</> [, <replaceable>...</> ] )</></></>
+ <entry>integer</>
+ <entry>maximum value</>
+ <entry><literal>max(5, 4, 3, 2)</></>
+ <entry><literal>5</></>
+ </row>
+ <row>
+ <entry><literal><function>min(<replaceable>i</> [, <replaceable>...</> ] )</></></>
+ <entry>integer</>
+ <entry>minimum value</>
+ <entry><literal>min(5, 4, 3, 2)</></>
+ <entry><literal>2</></>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+ </refsect2>
+
<refsect2>
<title>Per-Transaction Logging</title>
diff --git a/src/bin/pgbench/exprparse.y b/src/bin/pgbench/exprparse.y
index 06ee04b..cac4d5e 100644
--- a/src/bin/pgbench/exprparse.y
+++ b/src/bin/pgbench/exprparse.y
@@ -16,10 +16,13 @@
PgBenchExpr *expr_parse_result;
+static PgBenchExprList *make_elist(PgBenchExpr *exp, PgBenchExprList *list);
static PgBenchExpr *make_integer_constant(int64 ival);
static PgBenchExpr *make_variable(char *varname);
-static PgBenchExpr *make_op(char operator, PgBenchExpr *lexpr,
+static PgBenchExpr *make_op(const char *operator, PgBenchExpr *lexpr,
PgBenchExpr *rexpr);
+static int find_func(const char *fname);
+static PgBenchExpr *make_func(const int fnumber, PgBenchExprList *args);
%}
@@ -31,13 +34,15 @@ static PgBenchExpr *make_op(char operator, PgBenchExpr *lexpr,
int64 ival;
char *str;
PgBenchExpr *expr;
+ PgBenchExprList *elist;
}
+%type <elist> elist
%type <expr> expr
-%type <ival> INTEGER
-%type <str> VARIABLE
+%type <ival> INTEGER function
+%type <str> VARIABLE FUNCTION
-%token INTEGER VARIABLE
+%token INTEGER VARIABLE FUNCTION
%token CHAR_ERROR /* never used, will raise a syntax error */
/* Precedence: lowest to highest */
@@ -49,16 +54,25 @@ static PgBenchExpr *make_op(char operator, PgBenchExpr *lexpr,
result: expr { expr_parse_result = $1; }
+elist: { $$ = NULL; }
+ | expr { $$ = make_elist($1, NULL); }
+ | elist ',' expr { $$ = make_elist($3, $1); }
+ ;
+
expr: '(' expr ')' { $$ = $2; }
| '+' expr %prec UMINUS { $$ = $2; }
- | '-' expr %prec UMINUS { $$ = make_op('-', make_integer_constant(0), $2); }
- | expr '+' expr { $$ = make_op('+', $1, $3); }
- | expr '-' expr { $$ = make_op('-', $1, $3); }
- | expr '*' expr { $$ = make_op('*', $1, $3); }
- | expr '/' expr { $$ = make_op('/', $1, $3); }
- | expr '%' expr { $$ = make_op('%', $1, $3); }
+ | '-' expr %prec UMINUS { $$ = make_op("-", make_integer_constant(0), $2); }
+ | expr '+' expr { $$ = make_op("+", $1, $3); }
+ | expr '-' expr { $$ = make_op("-", $1, $3); }
+ | expr '*' expr { $$ = make_op("*", $1, $3); }
+ | expr '/' expr { $$ = make_op("/", $1, $3); }
+ | expr '%' expr { $$ = make_op("%", $1, $3); }
| INTEGER { $$ = make_integer_constant($1); }
| VARIABLE { $$ = make_variable($1); }
+ | function '(' elist ')'{ $$ = make_func($1, $3); }
+ ;
+
+function: FUNCTION { $$ = find_func($1); pg_free($1); }
;
%%
@@ -84,14 +98,131 @@ make_variable(char *varname)
}
static PgBenchExpr *
-make_op(char operator, PgBenchExpr *lexpr, PgBenchExpr *rexpr)
+make_op(const char *operator, PgBenchExpr *lexpr, PgBenchExpr *rexpr)
+{
+ return make_func(find_func(operator),
+ make_elist(rexpr, make_elist(lexpr, NULL)));
+}
+
+/*
+ * List of available functions:
+ * - fname: function name
+ * - nargs: number of arguments
+ * -1 is a special value for min & max meaning #args >= 1
+ * - tag: function identifier from PgBenchFunction enum
+ */
+static struct
+{
+ char * fname;
+ int nargs;
+ PgBenchFunction tag;
+} PGBENCH_FUNCTIONS[] = {
+ /* parsed as operators, executed as functions */
+ { "+", 2, PGBENCH_ADD },
+ { "-", 2, PGBENCH_SUB },
+ { "*", 2, PGBENCH_MUL },
+ { "/", 2, PGBENCH_DIV },
+ { "%", 2, PGBENCH_MOD },
+ /* actual functions */
+ { "abs", 1, PGBENCH_ABS },
+ { "min", -1, PGBENCH_MIN },
+ { "max", -1, PGBENCH_MAX },
+ { "debug", 1, PGBENCH_DEBUG },
+ /* keep as last array element */
+ { NULL, 0, 0 }
+};
+
+/*
+ * Find a function from its name
+ *
+ * return the index of the function from the PGBENCH_FUNCTIONS array
+ * or fail if the function is unknown.
+ */
+static int
+find_func(const char * fname)
+{
+ int i = 0;
+
+ while (PGBENCH_FUNCTIONS[i].fname)
+ {
+ if (pg_strcasecmp(fname, PGBENCH_FUNCTIONS[i].fname) == 0)
+ return i;
+ i++;
+ }
+
+ expr_yyerror_more("unexpected function name", fname);
+
+ /* not reached */
+ return -1;
+}
+
+/* Expression linked list builder */
+static PgBenchExprList *
+make_elist(PgBenchExpr *expr, PgBenchExprList *list)
+{
+ PgBenchExprLink * cons;
+
+ if (list == NULL)
+ {
+ list = pg_malloc(sizeof(PgBenchExprList));
+ list->head = NULL;
+ list->tail = NULL;
+ }
+
+ cons = pg_malloc(sizeof(PgBenchExprLink));
+ cons->expr = expr;
+ cons->next = NULL;
+
+ if (list->head == NULL)
+ list->head = cons;
+ else
+ list->tail->next = cons;
+
+ list->tail = cons;
+
+ return list;
+}
+
+/* Return the length of an expression list */
+static int
+elist_length(PgBenchExprList *list)
+{
+ PgBenchExprLink *link = list != NULL? list->head: NULL;
+ int len = 0;
+
+ for (; link != NULL; link = link->next)
+ len++;
+
+ return len;
+}
+
+/* Build function call expression */
+static PgBenchExpr *
+make_func(const int fnumber, PgBenchExprList *args)
{
PgBenchExpr *expr = pg_malloc(sizeof(PgBenchExpr));
- expr->etype = ENODE_OPERATOR;
- expr->u.operator.operator = operator;
- expr->u.operator.lexpr = lexpr;
- expr->u.operator.rexpr = rexpr;
+ Assert(fnumber >= 0);
+
+ if (PGBENCH_FUNCTIONS[fnumber].nargs >= 0 &&
+ PGBENCH_FUNCTIONS[fnumber].nargs != elist_length(args))
+ expr_yyerror_more("unexpected number of arguments",
+ PGBENCH_FUNCTIONS[fnumber].fname);
+
+ /* check at least one arg for min & max */
+ if (PGBENCH_FUNCTIONS[fnumber].nargs == -1 &&
+ elist_length(args) == 0)
+ expr_yyerror_more("at least one argument expected",
+ PGBENCH_FUNCTIONS[fnumber].fname);
+
+ expr->etype = ENODE_FUNCTION;
+ expr->u.function.function = PGBENCH_FUNCTIONS[fnumber].tag;
+
+ /* only the link is used, the head/tail is not useful anymore */
+ expr->u.function.args = args != NULL? args->head: NULL;
+ if (args)
+ pg_free(args);
+
return expr;
}
diff --git a/src/bin/pgbench/exprscan.l b/src/bin/pgbench/exprscan.l
index f1c4c7e..7e851f0 100644
--- a/src/bin/pgbench/exprscan.l
+++ b/src/bin/pgbench/exprscan.l
@@ -46,6 +46,7 @@ space [ \t\r\f]
"%" { yycol += yyleng; return '%'; }
"(" { yycol += yyleng; return '('; }
")" { yycol += yyleng; return ')'; }
+"," { yycol += yyleng; return ','; }
:[a-zA-Z0-9_]+ {
yycol += yyleng;
@@ -57,8 +58,14 @@ space [ \t\r\f]
yylval.ival = strtoint64(yytext);
return INTEGER;
}
+[a-zA-Z0-9_]+ {
+ yycol += yyleng;
+ yylval.str = pg_strdup(yytext);
+ return FUNCTION;
+ }
+
+[\n] { yycol = 0; yyline++; /* never occurs, input on one line */ }
-[\n] { yycol = 0; yyline++; }
{space}+ { yycol += yyleng; /* ignore */ }
. {
@@ -71,10 +78,16 @@ space [ \t\r\f]
%%
void
-yyerror(const char *message)
+expr_yyerror_more(const char *message, const char *more)
{
syntax_error(expr_source, expr_lineno, expr_full_line, expr_command,
- message, NULL, expr_col + yycol);
+ message, more, expr_col + yycol);
+}
+
+void
+yyerror(const char *message)
+{
+ expr_yyerror_more(message, NULL);
}
/*
@@ -94,6 +107,9 @@ expr_scanner_init(const char *str, const char *source,
expr_command = (char *) cmd;
expr_col = (int) ecol;
+ /* reset column count for this scan */
+ yycol = 0;
+
/*
* Might be left over after error
*/
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index 596d112..eed105c 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -372,6 +372,8 @@ static void doLog(TState *thread, CState *st, instr_time *now,
StatsData *agg, bool skipped, double latency, double lag);
+static bool evaluateExpr(CState *, PgBenchExpr *, int64 *);
+
static void
usage(void)
{
@@ -990,6 +992,150 @@ getQueryParams(CState *st, const Command *command, const char **params)
params[i] = getVariable(st, command->argv[i + 1]);
}
+/* maximum number of function arguments */
+#define MAX_FARGS 16
+
+/*
+ * Recursive evaluation of functions
+ */
+static bool
+evalFunc(CState *st,
+ PgBenchFunction func, PgBenchExprLink *args, int64 *retval)
+{
+ /* evaluate all function arguments */
+ int nargs = 0;
+ int64 iargs[MAX_FARGS];
+ PgBenchExprLink *l = args;
+
+ for (nargs = 0; nargs < MAX_FARGS && l != NULL; nargs++, l = l->next)
+ if (!evaluateExpr(st, l->expr, &iargs[nargs]))
+ return false;
+
+ if (l != NULL)
+ {
+ fprintf(stderr,
+ "too many function arguments, maximum is %d\n", MAX_FARGS);
+ return false;
+ }
+
+ /* then evaluate function */
+ switch (func)
+ {
+ case PGBENCH_ADD:
+ case PGBENCH_SUB:
+ case PGBENCH_MUL:
+ case PGBENCH_DIV:
+ case PGBENCH_MOD:
+ {
+ int lval = iargs[0], rval = iargs[1];
+ Assert(nargs == 2);
+
+ switch (func)
+ {
+ case PGBENCH_ADD:
+ *retval = lval + rval;
+ return true;
+
+ case PGBENCH_SUB:
+ *retval = lval - rval;
+ return true;
+
+ case PGBENCH_MUL:
+ *retval = lval * rval;
+ return true;
+
+ case PGBENCH_DIV:
+ case PGBENCH_MOD:
+ if (rval == 0)
+ {
+ fprintf(stderr, "division by zero\n");
+ return false;
+ }
+ /* special handling of -1 divisor */
+ if (rval == -1)
+ {
+ if (func == PGBENCH_DIV)
+ {
+ /* overflow check (needed for INT64_MIN) */
+ if (lval == PG_INT64_MIN)
+ {
+ fprintf(stderr, "bigint out of range\n");
+ return false;
+ }
+ else
+ *retval = -lval;
+ }
+ else if (func == PGBENCH_MOD)
+ *retval = 0;
+ else
+ /* this cannot happend */
+ Assert(0);
+ return true;
+ }
+ /* divisor is not -1 */
+ if (func == PGBENCH_DIV)
+ *retval = lval / rval;
+ else /* func == PGBENCH_MOD */
+ *retval = lval % rval;
+ return true;
+
+ default:
+ /* cannot get here */
+ Assert(0);
+ }
+ }
+
+ case PGBENCH_ABS:
+ {
+ Assert(nargs == 1);
+
+ if (iargs[0] < 0)
+ *retval = - iargs[0];
+ else
+ *retval = iargs[0];
+
+ return true;
+ }
+
+ case PGBENCH_DEBUG:
+ {
+ Assert(nargs == 1);
+
+ fprintf(stderr, "debug(script=%d,command=%d): "INT64_FORMAT"\n",
+ st->use_file, st->state+1, iargs[0]);
+
+ *retval = iargs[0];
+
+ return true;
+ }
+
+ case PGBENCH_MIN:
+ case PGBENCH_MAX:
+ {
+ int64 extremum = iargs[0];
+ int i;
+ Assert(nargs >= 1);
+
+ for (i = 1; i < nargs; i++)
+ {
+ int64 ival = iargs[i];
+
+ if (func == PGBENCH_MIN)
+ extremum = extremum < ival? extremum: ival;
+ else if (func == PGBENCH_MAX)
+ extremum = extremum > ival? extremum: ival;
+ }
+
+ *retval = extremum;
+ return true;
+ }
+
+ default:
+ fprintf(stderr, "unexpected function tag: %d\n", func);
+ exit(1);
+ }
+}
+
/*
* Recursive evaluation of an expression in a pgbench script
* using the current state of variables.
@@ -1021,86 +1167,16 @@ evaluateExpr(CState *st, PgBenchExpr *expr, int64 *retval)
return true;
}
- case ENODE_OPERATOR:
- {
- int64 lval;
- int64 rval;
-
- if (!evaluateExpr(st, expr->u.operator.lexpr, &lval))
- return false;
- if (!evaluateExpr(st, expr->u.operator.rexpr, &rval))
- return false;
- switch (expr->u.operator.operator)
- {
- case '+':
- *retval = lval + rval;
- return true;
-
- case '-':
- *retval = lval - rval;
- return true;
-
- case '*':
- *retval = lval * rval;
- return true;
-
- case '/':
- if (rval == 0)
- {
- fprintf(stderr, "division by zero\n");
- return false;
- }
-
- /*
- * INT64_MIN / -1 is problematic, since the result
- * can't be represented on a two's-complement machine.
- * Some machines produce INT64_MIN, some produce zero,
- * some throw an exception. We can dodge the problem
- * by recognizing that division by -1 is the same as
- * negation.
- */
- if (rval == -1)
- {
- *retval = -lval;
-
- /* overflow check (needed for INT64_MIN) */
- if (lval == PG_INT64_MIN)
- {
- fprintf(stderr, "bigint out of range\n");
- return false;
- }
- }
- else
- *retval = lval / rval;
-
- return true;
-
- case '%':
- if (rval == 0)
- {
- fprintf(stderr, "division by zero\n");
- return false;
- }
-
- /*
- * Some machines throw a floating-point exception for
- * INT64_MIN % -1. Dodge that problem by noting that
- * any value modulo -1 is 0.
- */
- if (rval == -1)
- *retval = 0;
- else
- *retval = lval % rval;
-
- return true;
- }
-
- fprintf(stderr, "bad operator\n");
- return false;
- }
+ case ENODE_FUNCTION:
+ return evalFunc(st,
+ expr->u.function.function,
+ expr->u.function.args,
+ retval);
default:
- break;
+ fprintf(stderr, "unexpected enode type in evaluation: %d\n",
+ expr->etype);
+ exit(1);
}
fprintf(stderr, "bad expression\n");
@@ -1710,6 +1786,7 @@ top:
st->ecnt++;
return true;
}
+
sprintf(res, INT64_FORMAT, result);
if (!putVariable(st, argv[0], argv[1], res))
diff --git a/src/bin/pgbench/pgbench.h b/src/bin/pgbench/pgbench.h
index 5bb2480..32ed699 100644
--- a/src/bin/pgbench/pgbench.h
+++ b/src/bin/pgbench/pgbench.h
@@ -11,15 +11,39 @@
#ifndef PGBENCH_H
#define PGBENCH_H
+/* Types of expression nodes */
typedef enum PgBenchExprType
{
ENODE_INTEGER_CONSTANT,
ENODE_VARIABLE,
- ENODE_OPERATOR
+ ENODE_FUNCTION
} PgBenchExprType;
+/* List of operators and callable functions */
+typedef enum PgBenchFunction
+{
+ PGBENCH_ADD,
+ PGBENCH_SUB,
+ PGBENCH_MUL,
+ PGBENCH_DIV,
+ PGBENCH_MOD,
+ PGBENCH_DEBUG,
+ PGBENCH_ABS,
+ PGBENCH_MIN,
+ PGBENCH_MAX,
+} PgBenchFunction;
+
typedef struct PgBenchExpr PgBenchExpr;
+typedef struct PgBenchExprLink PgBenchExprLink;
+typedef struct PgBenchExprList PgBenchExprList;
+/*
+ * Basic representation of an expression parsed. This can be used as
+ * different things by the parser as defined by PgBenchExprType:
+ * - ENODE_CONSTANT, constant integer or double value
+ * - ENODE_VARIABLE, variable result of \set or \setrandom
+ * - ENODE_FUNCTION, in-core functions and operators
+ */
struct PgBenchExpr
{
PgBenchExprType etype;
@@ -35,18 +59,31 @@ struct PgBenchExpr
} variable;
struct
{
- char operator;
- PgBenchExpr *lexpr;
- PgBenchExpr *rexpr;
- } operator;
+ PgBenchFunction function;
+ PgBenchExprLink *args;
+ } function;
} u;
};
+/* List of expression nodes */
+struct PgBenchExprLink
+{
+ PgBenchExpr *expr;
+ PgBenchExprLink *next;
+};
+
+struct PgBenchExprList
+{
+ PgBenchExprLink *head;
+ PgBenchExprLink *tail;
+};
+
extern PgBenchExpr *expr_parse_result;
extern int expr_yyparse(void);
extern int expr_yylex(void);
extern void expr_yyerror(const char *str);
+extern void expr_yyerror_more(const char *str, const char *more);
extern void expr_scanner_init(const char *str, const char *source,
const int lineno, const char *line,
const char *cmd, const int ecol);
--
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