diff options
author | Robert Haas | 2016-03-01 18:04:09 +0000 |
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committer | Robert Haas | 2016-03-01 18:08:30 +0000 |
commit | 7e137f846df2431ce9c61202dcea21ee4a6d7822 (patch) | |
tree | dc4119bd7990deb5142971d5918885acc35859a4 | |
parent | bd6cf3f237c9aeb4dad1ac3ec2008c5768fe4c1b (diff) |
Extend pgbench's expression syntax to support a few built-in functions.
Fabien Coelho, reviewed mostly by Michael Paquier and me, but also by
Heikki Linnakangas, BeomYong Lee, Kyotaro Horiguchi, Oleksander
Shulgin, and Álvaro Herrera.
-rw-r--r-- | doc/src/sgml/ref/pgbench.sgml | 64 | ||||
-rw-r--r-- | src/bin/pgbench/exprparse.y | 161 | ||||
-rw-r--r-- | src/bin/pgbench/exprscan.l | 20 | ||||
-rw-r--r-- | src/bin/pgbench/pgbench.c | 221 | ||||
-rw-r--r-- | src/bin/pgbench/pgbench.h | 40 |
5 files changed, 409 insertions, 97 deletions
diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml index ade1b530d2..f39f341a26 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 06ee04b687..cac4d5e4f4 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 f1c4c7e514..df673f09f2 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++; } + {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 596d112d5b..66cfdc9af8 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) { @@ -990,117 +992,191 @@ 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 an expression in a pgbench script - * using the current state of variables. - * Returns whether the evaluation was ok, - * the value itself is returned through the retval pointer. + * Recursive evaluation of functions */ static bool -evaluateExpr(CState *st, PgBenchExpr *expr, int64 *retval) +evalFunc(CState *st, + PgBenchFunction func, PgBenchExprLink *args, int64 *retval) { - switch (expr->etype) - { - case ENODE_INTEGER_CONSTANT: - { - *retval = expr->u.integer_constant.ival; - return true; - } + /* evaluate all function arguments */ + int nargs = 0; + int64 iargs[MAX_FARGS]; + PgBenchExprLink *l = args; - case ENODE_VARIABLE: - { - char *var; + for (nargs = 0; nargs < MAX_FARGS && l != NULL; nargs++, l = l->next) + if (!evaluateExpr(st, l->expr, &iargs[nargs])) + return false; - if ((var = getVariable(st, expr->u.variable.varname)) == NULL) - { - fprintf(stderr, "undefined variable \"%s\"\n", - expr->u.variable.varname); - return false; - } - *retval = strtoint64(var); - return true; - } + if (l != NULL) + { + fprintf(stderr, + "too many function arguments, maximum is %d\n", MAX_FARGS); + return false; + } - case ENODE_OPERATOR: + /* then evaluate function */ + switch (func) + { + case PGBENCH_ADD: + case PGBENCH_SUB: + case PGBENCH_MUL: + case PGBENCH_DIV: + case PGBENCH_MOD: { - int64 lval; - int64 rval; + int64 lval = iargs[0], + rval = iargs[1]; - 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) + Assert(nargs == 2); + + switch (func) { - case '+': + case PGBENCH_ADD: *retval = lval + rval; return true; - case '-': + case PGBENCH_SUB: *retval = lval - rval; return true; - case '*': + case PGBENCH_MUL: *retval = lval * rval; return true; - case '/': + case PGBENCH_DIV: + case PGBENCH_MOD: 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. - */ + /* special handling of -1 divisor */ if (rval == -1) { - *retval = -lval; - - /* overflow check (needed for INT64_MIN) */ - if (lval == PG_INT64_MIN) + if (func == PGBENCH_DIV) { - fprintf(stderr, "bigint out of range\n"); - return false; + /* overflow check (needed for INT64_MIN) */ + if (lval == PG_INT64_MIN) + { + fprintf(stderr, "bigint out of range\n"); + return false; + } + else + *retval = -lval; } + else + *retval = 0; + return true; } - else + /* divisor is not -1 */ + if (func == PGBENCH_DIV) *retval = lval / rval; - + else /* func == PGBENCH_MOD */ + *retval = lval % rval; return true; - case '%': - if (rval == 0) - { - fprintf(stderr, "division by zero\n"); - return false; - } + default: + /* cannot get here */ + Assert(0); + } + } - /* - * 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; + case PGBENCH_ABS: + { + Assert(nargs == 1); - return true; + 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; } - fprintf(stderr, "bad operator\n"); - return false; + *retval = extremum; + return true; } default: - break; + 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. + * Returns whether the evaluation was ok, + * the value itself is returned through the retval pointer. + */ +static bool +evaluateExpr(CState *st, PgBenchExpr *expr, int64 *retval) +{ + switch (expr->etype) + { + case ENODE_INTEGER_CONSTANT: + { + *retval = expr->u.integer_constant.ival; + return true; + } + + case ENODE_VARIABLE: + { + char *var; + + if ((var = getVariable(st, expr->u.variable.varname)) == NULL) + { + fprintf(stderr, "undefined variable \"%s\"\n", + expr->u.variable.varname); + return false; + } + *retval = strtoint64(var); + return true; + } + + case ENODE_FUNCTION: + return evalFunc(st, + expr->u.function.function, + expr->u.function.args, + retval); + + default: + 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 5bb24807c1..c6aeb5b6db 100644 --- a/src/bin/pgbench/pgbench.h +++ b/src/bin/pgbench/pgbench.h @@ -11,14 +11,31 @@ #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; struct PgBenchExpr { @@ -35,18 +52,31 @@ 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); |