pgbench: replace run-time string comparisons with an enum identifier.

Minor refactoring that should yield some performance benefit.

Fabien Coelho, reviewed by Aleksandr Parfenov

Discussion: https://postgr.es/m/alpine.DEB.2.20.1709230538130.4999@lancre

diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index 5d8a01c72cf639878f59f07e1171da385ab1824b..d4a60351a86f45cf565e204c6c62e69a51c80431 100644 (file)
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -362,6 +362,15 @@ typedef struct
 #define META_COMMAND   2
 #define MAX_ARGS       10
 
+typedef enum MetaCommand
+{
+   META_NONE,                  /* not a known meta-command */
+   META_SET,                   /* \set */
+   META_SETSHELL,              /* \setshell */
+   META_SHELL,                 /* \shell */
+   META_SLEEP                  /* \sleep */
+} MetaCommand;
+
 typedef enum QueryMode
 {
    QUERY_SIMPLE,               /* simple query */
@@ -378,6 +387,7 @@ typedef struct
    char       *line;           /* text of command line */
    int         command_num;    /* unique index of this Command struct */
    int         type;           /* command type (SQL_COMMAND or META_COMMAND) */
+   MetaCommand meta;           /* meta command identifier, or META_NONE */
    int         argc;           /* number of command words */
    char       *argv[MAX_ARGS]; /* command word list */
    PgBenchExpr *expr;          /* parsed expression, if needed */
@@ -1721,6 +1731,29 @@ evaluateExpr(TState *thread, CState *st, PgBenchExpr *expr, PgBenchValue *retval
    }
 }
 
+/*
+ * Convert command name to meta-command enum identifier
+ */
+static MetaCommand
+getMetaCommand(const char *cmd)
+{
+   MetaCommand mc;
+
+   if (cmd == NULL)
+       mc = META_NONE;
+   else if (pg_strcasecmp(cmd, "set") == 0)
+       mc = META_SET;
+   else if (pg_strcasecmp(cmd, "setshell") == 0)
+       mc = META_SETSHELL;
+   else if (pg_strcasecmp(cmd, "shell") == 0)
+       mc = META_SHELL;
+   else if (pg_strcasecmp(cmd, "sleep") == 0)
+       mc = META_SLEEP;
+   else
+       mc = META_NONE;
+   return mc;
+}
+
 /*
  * Run a shell command. The result is assigned to the variable if not NULL.
  * Return true if succeeded, or false on error.
@@ -2214,7 +2247,7 @@ doCustom(TState *thread, CState *st, StatsData *agg)
                        fprintf(stderr, "\n");
                    }
 
-                   if (pg_strcasecmp(argv[0], "sleep") == 0)
+                   if (command->meta == META_SLEEP)
                    {
                        /*
                         * A \sleep doesn't execute anything, we just get the
@@ -2240,7 +2273,7 @@ doCustom(TState *thread, CState *st, StatsData *agg)
                    }
                    else
                    {
-                       if (pg_strcasecmp(argv[0], "set") == 0)
+                       if (command->meta == META_SET)
                        {
                            PgBenchExpr *expr = command->expr;
                            PgBenchValue result;
@@ -2259,7 +2292,7 @@ doCustom(TState *thread, CState *st, StatsData *agg)
                                break;
                            }
                        }
-                       else if (pg_strcasecmp(argv[0], "setshell") == 0)
+                       else if (command->meta == META_SETSHELL)
                        {
                            bool        ret = runShellCommand(st, argv[1], argv + 2, argc - 2);
 
@@ -2279,7 +2312,7 @@ doCustom(TState *thread, CState *st, StatsData *agg)
                                /* succeeded */
                            }
                        }
-                       else if (pg_strcasecmp(argv[0], "shell") == 0)
+                       else if (command->meta == META_SHELL)
                        {
                            bool        ret = runShellCommand(st, NULL, argv + 1, argc - 1);
 
@@ -3023,6 +3056,7 @@ process_sql_command(PQExpBuffer buf, const char *source)
    my_command = (Command *) pg_malloc0(sizeof(Command));
    my_command->command_num = num_commands++;
    my_command->type = SQL_COMMAND;
+   my_command->meta = META_NONE;
    initSimpleStats(&my_command->stats);
 
    /*
@@ -3091,7 +3125,10 @@ process_backslash_command(PsqlScanState sstate, const char *source)
    my_command->argv[j++] = pg_strdup(word_buf.data);
    my_command->argc++;
 
-   if (pg_strcasecmp(my_command->argv[0], "set") == 0)
+   /* ... and convert it to enum form */
+   my_command->meta = getMetaCommand(my_command->argv[0]);
+
+   if (my_command->meta == META_SET)
    {
        /* For \set, collect var name, then lex the expression. */
        yyscan_t    yyscanner;
@@ -3146,7 +3183,7 @@ process_backslash_command(PsqlScanState sstate, const char *source)
                                                  expr_scanner_offset(sstate),
                                                  true);
 
-   if (pg_strcasecmp(my_command->argv[0], "sleep") == 0)
+   if (my_command->meta == META_SLEEP)
    {
        if (my_command->argc < 2)
            syntax_error(source, lineno, my_command->line, my_command->argv[0],
@@ -3187,13 +3224,13 @@ process_backslash_command(PsqlScanState sstate, const char *source)
                             my_command->argv[2], offsets[2] - start_offset);
        }
    }
-   else if (pg_strcasecmp(my_command->argv[0], "setshell") == 0)
+   else if (my_command->meta == META_SETSHELL)
    {
        if (my_command->argc < 3)
            syntax_error(source, lineno, my_command->line, my_command->argv[0],
                         "missing argument", NULL, -1);
    }
-   else if (pg_strcasecmp(my_command->argv[0], "shell") == 0)
+   else if (my_command->meta == META_SHELL)
    {
        if (my_command->argc < 2)
            syntax_error(source, lineno, my_command->line, my_command->argv[0],
@@ -3201,6 +3238,7 @@ process_backslash_command(PsqlScanState sstate, const char *source)
    }
    else
    {
+       /* my_command->meta == META_NONE */
        syntax_error(source, lineno, my_command->line, my_command->argv[0],
                     "invalid command", NULL, -1);
    }
@@ -4592,12 +4630,12 @@ threadRun(void *arg)
                    timeout.tv_usec = min_usec % 1000000;
                    nsocks = select(maxsock + 1, &input_mask, NULL, NULL, &timeout);
                }
-               else /* nothing active, simple sleep */
+               else            /* nothing active, simple sleep */
                {
                    pg_usleep(min_usec);
                }
            }
-           else /* no explicit delay, select without timeout */
+           else                /* no explicit delay, select without timeout */
            {
                nsocks = select(maxsock + 1, &input_mask, NULL, NULL, NULL);
            }
@@ -4614,8 +4652,10 @@ threadRun(void *arg)
                goto done;
            }
        }
-       else /* min_usec == 0, i.e. something needs to be executed */
+       else
        {
+           /* min_usec == 0, i.e. something needs to be executed */
+
            /* If we didn't call select(), don't try to read any data */
            FD_ZERO(&input_mask);
        }