Michaël,
+ bool aset;
It seems to me that there is no point to have the variable aset in
Command because this structure includes already MetaCommand, so the
information is duplicated. [...] Perhaps I am missing something?
Yep. ISTM that you are missing that aset is not an independent meta
command like most others but really changes the state of the previous SQL
command, so that it needs to be stored into that with some additional
fields. This is the same with "gset" which is tagged by a non-null
"varprefix".
So I cannot remove the "aset" field.
And I would suggest to change readCommandResponse() to use a MetaCommand
in argument.
MetaCommand is not enough: we need varprefix, and then distinguishing
between aset and gset. Although this last point can be done with a
MetaCommand, ISTM that a bool is_aset is clear and good enough. It is
possible to switch if you insist on it, but I do not think it is
desirable.
Attached v4 removes an unwanted rebased comment duplication and does minor
changes while re-reading the code.
--
Fabien.
diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index 4c48a58ed2..2c1110c054 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -1026,18 +1026,29 @@ pgbench <optional> <replaceable>options</replaceable> </optional> <replaceable>d
<varlistentry id='pgbench-metacommand-gset'>
<term>
<literal>\gset [<replaceable>prefix</replaceable>]</literal>
+ <literal>\aset [<replaceable>prefix</replaceable>]</literal>
</term>
<listitem>
<para>
- This command may be used to end SQL queries, taking the place of the
+ These commands may be used to end SQL queries, taking the place of the
terminating semicolon (<literal>;</literal>).
</para>
<para>
- When this command is used, the preceding SQL query is expected to
- return one row, the columns of which are stored into variables named after
- column names, and prefixed with <replaceable>prefix</replaceable> if provided.
+ When the <literal>\gset</literal> command is used, the preceding SQL query is
+ expected to return one row, the columns of which are stored into variables
+ named after column names, and prefixed with <replaceable>prefix</replaceable>
+ if provided.
+ </para>
+
+ <para>
+ When the <literal>\aset</literal> command is used, all combined SQL queries
+ (separated by <literal>\;</literal>) have their columns stored into variables
+ named after column names, and prefixed with <replaceable>prefix</replaceable>
+ if provided. If a query returns no row, no assignment is made and the variable
+ can be tested for existence to detect this. If a query returns more than one
+ row, the last value is kept.
</para>
<para>
@@ -1046,6 +1057,8 @@ pgbench <optional> <replaceable>options</replaceable> </optional> <replaceable>d
<replaceable>p_two</replaceable> and <replaceable>p_three</replaceable>
with integers from the third query.
The result of the second query is discarded.
+ The result of the two last combined queries are stored in variables
+ <replaceable>four</replaceable> and <replaceable>five</replaceable>.
<programlisting>
UPDATE pgbench_accounts
SET abalance = abalance + :delta
@@ -1054,6 +1067,7 @@ UPDATE pgbench_accounts
-- compound of two queries
SELECT 1 \;
SELECT 2 AS two, 3 AS three \gset p_
+SELECT 4 AS four \; SELECT 5 AS five \aset
</programlisting>
</para>
</listitem>
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index 4a7ac1f821..da67846814 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -480,6 +480,7 @@ typedef enum MetaCommand
META_SHELL, /* \shell */
META_SLEEP, /* \sleep */
META_GSET, /* \gset */
+ META_ASET, /* \aset */
META_IF, /* \if */
META_ELIF, /* \elif */
META_ELSE, /* \else */
@@ -512,6 +513,7 @@ static const char *QUERYMODE[] = {"simple", "extended", "prepared"};
* varprefix SQL commands terminated with \gset have this set
* to a non NULL value. If nonempty, it's used to prefix the
* variable name that receives the value.
+ * aset do gset on all possible queries of a combined query (\;).
* expr Parsed expression, if needed.
* stats Time spent in this command.
*/
@@ -524,6 +526,7 @@ typedef struct Command
int argc;
char *argv[MAX_ARGS];
char *varprefix;
+ bool aset;
PgBenchExpr *expr;
SimpleStats stats;
} Command;
@@ -2503,6 +2506,8 @@ getMetaCommand(const char *cmd)
mc = META_ENDIF;
else if (pg_strcasecmp(cmd, "gset") == 0)
mc = META_GSET;
+ else if (pg_strcasecmp(cmd, "aset") == 0)
+ mc = META_ASET;
else
mc = META_NONE;
return mc;
@@ -2734,12 +2739,12 @@ sendCommand(CState *st, Command *command)
* Process query response from the backend.
*
* If varprefix is not NULL, it's the variable name prefix where to store
- * the results of the *last* command.
+ * the results of the *last* command (gset) or *all* commands (aset).
*
* Returns true if everything is A-OK, false if any error occurs.
*/
static bool
-readCommandResponse(CState *st, char *varprefix)
+readCommandResponse(CState *st, char *varprefix, bool is_aset)
{
PGresult *res;
PGresult *next_res;
@@ -2759,7 +2764,7 @@ readCommandResponse(CState *st, char *varprefix)
{
case PGRES_COMMAND_OK: /* non-SELECT commands */
case PGRES_EMPTY_QUERY: /* may be used for testing no-op overhead */
- if (is_last && varprefix != NULL)
+ if (is_last && varprefix != NULL && !is_aset)
{
fprintf(stderr,
"client %d script %d command %d query %d: expected one row, got %d\n",
@@ -2769,17 +2774,24 @@ readCommandResponse(CState *st, char *varprefix)
break;
case PGRES_TUPLES_OK:
- if (is_last && varprefix != NULL)
+ if (varprefix != NULL && (is_last || is_aset))
{
- if (PQntuples(res) != 1)
+ int ntuples = PQntuples(res);
+
+ if (!is_aset && ntuples != 1)
{
+ /* under \gset, report the error */
fprintf(stderr,
"client %d script %d command %d query %d: expected one row, got %d\n",
st->id, st->use_file, st->command, qrynum, PQntuples(res));
goto error;
}
- /* store results into variables */
+ /* coldly skip empty result under \aset */
+ if (ntuples <= 0)
+ break;
+
+ /* store results into possibly prefixed variables */
for (int fld = 0; fld < PQnfields(res); fld++)
{
char *varname = PQfname(res, fld);
@@ -2788,15 +2800,14 @@ readCommandResponse(CState *st, char *varprefix)
if (*varprefix != '\0')
varname = psprintf("%s%s", varprefix, varname);
- /* store result as a string */
- if (!putVariable(st, "gset", varname,
- PQgetvalue(res, 0, fld)))
+ /* store last row result as a string */
+ if (!putVariable(st, is_aset ? "aset" : "gset", varname,
+ PQgetvalue(res, ntuples - 1, fld)))
{
/* internal error */
fprintf(stderr,
"client %d script %d command %d query %d: error storing into variable %s\n",
- st->id, st->use_file, st->command, qrynum,
- varname);
+ st->id, st->use_file, st->command, qrynum, varname);
goto error;
}
@@ -2838,7 +2849,7 @@ error:
{
res = PQgetResult(st->con);
PQclear(res);
- } while (res);
+ } while (res != NULL);
return false;
}
@@ -3213,7 +3224,9 @@ advanceConnectionState(TState *thread, CState *st, StatsData *agg)
return; /* don't have the whole result yet */
/* store or discard the query results */
- if (readCommandResponse(st, sql_script[st->use_file].commands[st->command]->varprefix))
+ if (readCommandResponse(st,
+ sql_script[st->use_file].commands[st->command]->varprefix,
+ sql_script[st->use_file].commands[st->command]->aset))
st->state = CSTATE_END_COMMAND;
else
st->state = CSTATE_ABORTED;
@@ -4447,6 +4460,7 @@ create_sql_command(PQExpBuffer buf, const char *source)
my_command->argc = 0;
memset(my_command->argv, 0, sizeof(my_command->argv));
my_command->varprefix = NULL; /* allocated later, if needed */
+ my_command->aset = false;
my_command->expr = NULL;
initSimpleStats(&my_command->stats);
@@ -4675,7 +4689,7 @@ process_backslash_command(PsqlScanState sstate, const char *source)
syntax_error(source, lineno, my_command->first_line, my_command->argv[0],
"unexpected argument", NULL, -1);
}
- else if (my_command->meta == META_GSET)
+ else if (my_command->meta == META_GSET || my_command->meta == META_ASET)
{
if (my_command->argc > 2)
syntax_error(source, lineno, my_command->first_line, my_command->argv[0],
@@ -4820,10 +4834,10 @@ ParseScript(const char *script, const char *desc, int weight)
if (command)
{
/*
- * If this is gset, merge into the preceding command. (We
- * don't use a command slot in this case).
+ * If this is gset or aset, merge into the preceding command.
+ * (We don't use a command slot in this case).
*/
- if (command->meta == META_GSET)
+ if (command->meta == META_GSET || command->meta == META_ASET)
{
Command *cmd;
@@ -4845,6 +4859,7 @@ ParseScript(const char *script, const char *desc, int weight)
cmd->varprefix = pg_strdup("");
else
cmd->varprefix = pg_strdup(command->argv[1]);
+ cmd->aset = (command->meta == META_ASET);
/* cleanup unused command */
free_command(command);
diff --git a/src/bin/pgbench/t/001_pgbench_with_server.pl b/src/bin/pgbench/t/001_pgbench_with_server.pl
index 1845869016..fc286a1af0 100644
--- a/src/bin/pgbench/t/001_pgbench_with_server.pl
+++ b/src/bin/pgbench/t/001_pgbench_with_server.pl
@@ -548,7 +548,7 @@ pgbench(
}
});
-# working \gset
+# working \gset and \aset
pgbench(
'-t 1', 0,
[ qr{type: .*/001_pgbench_gset}, qr{processed: 1/1} ],
@@ -558,9 +558,11 @@ pgbench(
qr{command=6.: int 2\b},
qr{command=8.: int 3\b},
qr{command=10.: int 4\b},
- qr{command=12.: int 5\b}
+ qr{command=12.: int 5\b},
+ qr{command=15.: int 8\b},
+ qr{command=16.: int 7\b}
],
- 'pgbench gset command',
+ 'pgbench gset & aset commands',
{
'001_pgbench_gset' => q{-- test gset
-- no columns
@@ -581,6 +583,12 @@ SELECT 0 AS i4, 4 AS i4 \gset
-- work on the last SQL command under \;
\; \; SELECT 0 AS i5 \; SELECT 5 AS i5 \; \; \gset
\set i debug(:i5)
+-- test aset, which applies to a combined query
+\; SELECT 6 AS i6 \; SELECT 7 AS i7 \; \aset
+-- unless it returns more than one row, last is kept
+SELECT 8 AS i6 UNION SELECT 9 ORDER BY 1 DESC \aset
+\set i debug(:i6)
+\set i debug(:i7)
}
});
