Have SELECT and CREATE TABLE AS queries return a row count. While this

is invisible in psql, other interfaces, like libpq, make this value
visible.

Boszormenyi Zoltan
This commit is contained in:
Bruce Momjian 2010-02-16 20:58:14 +00:00
parent 346a721eed
commit aa7e7ae9a6
4 changed files with 43 additions and 37 deletions

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@ -1,4 +1,4 @@
<!-- $PostgreSQL: pgsql/doc/src/sgml/libpq.sgml,v 1.297 2010/02/05 03:09:04 joe Exp $ -->
<!-- $PostgreSQL: pgsql/doc/src/sgml/libpq.sgml,v 1.298 2010/02/16 20:58:13 momjian Exp $ -->
<chapter id="libpq">
<title><application>libpq</application> - C Library</title>
@ -2869,12 +2869,11 @@ typedef struct {
</sect2>
<sect2 id="libpq-exec-nonselect">
<title>Retrieving Result Information for Other Commands</title>
<title>Retrieving Other Result Information</title>
<para>
These functions are used to extract information from
<structname>PGresult</structname> objects that are not
<command>SELECT</> results.
These functions are used to extract other information from
<structname>PGresult</structname> objects.
</para>
<variablelist>
@ -2925,12 +2924,12 @@ typedef struct {
This function returns a string containing the number of rows
affected by the <acronym>SQL</> statement that generated the
<structname>PGresult</>. This function can only be used following
the execution of an <command>INSERT</>, <command>UPDATE</>,
<command>DELETE</>, <command>MOVE</>, <command>FETCH</>, or
<command>COPY</> statement, or an <command>EXECUTE</> of a
prepared query that contains an <command>INSERT</>,
<command>UPDATE</>, or <command>DELETE</> statement. If the
command that generated the <structname>PGresult</> was anything
the execution of a <command>SELECT</>, <command>CREATE TABLE AS</>,
<command>INSERT</>, <command>UPDATE</>, <command>DELETE</>,
<command>MOVE</>, <command>FETCH</>, or <command>COPY</> statement,
or an <command>EXECUTE</> of a prepared query that contains an
<command>INSERT</>, <command>UPDATE</>, or <command>DELETE</> statement.
If the command that generated the <structname>PGresult</> was anything
else, <function>PQcmdTuples</> returns an empty string. The caller
should not free the return value directly. It will be freed when
the associated <structname>PGresult</> handle is passed to

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@ -1,4 +1,4 @@
<!-- $PostgreSQL: pgsql/doc/src/sgml/protocol.sgml,v 1.79 2010/02/16 20:15:14 momjian Exp $ -->
<!-- $PostgreSQL: pgsql/doc/src/sgml/protocol.sgml,v 1.80 2010/02/16 20:58:14 momjian Exp $ -->
<chapter id="protocol">
<title>Frontend/Backend Protocol</title>
@ -2221,6 +2221,12 @@ CommandComplete (B)
<replaceable>rows</replaceable> is the number of rows updated.
</para>
<para>
For a <command>SELECT</command> or <command>CREATE TABLE AS</command>
command, the tag is <literal>SELECT <replaceable>rows</replaceable></literal>
where <replaceable>rows</replaceable> is the number of rows retrieved.
</para>
<para>
For a <command>MOVE</command> command, the tag is
<literal>MOVE <replaceable>rows</replaceable></literal> where

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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/tcop/pquery.c,v 1.135 2010/02/13 22:45:41 momjian Exp $
* $PostgreSQL: pgsql/src/backend/tcop/pquery.c,v 1.136 2010/02/16 20:58:14 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@ -205,7 +205,8 @@ ProcessQuery(PlannedStmt *plan,
switch (queryDesc->operation)
{
case CMD_SELECT:
strcpy(completionTag, "SELECT");
snprintf(completionTag, COMPLETION_TAG_BUFSIZE,
"SELECT %u", queryDesc->estate->es_processed);
break;
case CMD_INSERT:
if (queryDesc->estate->es_processed == 1)
@ -714,6 +715,7 @@ PortalRun(Portal portal, long count, bool isTopLevel,
char *completionTag)
{
bool result;
uint32 nprocessed;
ResourceOwner saveTopTransactionResourceOwner;
MemoryContext saveTopTransactionContext;
Portal saveActivePortal;
@ -776,39 +778,35 @@ PortalRun(Portal portal, long count, bool isTopLevel,
switch (portal->strategy)
{
case PORTAL_ONE_SELECT:
(void) PortalRunSelect(portal, true, count, dest);
/* we know the query is supposed to set the tag */
if (completionTag && portal->commandTag)
strcpy(completionTag, portal->commandTag);
/* Mark portal not active */
portal->status = PORTAL_READY;
/*
* Since it's a forward fetch, say DONE iff atEnd is now true.
*/
result = portal->atEnd;
break;
case PORTAL_ONE_RETURNING:
case PORTAL_UTIL_SELECT:
/*
* If we have not yet run the command, do so, storing its
* results in the portal's tuplestore.
* results in the portal's tuplestore. Do this only for the
* PORTAL_ONE_RETURNING and PORTAL_UTIL_SELECT cases.
*/
if (!portal->holdStore)
if (portal->strategy != PORTAL_ONE_SELECT && !portal->holdStore)
FillPortalStore(portal, isTopLevel);
/*
* Now fetch desired portion of results.
*/
(void) PortalRunSelect(portal, true, count, dest);
nprocessed = PortalRunSelect(portal, true, count, dest);
/* we know the query is supposed to set the tag */
/*
* If the portal result contains a command tag and the caller
* gave us a pointer to store it, copy it. Patch the "SELECT"
* tag to also provide the rowcount.
*/
if (completionTag && portal->commandTag)
strcpy(completionTag, portal->commandTag);
{
if (strcmp(portal->commandTag, "SELECT") == 0)
snprintf(completionTag, COMPLETION_TAG_BUFSIZE,
"SELECT %u", nprocessed);
else
strcpy(completionTag, portal->commandTag);
}
/* Mark portal not active */
portal->status = PORTAL_READY;
@ -1331,7 +1329,9 @@ PortalRunMulti(Portal portal, bool isTopLevel,
{
if (portal->commandTag)
strcpy(completionTag, portal->commandTag);
if (strcmp(completionTag, "INSERT") == 0)
if (strcmp(completionTag, "SELECT") == 0)
sprintf(completionTag, "SELECT 0 0");
else if (strcmp(completionTag, "INSERT") == 0)
strcpy(completionTag, "INSERT 0 0");
else if (strcmp(completionTag, "UPDATE") == 0)
strcpy(completionTag, "UPDATE 0");

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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/interfaces/libpq/fe-exec.c,v 1.208 2010/01/21 18:43:25 rhaas Exp $
* $PostgreSQL: pgsql/src/interfaces/libpq/fe-exec.c,v 1.209 2010/02/16 20:58:14 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@ -2752,7 +2752,8 @@ PQcmdTuples(PGresult *res)
goto interpret_error; /* no space? */
p++;
}
else if (strncmp(res->cmdStatus, "DELETE ", 7) == 0 ||
else if (strncmp(res->cmdStatus, "SELECT ", 7) == 0 ||
strncmp(res->cmdStatus, "DELETE ", 7) == 0 ||
strncmp(res->cmdStatus, "UPDATE ", 7) == 0)
p = res->cmdStatus + 7;
else if (strncmp(res->cmdStatus, "FETCH ", 6) == 0)