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In the continuing saga of FE/BE protocol revisions, add reporting of

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initial values and runtime changes in selected parameters.  This gets
rid of the need for an initial 'select pg_client_encoding()' query in
libpq, bringing us back to one message transmitted in each direction
for a standard connection startup.  To allow server version to be sent
using the same GUC mechanism that handles other parameters, invent the
concept of a never-settable GUC parameter: you can 'show server_version'
but it's not settable by any GUC input source.  Create 'lc_collate' and
'lc_ctype' never-settable parameters so that people can find out these
settings without need for pg_controldata.  (These side ideas were all
discussed some time ago in pgsql-hackers, but not yet implemented.)
This commit is contained in:
Tom Lane
2003-04-25 19:45:10 +00:00
parent a2190c9eb6
commit 9cbaf72177
13 changed files with 412 additions and 478 deletions
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289
src/interfaces/libpq/fe-connect.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/interfaces/libpq/fe-connect.c,v 1.236 2003/04/25 01:24:00 momjian Exp $
* $Header: /cvsroot/pgsql/src/interfaces/libpq/fe-connect.c,v 1.237 2003/04/25 19:45:09 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -174,8 +174,6 @@ static const struct EnvironmentOptions
static int connectDBStart(PGconn *conn);
static int connectDBComplete(PGconn *conn);
static bool PQsetenvStart(PGconn *conn);
static PostgresPollingStatusType PQsetenvPoll(PGconn *conn);
static PGconn *makeEmptyPGconn(void);
static void freePGconn(PGconn *conn);
static void closePGconn(PGconn *conn);
@ -1207,10 +1205,6 @@ PQconnectPoll(PGconn *conn)
case CONNECTION_MADE:
break;
case CONNECTION_SETENV:
/* We allow PQsetenvPoll to decide whether to proceed */
break;
default:
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext(
@ -1517,10 +1511,10 @@ keep_going: /* We will come back to here until there
* message indicates that startup is successful, but we
* might also get an Error message indicating failure.
* (Notice messages indicating nonfatal warnings are also
* allowed by the protocol, as is a BackendKeyData
* message.) Easiest way to handle this is to let
* PQgetResult() read the messages. We just have to fake
* it out about the state of the connection, by setting
* allowed by the protocol, as are ParameterStatus and
* BackendKeyData messages.) Easiest way to handle this is
* to let PQgetResult() read the messages. We just have to
* fake it out about the state of the connection, by setting
* asyncStatus = PGASYNC_BUSY (done above).
*/
@ -1554,45 +1548,12 @@ keep_going: /* We will come back to here until there
}
/*
* Post-connection housekeeping. Prepare to send
* environment variables to server.
* We are open for business!
*/
if (!PQsetenvStart(conn))
goto error_return;
conn->status = CONNECTION_SETENV;
goto keep_going;
conn->status = CONNECTION_OK;
return PGRES_POLLING_OK;
}
case CONNECTION_SETENV:
/*
* We pretend that the connection is OK for the duration of
* these queries.
*/
conn->status = CONNECTION_OK;
switch (PQsetenvPoll(conn))
{
case PGRES_POLLING_OK: /* Success */
conn->status = CONNECTION_OK;
return PGRES_POLLING_OK;
case PGRES_POLLING_READING: /* Still going */
conn->status = CONNECTION_SETENV;
return PGRES_POLLING_READING;
case PGRES_POLLING_WRITING: /* Still going */
conn->status = CONNECTION_SETENV;
return PGRES_POLLING_WRITING;
default:
conn->status = CONNECTION_SETENV;
goto error_return;
}
/* Unreachable */
default:
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext(
@ -1618,239 +1579,6 @@ error_return:
}
/*
* PQsetenvStart
*
* Starts the process of passing the values of a standard set of environment
* variables to the backend.
*/
static bool
PQsetenvStart(PGconn *conn)
{
if (conn == NULL ||
conn->status == CONNECTION_BAD ||
conn->setenv_state != SETENV_STATE_IDLE)
return false;
conn->setenv_state = SETENV_STATE_ENCODINGS_SEND;
return true;
}
/*
* PQsetenvPoll
*
* Polls the process of passing the values of a standard set of environment
* variables to the backend.
*/
static PostgresPollingStatusType
PQsetenvPoll(PGconn *conn)
{
PGresult *res;
if (conn == NULL || conn->status == CONNECTION_BAD)
return PGRES_POLLING_FAILED;
/* Check whether there are any data for us */
switch (conn->setenv_state)
{
/* These are reading states */
case SETENV_STATE_ENCODINGS_WAIT:
{
/* Load waiting data */
int n = pqReadData(conn);
if (n < 0)
goto error_return;
if (n == 0)
return PGRES_POLLING_READING;
break;
}
/* These are writing states, so we just proceed. */
case SETENV_STATE_ENCODINGS_SEND:
break;
/* Should we raise an error if called when not active? */
case SETENV_STATE_IDLE:
return PGRES_POLLING_OK;
default:
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext(
"invalid setenv state %c, "
"probably indicative of memory corruption\n"
),
conn->setenv_state);
goto error_return;
}
/* We will loop here until there is nothing left to do in this call. */
for (;;)
{
switch (conn->setenv_state)
{
case SETENV_STATE_ENCODINGS_SEND:
{
const char *env = getenv("PGCLIENTENCODING");
if (!env || *env == '\0')
{
/*
* PGCLIENTENCODING is not specified, so query
* server for it. We must use begin/commit in
* case autocommit is off by default.
*/
if (!PQsendQuery(conn, "begin; select pg_client_encoding(); commit"))
goto error_return;
conn->setenv_state = SETENV_STATE_ENCODINGS_WAIT;
return PGRES_POLLING_READING;
}
else
{
/* otherwise set client encoding in pg_conn struct */
int encoding = pg_char_to_encoding(env);
if (encoding < 0)
{
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("invalid encoding name in PGCLIENTENCODING: %s\n"),
env);
goto error_return;
}
conn->client_encoding = encoding;
/* Move on to setting the environment options */
conn->setenv_state = SETENV_STATE_IDLE;
}
break;
}
case SETENV_STATE_ENCODINGS_WAIT:
{
if (PQisBusy(conn))
return PGRES_POLLING_READING;
res = PQgetResult(conn);
if (res)
{
if (PQresultStatus(res) == PGRES_TUPLES_OK)
{
/* set client encoding in pg_conn struct */
char *encoding;
encoding = PQgetvalue(res, 0, 0);
if (!encoding) /* this should not happen */
conn->client_encoding = PG_SQL_ASCII;
else
conn->client_encoding = pg_char_to_encoding(encoding);
}
else if (PQresultStatus(res) != PGRES_COMMAND_OK)
{
PQclear(res);
goto error_return;
}
PQclear(res);
/* Keep reading until PQgetResult returns NULL */
}
else
{
/*
* NULL result indicates that the query is
* finished
*/
conn->setenv_state = SETENV_STATE_IDLE;
}
break;
}
case SETENV_STATE_IDLE:
return PGRES_POLLING_OK;
default:
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("invalid state %c, "
"probably indicative of memory corruption\n"),
conn->setenv_state);
goto error_return;
}
}
/* Unreachable */
error_return:
conn->setenv_state = SETENV_STATE_IDLE;
return PGRES_POLLING_FAILED;
}
#ifdef NOT_USED
/*
* PQsetenv
*
* Passes the values of a standard set of environment variables to the
* backend.
*
* Returns true on success, false on failure.
*
* This function used to be exported for no particularly good reason.
* Since it's no longer used by libpq itself, let's try #ifdef'ing it out
* and see if anyone complains.
*/
static bool
PQsetenv(PGconn *conn)
{
PostgresPollingStatusType flag = PGRES_POLLING_WRITING;
if (!PQsetenvStart(conn))
return false;
for (;;)
{
/*
* Wait, if necessary. Note that the initial state (just after
* PQsetenvStart) is to wait for the socket to select for writing.
*/
switch (flag)
{
case PGRES_POLLING_OK:
return true; /* success! */
case PGRES_POLLING_READING:
if (pqWait(1, 0, conn))
{
conn->status = CONNECTION_BAD;
return false;
}
break;
case PGRES_POLLING_WRITING:
if (pqWait(0, 1, conn))
{
conn->status = CONNECTION_BAD;
return false;
}
break;
default:
/* Just in case we failed to set it in PQsetenvPoll */
conn->status = CONNECTION_BAD;
return false;
}
/*
* Now try to advance the state machine.
*/
flag = PQsetenvPoll(conn);
}
}
#endif /* NOT_USED */
/*
* makeEmptyPGconn
* - create a PGconn data structure with (as yet) no interesting data
@ -1869,7 +1597,6 @@ makeEmptyPGconn(void)
conn->noticeHook = defaultNoticeProcessor;
conn->status = CONNECTION_BAD;
conn->asyncStatus = PGASYNC_IDLE;
conn->setenv_state = SETENV_STATE_IDLE;
conn->notifyList = DLNewList();
conn->sock = -1;
#ifdef USE_SSL