Datum
pg_stat_get_xact_function_self_time(PG_FUNCTION_ARGS)
{
Oid funcid = PG_GETARG_OID(0);
PgStat_BackendFunctionEntry *funcentry;
if ((funcentry = find_funcstat_entry(funcid)) == NULL)
PG_RETURN_NULL();
PG_RETURN_FLOAT8(INSTR_TIME_GET_MILLISEC(funcentry->f_counts.f_self_time));
}
static void process_edge_data(Datum callgraph_buffer_id)
{
int ret;
HASH_SEQ_STATUS hst;
EdgeHashElem *elem;
SPIPlanPtr planptr;
Datum args[7];
Oid argtypes[] = { INT8OID, OIDOID, OIDOID, OIDOID, INT8OID, FLOAT8OID, FLOAT8OID, InvalidOid };
/* Start by freezing the hash table. This saves us some trouble. */
hash_freeze(edge_hash_table);
if ((ret = SPI_connect()) < 0)
elog(ERROR, "could not connect to the SPI: %d", ret);
planptr = SPI_prepare("INSERT INTO "
" call_graph.CallGraphBuffer (CallGraphBufferID, TopLevelFunction, Caller, Callee, "
" Calls, TotalTime, SelfTime) "
" VALUES ($1, $2, $3, $4, $5, $6, $7) ",
7, argtypes);
if (!planptr)
elog(ERROR, "could not prepare an SPI plan for the INSERT into CallGraphBuffer");
args[0] = callgraph_buffer_id;
args[1] = ObjectIdGetDatum(top_level_function_oid);
hash_seq_init(&hst, edge_hash_table);
while ((elem = hash_seq_search(&hst)) != NULL)
{
args[2] = ObjectIdGetDatum(elem->key.caller);
args[3] = ObjectIdGetDatum(elem->key.callee);
args[4] = Int8GetDatum(elem->num_calls);
args[5] = Float8GetDatum(INSTR_TIME_GET_MILLISEC(elem->total_time));
args[6] = Float8GetDatum(INSTR_TIME_GET_MILLISEC(elem->self_time));
if ((ret = SPI_execp(planptr, args, NULL, 0)) < 0)
elog(ERROR, "SPI_execp() failed: %d", ret);
}
SPI_finish();
}
/*
* Like WaitLatch, but with an extra socket argument for WL_SOCKET_*
* conditions.
*
* When waiting on a socket, WL_SOCKET_READABLE *must* be included in
* 'wakeEvents'; WL_SOCKET_WRITEABLE is optional. The reason for this is
* that EOF and error conditions are reported only via WL_SOCKET_READABLE.
*/
int
WaitLatchOrSocket(volatile Latch *latch, int wakeEvents, pgsocket sock,
long timeout)
{
int result = 0;
int rc;
instr_time start_time,
cur_time;
long cur_timeout;
#ifdef HAVE_POLL
struct pollfd pfds[3];
int nfds;
#else
struct timeval tv,
*tvp;
fd_set input_mask;
fd_set output_mask;
int hifd;
#endif
/* Ignore WL_SOCKET_* events if no valid socket is given */
if (sock == PGINVALID_SOCKET)
wakeEvents &= ~(WL_SOCKET_READABLE | WL_SOCKET_WRITEABLE);
Assert(wakeEvents != 0); /* must have at least one wake event */
/* Cannot specify WL_SOCKET_WRITEABLE without WL_SOCKET_READABLE */
Assert((wakeEvents & (WL_SOCKET_READABLE | WL_SOCKET_WRITEABLE)) != WL_SOCKET_WRITEABLE);
if ((wakeEvents & WL_LATCH_SET) && latch->owner_pid != MyProcPid)
elog(ERROR, "cannot wait on a latch owned by another process");
/*
* Initialize timeout if requested. We must record the current time so
* that we can determine the remaining timeout if the poll() or select()
* is interrupted. (On some platforms, select() will update the contents
* of "tv" for us, but unfortunately we can't rely on that.)
*/
if (wakeEvents & WL_TIMEOUT)
{
INSTR_TIME_SET_CURRENT(start_time);
Assert(timeout >= 0 && timeout <= INT_MAX);
cur_timeout = timeout;
#ifndef HAVE_POLL
tv.tv_sec = cur_timeout / 1000L;
tv.tv_usec = (cur_timeout % 1000L) * 1000L;
tvp = &tv;
#endif
}
else
{
cur_timeout = -1;
#ifndef HAVE_POLL
tvp = NULL;
#endif
}
waiting = true;
do
{
/*
* Clear the pipe, then check if the latch is set already. If someone
* sets the latch between this and the poll()/select() below, the
* setter will write a byte to the pipe (or signal us and the signal
* handler will do that), and the poll()/select() will return
* immediately.
*
* Note: we assume that the kernel calls involved in drainSelfPipe()
* and SetLatch() will provide adequate synchronization on machines
* with weak memory ordering, so that we cannot miss seeing is_set if
* the signal byte is already in the pipe when we drain it.
*/
drainSelfPipe();
if ((wakeEvents & WL_LATCH_SET) && latch->is_set)
{
result |= WL_LATCH_SET;
/*
* Leave loop immediately, avoid blocking again. We don't attempt
* to report any other events that might also be satisfied.
*/
break;
}
/* Must wait ... we use poll(2) if available, otherwise select(2) */
#ifdef HAVE_POLL
nfds = 0;
if (wakeEvents & (WL_SOCKET_READABLE | WL_SOCKET_WRITEABLE))
{
/* socket, if used, is always in pfds[0] */
pfds[0].fd = sock;
pfds[0].events = 0;
if (wakeEvents & WL_SOCKET_READABLE)
pfds[0].events |= POLLIN;
if (wakeEvents & WL_SOCKET_WRITEABLE)
pfds[0].events |= POLLOUT;
pfds[0].revents = 0;
nfds++;
}
pfds[nfds].fd = selfpipe_readfd;
pfds[nfds].events = POLLIN;
pfds[nfds].revents = 0;
nfds++;
if (wakeEvents & WL_POSTMASTER_DEATH)
{
/* postmaster fd, if used, is always in pfds[nfds - 1] */
pfds[nfds].fd = postmaster_alive_fds[POSTMASTER_FD_WATCH];
pfds[nfds].events = POLLIN;
pfds[nfds].revents = 0;
nfds++;
}
/* Sleep */
rc = poll(pfds, nfds, (int) cur_timeout);
/* Check return code */
if (rc < 0)
{
/* EINTR is okay, otherwise complain */
if (errno != EINTR)
{
waiting = false;
ereport(ERROR,
(errcode_for_socket_access(),
errmsg("poll() failed: %m")));
}
}
else if (rc == 0)
{
/* timeout exceeded */
if (wakeEvents & WL_TIMEOUT)
result |= WL_TIMEOUT;
}
else
{
/* at least one event occurred, so check revents values */
if ((wakeEvents & WL_SOCKET_READABLE) &&
(pfds[0].revents & (POLLIN | POLLHUP | POLLERR | POLLNVAL)))
{
/* data available in socket, or EOF/error condition */
result |= WL_SOCKET_READABLE;
}
if ((wakeEvents & WL_SOCKET_WRITEABLE) &&
(pfds[0].revents & POLLOUT))
{
result |= WL_SOCKET_WRITEABLE;
}
/*
* We expect a POLLHUP when the remote end is closed, but because
* we don't expect the pipe to become readable or to have any
* errors either, treat those cases as postmaster death, too.
*/
if ((wakeEvents & WL_POSTMASTER_DEATH) &&
(pfds[nfds - 1].revents & (POLLHUP | POLLIN | POLLERR | POLLNVAL)))
{
/*
* According to the select(2) man page on Linux, select(2) may
* spuriously return and report a file descriptor as readable,
* when it's not; and presumably so can poll(2). It's not
* clear that the relevant cases would ever apply to the
* postmaster pipe, but since the consequences of falsely
* returning WL_POSTMASTER_DEATH could be pretty unpleasant,
* we take the trouble to positively verify EOF with
* PostmasterIsAlive().
*/
if (!PostmasterIsAlive())
result |= WL_POSTMASTER_DEATH;
}
}
#else /* !HAVE_POLL */
FD_ZERO(&input_mask);
FD_ZERO(&output_mask);
FD_SET(selfpipe_readfd, &input_mask);
hifd = selfpipe_readfd;
if (wakeEvents & WL_POSTMASTER_DEATH)
{
FD_SET(postmaster_alive_fds[POSTMASTER_FD_WATCH], &input_mask);
if (postmaster_alive_fds[POSTMASTER_FD_WATCH] > hifd)
hifd = postmaster_alive_fds[POSTMASTER_FD_WATCH];
}
if (wakeEvents & WL_SOCKET_READABLE)
{
FD_SET(sock, &input_mask);
if (sock > hifd)
hifd = sock;
}
if (wakeEvents & WL_SOCKET_WRITEABLE)
{
FD_SET(sock, &output_mask);
if (sock > hifd)
hifd = sock;
}
/* Sleep */
rc = select(hifd + 1, &input_mask, &output_mask, NULL, tvp);
/* Check return code */
if (rc < 0)
{
/* EINTR is okay, otherwise complain */
if (errno != EINTR)
{
waiting = false;
ereport(ERROR,
(errcode_for_socket_access(),
errmsg("select() failed: %m")));
}
}
else if (rc == 0)
{
/* timeout exceeded */
if (wakeEvents & WL_TIMEOUT)
result |= WL_TIMEOUT;
}
else
{
/* at least one event occurred, so check masks */
if ((wakeEvents & WL_SOCKET_READABLE) && FD_ISSET(sock, &input_mask))
{
/* data available in socket, or EOF */
result |= WL_SOCKET_READABLE;
}
if ((wakeEvents & WL_SOCKET_WRITEABLE) && FD_ISSET(sock, &output_mask))
{
result |= WL_SOCKET_WRITEABLE;
}
if ((wakeEvents & WL_POSTMASTER_DEATH) &&
FD_ISSET(postmaster_alive_fds[POSTMASTER_FD_WATCH], &input_mask))
{
/*
* According to the select(2) man page on Linux, select(2) may
* spuriously return and report a file descriptor as readable,
* when it's not; and presumably so can poll(2). It's not
* clear that the relevant cases would ever apply to the
* postmaster pipe, but since the consequences of falsely
* returning WL_POSTMASTER_DEATH could be pretty unpleasant,
* we take the trouble to positively verify EOF with
* PostmasterIsAlive().
*/
if (!PostmasterIsAlive())
result |= WL_POSTMASTER_DEATH;
}
}
#endif /* HAVE_POLL */
/* If we're not done, update cur_timeout for next iteration */
if (result == 0 && cur_timeout >= 0)
{
INSTR_TIME_SET_CURRENT(cur_time);
INSTR_TIME_SUBTRACT(cur_time, start_time);
cur_timeout = timeout - (long) INSTR_TIME_GET_MILLISEC(cur_time);
if (cur_timeout < 0)
cur_timeout = 0;
#ifndef HAVE_POLL
tv.tv_sec = cur_timeout / 1000L;
tv.tv_usec = (cur_timeout % 1000L) * 1000L;
#endif
}
} while (result == 0);
waiting = false;
return result;
}
int
WaitLatchOrSocket(volatile Latch *latch, int wakeEvents, pgsocket sock,
long timeout)
{
DWORD rc;
instr_time start_time,
cur_time;
long cur_timeout;
HANDLE events[4];
HANDLE latchevent;
HANDLE sockevent = WSA_INVALID_EVENT;
int numevents;
int result = 0;
int pmdeath_eventno = 0;
/* Ignore WL_SOCKET_* events if no valid socket is given */
if (sock == PGINVALID_SOCKET)
wakeEvents &= ~(WL_SOCKET_READABLE | WL_SOCKET_WRITEABLE);
Assert(wakeEvents != 0); /* must have at least one wake event */
if ((wakeEvents & WL_LATCH_SET) && latch->owner_pid != MyProcPid)
elog(ERROR, "cannot wait on a latch owned by another process");
/*
* Initialize timeout if requested. We must record the current time so
* that we can determine the remaining timeout if WaitForMultipleObjects
* is interrupted.
*/
if (wakeEvents & WL_TIMEOUT)
{
INSTR_TIME_SET_CURRENT(start_time);
Assert(timeout >= 0 && timeout <= INT_MAX);
cur_timeout = timeout;
}
else
cur_timeout = INFINITE;
/*
* Construct an array of event handles for WaitforMultipleObjects().
*
* Note: pgwin32_signal_event should be first to ensure that it will be
* reported when multiple events are set. We want to guarantee that
* pending signals are serviced.
*/
latchevent = latch->event;
events[0] = pgwin32_signal_event;
events[1] = latchevent;
numevents = 2;
if (wakeEvents & (WL_SOCKET_READABLE | WL_SOCKET_WRITEABLE))
{
/* Need an event object to represent events on the socket */
int flags = FD_CLOSE; /* always check for errors/EOF */
if (wakeEvents & WL_SOCKET_READABLE)
flags |= FD_READ;
if (wakeEvents & WL_SOCKET_WRITEABLE)
flags |= FD_WRITE;
sockevent = WSACreateEvent();
if (sockevent == WSA_INVALID_EVENT)
elog(ERROR, "failed to create event for socket: error code %u",
WSAGetLastError());
if (WSAEventSelect(sock, sockevent, flags) != 0)
elog(ERROR, "failed to set up event for socket: error code %u",
WSAGetLastError());
events[numevents++] = sockevent;
}
if (wakeEvents & WL_POSTMASTER_DEATH)
{
pmdeath_eventno = numevents;
events[numevents++] = PostmasterHandle;
}
/* Ensure that signals are serviced even if latch is already set */
pgwin32_dispatch_queued_signals();
do
{
/*
* Reset the event, and check if the latch is set already. If someone
* sets the latch between this and the WaitForMultipleObjects() call
* below, the setter will set the event and WaitForMultipleObjects()
* will return immediately.
*/
if (!ResetEvent(latchevent))
elog(ERROR, "ResetEvent failed: error code %lu", GetLastError());
if ((wakeEvents & WL_LATCH_SET) && latch->is_set)
{
result |= WL_LATCH_SET;
/*
* Leave loop immediately, avoid blocking again. We don't attempt
* to report any other events that might also be satisfied.
*/
break;
}
rc = WaitForMultipleObjects(numevents, events, FALSE, cur_timeout);
if (rc == WAIT_FAILED)
elog(ERROR, "WaitForMultipleObjects() failed: error code %lu",
GetLastError());
else if (rc == WAIT_TIMEOUT)
{
result |= WL_TIMEOUT;
}
else if (rc == WAIT_OBJECT_0)
{
/* Service newly-arrived signals */
pgwin32_dispatch_queued_signals();
}
else if (rc == WAIT_OBJECT_0 + 1)
{
/*
* Latch is set. We'll handle that on next iteration of loop, but
* let's not waste the cycles to update cur_timeout below.
*/
continue;
}
else if ((wakeEvents & (WL_SOCKET_READABLE | WL_SOCKET_WRITEABLE)) &&
rc == WAIT_OBJECT_0 + 2) /* socket is at event slot 2 */
{
WSANETWORKEVENTS resEvents;
ZeroMemory(&resEvents, sizeof(resEvents));
if (WSAEnumNetworkEvents(sock, sockevent, &resEvents) != 0)
elog(ERROR, "failed to enumerate network events: error code %u",
WSAGetLastError());
if ((wakeEvents & WL_SOCKET_READABLE) &&
(resEvents.lNetworkEvents & FD_READ))
{
result |= WL_SOCKET_READABLE;
}
if ((wakeEvents & WL_SOCKET_WRITEABLE) &&
(resEvents.lNetworkEvents & FD_WRITE))
{
result |= WL_SOCKET_WRITEABLE;
}
if (resEvents.lNetworkEvents & FD_CLOSE)
{
if (wakeEvents & WL_SOCKET_READABLE)
result |= WL_SOCKET_READABLE;
if (wakeEvents & WL_SOCKET_WRITEABLE)
result |= WL_SOCKET_WRITEABLE;
}
}
else if ((wakeEvents & WL_POSTMASTER_DEATH) &&
rc == WAIT_OBJECT_0 + pmdeath_eventno)
{
/*
* Postmaster apparently died. Since the consequences of falsely
* returning WL_POSTMASTER_DEATH could be pretty unpleasant, we
* take the trouble to positively verify this with
* PostmasterIsAlive(), even though there is no known reason to
* think that the event could be falsely set on Windows.
*/
if (!PostmasterIsAlive())
result |= WL_POSTMASTER_DEATH;
}
else
elog(ERROR, "unexpected return code from WaitForMultipleObjects(): %lu", rc);
/* If we're not done, update cur_timeout for next iteration */
if (result == 0 && (wakeEvents & WL_TIMEOUT))
{
INSTR_TIME_SET_CURRENT(cur_time);
INSTR_TIME_SUBTRACT(cur_time, start_time);
cur_timeout = timeout - (long) INSTR_TIME_GET_MILLISEC(cur_time);
if (cur_timeout <= 0)
{
/* Timeout has expired, no need to continue looping */
result |= WL_TIMEOUT;
}
}
} while (result == 0);
/* Clean up the event object we created for the socket */
if (sockevent != WSA_INVALID_EVENT)
{
WSAEventSelect(sock, NULL, 0);
WSACloseEvent(sockevent);
}
return result;
}
/*
* Wait for events added to the set to happen, or until the timeout is
* reached. At most nevents occurred events are returned.
*
* If timeout = -1, block until an event occurs; if 0, check sockets for
* readiness, but don't block; if > 0, block for at most timeout miliseconds.
*
* Returns the number of events occurred, or 0 if the timeout was reached.
*
* Returned events will have the fd, pos, user_data fields set to the
* values associated with the registered event.
*/
int
WaitEventSetWait(WaitEventSet *set, long timeout,
WaitEvent *occurred_events, int nevents)
{
int returned_events = 0;
instr_time start_time;
instr_time cur_time;
long cur_timeout = -1;
Assert(nevents > 0);
/*
* Initialize timeout if requested. We must record the current time so
* that we can determine the remaining timeout if interrupted.
*/
if (timeout >= 0)
{
INSTR_TIME_SET_CURRENT(start_time);
Assert(timeout >= 0 && timeout <= INT_MAX);
cur_timeout = timeout;
}
#ifndef WIN32
waiting = true;
#else
/* Ensure that signals are serviced even if latch is already set */
pgwin32_dispatch_queued_signals();
#endif
while (returned_events == 0)
{
int rc;
/*
* Check if the latch is set already. If so, leave the loop
* immediately, avoid blocking again. We don't attempt to report any
* other events that might also be satisfied.
*
* If someone sets the latch between this and the
* WaitEventSetWaitBlock() below, the setter will write a byte to the
* pipe (or signal us and the signal handler will do that), and the
* readiness routine will return immediately.
*
* On unix, If there's a pending byte in the self pipe, we'll notice
* whenever blocking. Only clearing the pipe in that case avoids
* having to drain it every time WaitLatchOrSocket() is used. Should
* the pipe-buffer fill up we're still ok, because the pipe is in
* nonblocking mode. It's unlikely for that to happen, because the
* self pipe isn't filled unless we're blocking (waiting = true), or
* from inside a signal handler in latch_sigusr1_handler().
*
* On windows, we'll also notice if there's a pending event for the
* latch when blocking, but there's no danger of anything filling up,
* as "Setting an event that is already set has no effect.".
*
* Note: we assume that the kernel calls involved in latch management
* will provide adequate synchronization on machines with weak memory
* ordering, so that we cannot miss seeing is_set if a notification
* has already been queued.
*/
if (set->latch && set->latch->is_set)
{
occurred_events->fd = PGINVALID_SOCKET;
occurred_events->pos = set->latch_pos;
occurred_events->user_data =
set->events[set->latch_pos].user_data;
occurred_events->events = WL_LATCH_SET;
occurred_events++;
returned_events++;
break;
}
/*
* Wait for events using the readiness primitive chosen at the top of
* this file. If -1 is returned, a timeout has occurred, if 0 we have
* to retry, everything >= 1 is the number of returned events.
*/
rc = WaitEventSetWaitBlock(set, cur_timeout,
occurred_events, nevents);
if (rc == -1)
break; /* timeout occurred */
else
returned_events = rc;
/* If we're not done, update cur_timeout for next iteration */
if (returned_events == 0 && timeout >= 0)
{
INSTR_TIME_SET_CURRENT(cur_time);
INSTR_TIME_SUBTRACT(cur_time, start_time);
cur_timeout = timeout - (long) INSTR_TIME_GET_MILLISEC(cur_time);
if (cur_timeout <= 0)
break;
}
}
#ifndef WIN32
waiting = false;
#endif
return returned_events;
}
/*
* ExecQueryUsingCursor: run a SELECT-like query using a cursor
*
* This feature allows result sets larger than RAM to be dealt with.
*
* Returns true if the query executed successfully, false otherwise.
*
* If pset.timing is on, total query time (exclusive of result-printing) is
* stored into *elapsed_msec.
*/
static bool
ExecQueryUsingCursor(const char *query, double *elapsed_msec)
{
bool OK = true;
PGresult *results;
PQExpBufferData buf;
printQueryOpt my_popt = pset.popt;
FILE *queryFout_copy = pset.queryFout;
bool queryFoutPipe_copy = pset.queryFoutPipe;
bool started_txn = false;
bool did_pager = false;
int ntuples;
char fetch_cmd[64];
instr_time before,
after;
int flush_error;
*elapsed_msec = 0;
/* initialize print options for partial table output */
my_popt.topt.start_table = true;
my_popt.topt.stop_table = false;
my_popt.topt.prior_records = 0;
if (pset.timing)
INSTR_TIME_SET_CURRENT(before);
/* if we're not in a transaction, start one */
if (PQtransactionStatus(pset.db) == PQTRANS_IDLE)
{
results = PQexec(pset.db, "BEGIN");
OK = AcceptResult(results) &&
(PQresultStatus(results) == PGRES_COMMAND_OK);
PQclear(results);
if (!OK)
return false;
started_txn = true;
}
/* Send DECLARE CURSOR */
initPQExpBuffer(&buf);
appendPQExpBuffer(&buf, "DECLARE _psql_cursor NO SCROLL CURSOR FOR\n%s",
query);
results = PQexec(pset.db, buf.data);
OK = AcceptResult(results) &&
(PQresultStatus(results) == PGRES_COMMAND_OK);
PQclear(results);
termPQExpBuffer(&buf);
if (!OK)
goto cleanup;
if (pset.timing)
{
INSTR_TIME_SET_CURRENT(after);
INSTR_TIME_SUBTRACT(after, before);
*elapsed_msec += INSTR_TIME_GET_MILLISEC(after);
}
snprintf(fetch_cmd, sizeof(fetch_cmd),
"FETCH FORWARD %d FROM _psql_cursor",
pset.fetch_count);
/* prepare to write output to \g argument, if any */
if (pset.gfname)
{
/* keep this code in sync with PrintQueryTuples */
pset.queryFout = stdout; /* so it doesn't get closed */
/* open file/pipe */
if (!setQFout(pset.gfname))
{
pset.queryFout = queryFout_copy;
pset.queryFoutPipe = queryFoutPipe_copy;
OK = false;
goto cleanup;
}
}
/* clear any pre-existing error indication on the output stream */
clearerr(pset.queryFout);
for (;;)
{
if (pset.timing)
INSTR_TIME_SET_CURRENT(before);
/* get FETCH_COUNT tuples at a time */
results = PQexec(pset.db, fetch_cmd);
if (pset.timing)
{
INSTR_TIME_SET_CURRENT(after);
INSTR_TIME_SUBTRACT(after, before);
*elapsed_msec += INSTR_TIME_GET_MILLISEC(after);
}
if (PQresultStatus(results) != PGRES_TUPLES_OK)
{
/* shut down pager before printing error message */
if (did_pager)
{
ClosePager(pset.queryFout);
pset.queryFout = queryFout_copy;
pset.queryFoutPipe = queryFoutPipe_copy;
did_pager = false;
}
OK = AcceptResult(results);
psql_assert(!OK);
PQclear(results);
break;
}
ntuples = PQntuples(results);
if (ntuples < pset.fetch_count)
{
/* this is the last result set, so allow footer decoration */
my_popt.topt.stop_table = true;
}
else if (pset.queryFout == stdout && !did_pager)
{
/*
* If query requires multiple result sets, hack to ensure that
* only one pager instance is used for the whole mess
*/
pset.queryFout = PageOutput(100000, my_popt.topt.pager);
did_pager = true;
}
printQuery(results, &my_popt, pset.queryFout, pset.logfile);
PQclear(results);
/* after the first result set, disallow header decoration */
my_popt.topt.start_table = false;
my_popt.topt.prior_records += ntuples;
/*
* Make sure to flush the output stream, so intermediate results are
* visible to the client immediately. We check the results because if
* the pager dies/exits/etc, there's no sense throwing more data at
* it.
*/
flush_error = fflush(pset.queryFout);
/*
* Check if we are at the end, if a cancel was pressed, or if there
* were any errors either trying to flush out the results, or more
* generally on the output stream at all. If we hit any errors
* writing things to the stream, we presume $PAGER has disappeared and
* stop bothering to pull down more data.
*/
if (ntuples < pset.fetch_count || cancel_pressed || flush_error ||
ferror(pset.queryFout))
break;
}
/* close \g argument file/pipe, restore old setting */
if (pset.gfname)
{
/* keep this code in sync with PrintQueryTuples */
setQFout(NULL);
pset.queryFout = queryFout_copy;
pset.queryFoutPipe = queryFoutPipe_copy;
free(pset.gfname);
pset.gfname = NULL;
}
else if (did_pager)
{
ClosePager(pset.queryFout);
pset.queryFout = queryFout_copy;
pset.queryFoutPipe = queryFoutPipe_copy;
}
cleanup:
if (pset.timing)
INSTR_TIME_SET_CURRENT(before);
/*
* We try to close the cursor on either success or failure, but on failure
* ignore the result (it's probably just a bleat about being in an aborted
* transaction)
*/
results = PQexec(pset.db, "CLOSE _psql_cursor");
if (OK)
{
OK = AcceptResult(results) &&
(PQresultStatus(results) == PGRES_COMMAND_OK);
}
PQclear(results);
if (started_txn)
{
results = PQexec(pset.db, OK ? "COMMIT" : "ROLLBACK");
OK &= AcceptResult(results) &&
(PQresultStatus(results) == PGRES_COMMAND_OK);
PQclear(results);
}
if (pset.timing)
{
INSTR_TIME_SET_CURRENT(after);
INSTR_TIME_SUBTRACT(after, before);
*elapsed_msec += INSTR_TIME_GET_MILLISEC(after);
}
return OK;
}
/*
* SendQuery: send the query string to the backend
* (and print out results)
*
* Note: This is the "front door" way to send a query. That is, use it to
* send queries actually entered by the user. These queries will be subject to
* single step mode.
* To send "back door" queries (generated by slash commands, etc.) in a
* controlled way, use PSQLexec().
*
* Returns true if the query executed successfully, false otherwise.
*/
bool
SendQuery(const char *query)
{
PGresult *results;
PGTransactionStatusType transaction_status;
double elapsed_msec = 0;
bool OK,
on_error_rollback_savepoint = false;
static bool on_error_rollback_warning = false;
if (!pset.db)
{
psql_error("You are currently not connected to a database.\n");
return false;
}
if (pset.singlestep)
{
char buf[3];
printf(_("***(Single step mode: verify command)*******************************************\n"
"%s\n"
"***(press return to proceed or enter x and return to cancel)********************\n"),
query);
fflush(stdout);
if (fgets(buf, sizeof(buf), stdin) != NULL)
if (buf[0] == 'x')
return false;
}
else if (pset.echo == PSQL_ECHO_QUERIES)
{
puts(query);
fflush(stdout);
}
if (pset.logfile)
{
fprintf(pset.logfile,
_("********* QUERY **********\n"
"%s\n"
"**************************\n\n"), query);
fflush(pset.logfile);
}
SetCancelConn();
transaction_status = PQtransactionStatus(pset.db);
if (transaction_status == PQTRANS_IDLE &&
!pset.autocommit &&
!command_no_begin(query))
{
results = PQexec(pset.db, "BEGIN");
if (PQresultStatus(results) != PGRES_COMMAND_OK)
{
psql_error("%s", PQerrorMessage(pset.db));
PQclear(results);
ResetCancelConn();
return false;
}
PQclear(results);
transaction_status = PQtransactionStatus(pset.db);
}
if (transaction_status == PQTRANS_INTRANS &&
pset.on_error_rollback != PSQL_ERROR_ROLLBACK_OFF &&
(pset.cur_cmd_interactive ||
pset.on_error_rollback == PSQL_ERROR_ROLLBACK_ON))
{
if (on_error_rollback_warning == false && pset.sversion < 80000)
{
fprintf(stderr, _("The server (version %d.%d) does not support savepoints for ON_ERROR_ROLLBACK.\n"),
pset.sversion / 10000, (pset.sversion / 100) % 100);
on_error_rollback_warning = true;
}
else
{
results = PQexec(pset.db, "SAVEPOINT pg_psql_temporary_savepoint");
if (PQresultStatus(results) != PGRES_COMMAND_OK)
{
psql_error("%s", PQerrorMessage(pset.db));
PQclear(results);
ResetCancelConn();
return false;
}
PQclear(results);
on_error_rollback_savepoint = true;
}
}
if (pset.fetch_count <= 0 || !is_select_command(query))
{
/* Default fetch-it-all-and-print mode */
instr_time before,
after;
if (pset.timing)
INSTR_TIME_SET_CURRENT(before);
results = PQexec(pset.db, query);
/* these operations are included in the timing result: */
ResetCancelConn();
OK = (AcceptResult(results) && ProcessCopyResult(results));
if (pset.timing)
{
INSTR_TIME_SET_CURRENT(after);
INSTR_TIME_SUBTRACT(after, before);
elapsed_msec = INSTR_TIME_GET_MILLISEC(after);
}
/* but printing results isn't: */
if (OK)
OK = PrintQueryResults(results);
}
else
{
/* Fetch-in-segments mode */
OK = ExecQueryUsingCursor(query, &elapsed_msec);
ResetCancelConn();
results = NULL; /* PQclear(NULL) does nothing */
}
/* If we made a temporary savepoint, possibly release/rollback */
if (on_error_rollback_savepoint)
{
const char *svptcmd;
transaction_status = PQtransactionStatus(pset.db);
if (transaction_status == PQTRANS_INERROR)
{
/* We always rollback on an error */
svptcmd = "ROLLBACK TO pg_psql_temporary_savepoint";
}
else if (transaction_status != PQTRANS_INTRANS)
{
/* If they are no longer in a transaction, then do nothing */
svptcmd = NULL;
}
else
{
/*
* Do nothing if they are messing with savepoints themselves: If
* the user did RELEASE or ROLLBACK, our savepoint is gone. If
* they issued a SAVEPOINT, releasing ours would remove theirs.
*/
if (results &&
(strcmp(PQcmdStatus(results), "SAVEPOINT") == 0 ||
strcmp(PQcmdStatus(results), "RELEASE") == 0 ||
strcmp(PQcmdStatus(results), "ROLLBACK") == 0))
svptcmd = NULL;
else
svptcmd = "RELEASE pg_psql_temporary_savepoint";
}
if (svptcmd)
{
PGresult *svptres;
svptres = PQexec(pset.db, svptcmd);
if (PQresultStatus(svptres) != PGRES_COMMAND_OK)
{
psql_error("%s", PQerrorMessage(pset.db));
PQclear(svptres);
PQclear(results);
ResetCancelConn();
return false;
}
PQclear(svptres);
}
}
PQclear(results);
/* Possible microtiming output */
if (OK && pset.timing)
printf(_("Time: %.3f ms\n"), elapsed_msec);
/* check for events that may occur during query execution */
if (pset.encoding != PQclientEncoding(pset.db) &&
PQclientEncoding(pset.db) >= 0)
{
/* track effects of SET CLIENT_ENCODING */
pset.encoding = PQclientEncoding(pset.db);
pset.popt.topt.encoding = pset.encoding;
SetVariable(pset.vars, "ENCODING",
pg_encoding_to_char(pset.encoding));
}
PrintNotifications();
return OK;
}
/*
* Subroutine to actually try to execute a backslash command.
*/
static backslashResult
exec_command(const char *cmd,
PsqlScanState scan_state,
PQExpBuffer query_buf)
{
bool success = true; /* indicate here if the command ran ok or
* failed */
backslashResult status = PSQL_CMD_SKIP_LINE;
/*
* \a -- toggle field alignment This makes little sense but we keep it
* around.
*/
if (strcmp(cmd, "a") == 0)
{
if (pset.popt.topt.format != PRINT_ALIGNED)
success = do_pset("format", "aligned", &pset.popt, pset.quiet);
else
success = do_pset("format", "unaligned", &pset.popt, pset.quiet);
}
/* \C -- override table title (formerly change HTML caption) */
else if (strcmp(cmd, "C") == 0)
{
char *opt = psql_scan_slash_option(scan_state,
OT_NORMAL, NULL, true);
success = do_pset("title", opt, &pset.popt, pset.quiet);
free(opt);
}
/*
* \c or \connect -- connect to database using the specified parameters.
*
* \c dbname user host port
*
* If any of these parameters are omitted or specified as '-', the current
* value of the parameter will be used instead. If the parameter has no
* current value, the default value for that parameter will be used. Some
* examples:
*
* \c - - hst Connect to current database on current port of host
* "hst" as current user. \c - usr - prt Connect to current database on
* "prt" port of current host as user "usr". \c dbs Connect to
* "dbs" database on current port of current host as current user.
*/
else if (strcmp(cmd, "c") == 0 || strcmp(cmd, "connect") == 0)
{
char *opt1,
*opt2,
*opt3,
*opt4;
opt1 = read_connect_arg(scan_state);
opt2 = read_connect_arg(scan_state);
opt3 = read_connect_arg(scan_state);
opt4 = read_connect_arg(scan_state);
success = do_connect(opt1, opt2, opt3, opt4);
free(opt1);
free(opt2);
free(opt3);
free(opt4);
}
/* \cd */
else if (strcmp(cmd, "cd") == 0)
{
char *opt = psql_scan_slash_option(scan_state,
OT_NORMAL, NULL, true);
char *dir;
if (opt)
dir = opt;
else
{
#ifndef WIN32
struct passwd *pw;
pw = getpwuid(geteuid());
if (!pw)
{
psql_error("could not get home directory: %s\n", strerror(errno));
exit(EXIT_FAILURE);
}
dir = pw->pw_dir;
#else /* WIN32 */
/*
* On Windows, 'cd' without arguments prints the current
* directory, so if someone wants to code this here instead...
*/
dir = "/";
#endif /* WIN32 */
}
if (chdir(dir) == -1)
{
psql_error("\\%s: could not change directory to \"%s\": %s\n",
cmd, dir, strerror(errno));
success = false;
}
if (pset.dirname)
free(pset.dirname);
pset.dirname = pg_strdup(dir);
canonicalize_path(pset.dirname);
if (opt)
free(opt);
}
/* \conninfo -- display information about the current connection */
else if (strcmp(cmd, "conninfo") == 0)
{
char *db = PQdb(pset.db);
char *host = PQhost(pset.db);
if (db == NULL)
printf(_("You are not connected.\n"));
else
{
if (host == NULL)
host = DEFAULT_PGSOCKET_DIR;
/* If the host is an absolute path, the connection is via socket */
if (is_absolute_path(host))
printf(_("You are connected to database \"%s\" as user \"%s\" via socket in \"%s\" at port \"%s\".\n"),
db, PQuser(pset.db), host, PQport(pset.db));
else
printf(_("You are connected to database \"%s\" as user \"%s\" on host \"%s\" at port \"%s\".\n"),
db, PQuser(pset.db), host, PQport(pset.db));
}
}
/* \copy */
else if (pg_strcasecmp(cmd, "copy") == 0)
{
/* Default fetch-it-all-and-print mode */
instr_time before,
after;
char *opt = psql_scan_slash_option(scan_state,
OT_WHOLE_LINE, NULL, false);
if (pset.timing)
INSTR_TIME_SET_CURRENT(before);
success = do_copy(opt);
if (pset.timing && success)
{
INSTR_TIME_SET_CURRENT(after);
INSTR_TIME_SUBTRACT(after, before);
printf(_("Time: %.3f ms\n"), INSTR_TIME_GET_MILLISEC(after));
}
free(opt);
}
/* \copyright */
else if (strcmp(cmd, "copyright") == 0)
print_copyright();
/* \d* commands */
else if (cmd[0] == 'd')
{
char *pattern;
bool show_verbose,
show_system;
/* We don't do SQLID reduction on the pattern yet */
pattern = psql_scan_slash_option(scan_state,
OT_NORMAL, NULL, true);
show_verbose = strchr(cmd, '+') ? true : false;
show_system = strchr(cmd, 'S') ? true : false;
switch (cmd[1])
{
case '\0':
case '+':
case 'S': /* GPDB: This is a change from old behavior: We used to show just system tables */
if (pattern)
success = describeTableDetails(pattern, show_verbose, show_system);
else
/* standard listing of interesting things */
success = listTables("tvsxr", NULL, show_verbose, show_system);
break;
case 'a':
success = describeAggregates(pattern, show_verbose, show_system);
break;
case 'b':
success = describeTablespaces(pattern, show_verbose);
break;
case 'c':
success = listConversions(pattern, show_system);
break;
case 'C':
success = listCasts(pattern);
break;
case 'd':
if (strncmp(cmd, "ddp", 3) == 0)
success = listDefaultACLs(pattern);
else
success = objectDescription(pattern, show_system);
break;
case 'D':
success = listDomains(pattern, show_system);
break;
case 'f': /* function subsystem */
switch (cmd[2])
{
case '\0':
case '+':
case 'S':
case 'a':
case 'n':
case 't':
case 'w':
success = describeFunctions(&cmd[2], pattern, show_verbose, show_system);
break;
default:
status = PSQL_CMD_UNKNOWN;
break;
}
break;
case 'g':
/* no longer distinct from \du */
success = describeRoles(pattern, show_verbose);
break;
case 'l':
success = do_lo_list();
break;
case 'n':
success = listSchemas(pattern, show_verbose);
break;
case 'o':
success = describeOperators(pattern, show_system);
break;
case 'p':
success = permissionsList(pattern);
break;
case 'T':
success = describeTypes(pattern, show_verbose, show_system);
break;
case 't':
case 'v':
case 'i':
case 's':
case 'E': /* PostgreSQL use dx for extension, change to dE for foreign table */
/* case 'S': // GPDB: We used to show just system tables for this */
case 'P': /* GPDB: Parent-only tables, no children */
success = listTables(&cmd[1], pattern, show_verbose, show_system);
break;
case 'r':
if (cmd[2] == 'd' && cmd[3] == 's')
{
char *pattern2 = NULL;
if (pattern)
pattern2 = psql_scan_slash_option(scan_state,
OT_NORMAL, NULL, true);
success = listDbRoleSettings(pattern, pattern2);
}
else
//success = PSQL_CMD_UNKNOWN;
/* GPDB uses \dr for foreign tables ? */
success = listTables(&cmd[1], pattern, show_verbose, show_system);
break;
case 'u':
success = describeRoles(pattern, show_verbose);
break;
case 'F': /* text search subsystem */
switch (cmd[2])
{
case '\0':
case '+':
success = listTSConfigs(pattern, show_verbose);
break;
case 'p':
success = listTSParsers(pattern, show_verbose);
break;
case 'd':
success = listTSDictionaries(pattern, show_verbose);
break;
case 't':
success = listTSTemplates(pattern, show_verbose);
break;
default:
status = PSQL_CMD_UNKNOWN;
break;
}
break;
case 'x': /* Extensions */
if (show_verbose)
success = listExtensionContents(pattern);
else
success = listExtensions(pattern);
break;
default:
status = PSQL_CMD_UNKNOWN;
}
if (pattern)
free(pattern);
}
/*
* \e or \edit -- edit the current query buffer, or edit a file and make
* it the query buffer
*/
else if (strcmp(cmd, "e") == 0 || strcmp(cmd, "edit") == 0)
{
if (!query_buf)
{
psql_error("no query buffer\n");
status = PSQL_CMD_ERROR;
}
else
{
char *fname;
fname = psql_scan_slash_option(scan_state,
OT_NORMAL, NULL, true);
expand_tilde(&fname);
if (fname)
canonicalize_path(fname);
if (do_edit(fname, query_buf, NULL))
status = PSQL_CMD_NEWEDIT;
else
status = PSQL_CMD_ERROR;
free(fname);
}
}
/*
* \ef -- edit the named function, or present a blank CREATE FUNCTION
* template if no argument is given
*/
else if (strcmp(cmd, "ef") == 0)
{
if (!query_buf)
{
psql_error("no query buffer\n");
status = PSQL_CMD_ERROR;
}
else
{
char *func;
Oid foid = InvalidOid;
func = psql_scan_slash_option(scan_state,
OT_WHOLE_LINE, NULL, true);
if (!func)
{
/* set up an empty command to fill in */
printfPQExpBuffer(query_buf,
"CREATE FUNCTION ( )\n"
" RETURNS \n"
" LANGUAGE \n"
" -- common options: IMMUTABLE STABLE STRICT SECURITY DEFINER\n"
"AS $function$\n"
"\n$function$\n");
}
else if (!lookup_function_oid(pset.db, func, &foid))
{
/* error already reported */
status = PSQL_CMD_ERROR;
}
else if (!get_create_function_cmd(pset.db, foid, query_buf))
{
/* error already reported */
status = PSQL_CMD_ERROR;
}
if (func)
free(func);
}
if (status != PSQL_CMD_ERROR)
{
bool edited = false;
if (!do_edit(0, query_buf, &edited))
status = PSQL_CMD_ERROR;
else if (!edited)
puts(_("No changes"));
else
status = PSQL_CMD_NEWEDIT;
}
}
/* \echo and \qecho */
else if (strcmp(cmd, "echo") == 0 || strcmp(cmd, "qecho") == 0)
{
char *value;
char quoted;
bool no_newline = false;
bool first = true;
FILE *fout;
if (strcmp(cmd, "qecho") == 0)
fout = pset.queryFout;
else
fout = stdout;
while ((value = psql_scan_slash_option(scan_state,
OT_NORMAL, "ed, false)))
{
if (!quoted && strcmp(value, "-n") == 0)
no_newline = true;
else
{
if (first)
first = false;
else
fputc(' ', fout);
fputs(value, fout);
}
free(value);
}
if (!no_newline)
fputs("\n", fout);
}
/* \encoding -- set/show client side encoding */
else if (strcmp(cmd, "encoding") == 0)
{
char *encoding = psql_scan_slash_option(scan_state,
OT_NORMAL, NULL, false);
if (!encoding)
{
/* show encoding */
puts(pg_encoding_to_char(pset.encoding));
}
else
{
/* set encoding */
if (PQsetClientEncoding(pset.db, encoding) == -1)
psql_error("%s: invalid encoding name or conversion procedure not found\n", encoding);
else
{
/* save encoding info into psql internal data */
pset.encoding = PQclientEncoding(pset.db);
pset.popt.topt.encoding = pset.encoding;
SetVariable(pset.vars, "ENCODING",
pg_encoding_to_char(pset.encoding));
}
free(encoding);
}
}
/* \f -- change field separator */
else if (strcmp(cmd, "f") == 0)
{
char *fname = psql_scan_slash_option(scan_state,
OT_NORMAL, NULL, false);
success = do_pset("fieldsep", fname, &pset.popt, pset.quiet);
free(fname);
}
/* \g means send query */
else if (strcmp(cmd, "g") == 0)
{
char *fname = psql_scan_slash_option(scan_state,
OT_FILEPIPE, NULL, false);
if (!fname)
pset.gfname = NULL;
else
{
expand_tilde(&fname);
pset.gfname = pg_strdup(fname);
}
free(fname);
status = PSQL_CMD_SEND;
}
/* help */
else if (strcmp(cmd, "h") == 0 || strcmp(cmd, "help") == 0)
{
char *opt = psql_scan_slash_option(scan_state,
OT_WHOLE_LINE, NULL, false);
size_t len;
/* strip any trailing spaces and semicolons */
if (opt)
{
len = strlen(opt);
while (len > 0 &&
(isspace((unsigned char) opt[len - 1])
|| opt[len - 1] == ';'))
opt[--len] = '\0';
}
helpSQL(opt, pset.popt.topt.pager);
free(opt);
}
/* HTML mode */
else if (strcmp(cmd, "H") == 0 || strcmp(cmd, "html") == 0)
{
if (pset.popt.topt.format != PRINT_HTML)
success = do_pset("format", "html", &pset.popt, pset.quiet);
else
success = do_pset("format", "aligned", &pset.popt, pset.quiet);
}
/* \i is include file */
else if (strcmp(cmd, "i") == 0 || strcmp(cmd, "include") == 0)
{
char *fname = psql_scan_slash_option(scan_state,
OT_NORMAL, NULL, true);
if (!fname)
{
psql_error("\\%s: missing required argument\n", cmd);
success = false;
}
else
{
expand_tilde(&fname);
success = (process_file(fname, false) == EXIT_SUCCESS);
free(fname);
}
}
/* \l is list databases */
else if (strcmp(cmd, "l") == 0 || strcmp(cmd, "list") == 0)
success = listAllDbs(false);
else if (strcmp(cmd, "l+") == 0 || strcmp(cmd, "list+") == 0)
success = listAllDbs(true);
/*
* large object things
*/
else if (strncmp(cmd, "lo_", 3) == 0)
{
char *opt1,
*opt2;
opt1 = psql_scan_slash_option(scan_state,
OT_NORMAL, NULL, true);
opt2 = psql_scan_slash_option(scan_state,
OT_NORMAL, NULL, true);
if (strcmp(cmd + 3, "export") == 0)
{
if (!opt2)
{
psql_error("\\%s: missing required argument\n", cmd);
success = false;
}
else
{
expand_tilde(&opt2);
success = do_lo_export(opt1, opt2);
}
}
else if (strcmp(cmd + 3, "import") == 0)
{
if (!opt1)
{
psql_error("\\%s: missing required argument\n", cmd);
success = false;
}
else
{
expand_tilde(&opt1);
success = do_lo_import(opt1, opt2);
}
}
else if (strcmp(cmd + 3, "list") == 0)
success = do_lo_list();
else if (strcmp(cmd + 3, "unlink") == 0)
{
if (!opt1)
{
psql_error("\\%s: missing required argument\n", cmd);
success = false;
}
else
success = do_lo_unlink(opt1);
}
else
status = PSQL_CMD_UNKNOWN;
free(opt1);
free(opt2);
}
/* \o -- set query output */
else if (strcmp(cmd, "o") == 0 || strcmp(cmd, "out") == 0)
{
char *fname = psql_scan_slash_option(scan_state,
OT_FILEPIPE, NULL, true);
expand_tilde(&fname);
success = setQFout(fname);
free(fname);
}
/* \p prints the current query buffer */
else if (strcmp(cmd, "p") == 0 || strcmp(cmd, "print") == 0)
{
if (query_buf && query_buf->len > 0)
puts(query_buf->data);
else if (!pset.quiet)
puts(_("Query buffer is empty."));
fflush(stdout);
}
/* \password -- set user password */
else if (strcmp(cmd, "password") == 0)
{
char *pw1;
char *pw2;
pw1 = simple_prompt("Enter new password: "******"Enter it again: ", 100, false);
if (strcmp(pw1, pw2) != 0)
{
fprintf(stderr, _("Passwords didn't match.\n"));
success = false;
}
else
{
char *opt0 = psql_scan_slash_option(scan_state, OT_SQLID, NULL, true);
char *user;
char *encrypted_password;
if (opt0)
user = opt0;
else
user = PQuser(pset.db);
encrypted_password = PQencryptPassword(pw1, user);
if (!encrypted_password)
{
fprintf(stderr, _("Password encryption failed.\n"));
success = false;
}
else
{
PQExpBufferData buf;
PGresult *res;
initPQExpBuffer(&buf);
printfPQExpBuffer(&buf, "ALTER USER %s PASSWORD ",
fmtId(user));
appendStringLiteralConn(&buf, encrypted_password, pset.db);
res = PSQLexec(buf.data, false);
termPQExpBuffer(&buf);
if (!res)
success = false;
else
PQclear(res);
PQfreemem(encrypted_password);
}
}
free(pw1);
free(pw2);
}
/* \prompt -- prompt and set variable */
else if (strcmp(cmd, "prompt") == 0)
{
char *opt,
*prompt_text = NULL;
char *arg1,
*arg2;
arg1 = psql_scan_slash_option(scan_state, OT_NORMAL, NULL, false);
arg2 = psql_scan_slash_option(scan_state, OT_NORMAL, NULL, false);
if (!arg1)
{
psql_error("\\%s: missing required argument\n", cmd);
success = false;
}
else
{
char *result;
if (arg2)
{
prompt_text = arg1;
opt = arg2;
}
else
opt = arg1;
if (!pset.inputfile)
result = simple_prompt(prompt_text, 4096, true);
else
{
if (prompt_text)
{
fputs(prompt_text, stdout);
fflush(stdout);
}
result = gets_fromFile(stdin);
}
if (!SetVariable(pset.vars, opt, result))
{
psql_error("\\%s: error\n", cmd);
success = false;
}
free(result);
if (prompt_text)
free(prompt_text);
free(opt);
}
}
/* \pset -- set printing parameters */
else if (strcmp(cmd, "pset") == 0)
{
char *opt0 = psql_scan_slash_option(scan_state,
OT_NORMAL, NULL, false);
char *opt1 = psql_scan_slash_option(scan_state,
OT_NORMAL, NULL, false);
if (!opt0)
{
psql_error("\\%s: missing required argument\n", cmd);
success = false;
}
else
success = do_pset(opt0, opt1, &pset.popt, pset.quiet);
free(opt0);
free(opt1);
}
/* \q or \quit */
else if (strcmp(cmd, "q") == 0 || strcmp(cmd, "quit") == 0)
status = PSQL_CMD_TERMINATE;
/* reset(clear) the buffer */
else if (strcmp(cmd, "r") == 0 || strcmp(cmd, "reset") == 0)
{
resetPQExpBuffer(query_buf);
psql_scan_reset(scan_state);
if (!pset.quiet)
puts(_("Query buffer reset (cleared)."));
}
/* \s save history in a file or show it on the screen */
else if (strcmp(cmd, "s") == 0)
{
char *fname = psql_scan_slash_option(scan_state,
OT_NORMAL, NULL, true);
#if defined(WIN32) && !defined(__CYGWIN__)
/*
* XXX This does not work for all terminal environments or for output
* containing non-ASCII characters; see comments in simple_prompt().
*/
#define DEVTTY "con"
#else
#define DEVTTY "/dev/tty"
#endif
expand_tilde(&fname);
/* This scrolls off the screen when using /dev/tty */
success = saveHistory(fname ? fname : DEVTTY, -1, false, false);
if (success && !pset.quiet && fname)
printf(gettext("Wrote history to file \"%s/%s\".\n"),
pset.dirname ? pset.dirname : ".", fname);
if (!fname)
putchar('\n');
free(fname);
}
/* \set -- generalized set variable/option command */
else if (strcmp(cmd, "set") == 0)
{
char *opt0 = psql_scan_slash_option(scan_state,
OT_NORMAL, NULL, false);
if (!opt0)
{
/* list all variables */
PrintVariables(pset.vars);
success = true;
}
else
{
/*
* Set variable to the concatenation of the arguments.
*/
char *newval;
char *opt;
opt = psql_scan_slash_option(scan_state,
OT_NORMAL, NULL, false);
newval = pg_strdup(opt ? opt : "");
free(opt);
while ((opt = psql_scan_slash_option(scan_state,
OT_NORMAL, NULL, false)))
{
newval = realloc(newval, strlen(newval) + strlen(opt) + 1);
if (!newval)
{
psql_error("out of memory\n");
exit(EXIT_FAILURE);
}
strcat(newval, opt);
free(opt);
}
if (!SetVariable(pset.vars, opt0, newval))
{
psql_error("\\%s: error\n", cmd);
success = false;
}
free(newval);
}
free(opt0);
}
/* \t -- turn off headers and row count */
else if (strcmp(cmd, "t") == 0)
{
char *opt = psql_scan_slash_option(scan_state,
OT_NORMAL, NULL, true);
success = do_pset("tuples_only", opt, &pset.popt, pset.quiet);
free(opt);
}
/* \T -- define html <table ...> attributes */
else if (strcmp(cmd, "T") == 0)
{
char *value = psql_scan_slash_option(scan_state,
OT_NORMAL, NULL, false);
success = do_pset("tableattr", value, &pset.popt, pset.quiet);
free(value);
}
/* \timing -- toggle timing of queries */
else if (strcmp(cmd, "timing") == 0)
{
char *opt = psql_scan_slash_option(scan_state,
OT_NORMAL, NULL, false);
if (opt)
pset.timing = ParseVariableBool(opt);
else
pset.timing = !pset.timing;
if (!pset.quiet)
{
if (pset.timing)
puts(_("Timing is on."));
else
puts(_("Timing is off."));
}
free(opt);
}
/* \unset */
else if (strcmp(cmd, "unset") == 0)
{
char *opt = psql_scan_slash_option(scan_state,
OT_NORMAL, NULL, false);
if (!opt)
{
psql_error("\\%s: missing required argument\n", cmd);
success = false;
}
else if (!SetVariable(pset.vars, opt, NULL))
{
psql_error("\\%s: error\n", cmd);
success = false;
}
free(opt);
}
/* \w -- write query buffer to file */
else if (strcmp(cmd, "w") == 0 || strcmp(cmd, "write") == 0)
{
FILE *fd = NULL;
bool is_pipe = false;
char *fname = NULL;
if (!query_buf)
{
psql_error("no query buffer\n");
status = PSQL_CMD_ERROR;
}
else
{
fname = psql_scan_slash_option(scan_state,
OT_FILEPIPE, NULL, true);
expand_tilde(&fname);
if (!fname)
{
psql_error("\\%s: missing required argument\n", cmd);
success = false;
}
else
{
if (fname[0] == '|')
{
is_pipe = true;
fd = popen(&fname[1], "w");
}
else
{
canonicalize_path(fname);
fd = fopen(fname, "w");
}
if (!fd)
{
psql_error("%s: %s\n", fname, strerror(errno));
success = false;
}
}
}
if (fd)
{
int result;
if (query_buf && query_buf->len > 0)
fprintf(fd, "%s\n", query_buf->data);
if (is_pipe)
result = pclose(fd);
else
result = fclose(fd);
if (result == EOF)
{
psql_error("%s: %s\n", fname, strerror(errno));
success = false;
}
}
free(fname);
}
/* \x -- toggle expanded table representation */
else if (strcmp(cmd, "x") == 0)
{
char *opt = psql_scan_slash_option(scan_state,
OT_NORMAL, NULL, true);
success = do_pset("expanded", opt, &pset.popt, pset.quiet);
free(opt);
}
/* \z -- list table rights (equivalent to \dp) */
else if (strcmp(cmd, "z") == 0)
{
char *pattern = psql_scan_slash_option(scan_state,
OT_NORMAL, NULL, true);
success = permissionsList(pattern);
if (pattern)
free(pattern);
}
/* \! -- shell escape */
else if (strcmp(cmd, "!") == 0)
{
char *opt = psql_scan_slash_option(scan_state,
OT_WHOLE_LINE, NULL, false);
success = do_shell(opt);
free(opt);
}
/* \? -- slash command help */
else if (strcmp(cmd, "?") == 0)
slashUsage(pset.popt.topt.pager);
#if 0
/*
* These commands don't do anything. I just use them to test the parser.
*/
else if (strcmp(cmd, "void") == 0 || strcmp(cmd, "#") == 0)
{
int i = 0;
char *value;
while ((value = psql_scan_slash_option(scan_state,
OT_NORMAL, NULL, true)))
{
fprintf(stderr, "+ opt(%d) = |%s|\n", i++, value);
free(value);
}
}
#endif
else
status = PSQL_CMD_UNKNOWN;
if (!success)
status = PSQL_CMD_ERROR;
return status;
}
/*
* PSQLexecWatch
*
* This function is used for \watch command to send the query to
* the server and print out the results.
*
* Returns 1 if the query executed successfully, 0 if it cannot be repeated,
* e.g., because of the interrupt, -1 on error.
*/
int
PSQLexecWatch(const char *query, const printQueryOpt *opt)
{
PGresult *res;
double elapsed_msec = 0;
instr_time before;
instr_time after;
if (!pset.db)
{
psql_error("You are currently not connected to a database.\n");
return 0;
}
SetCancelConn();
if (pset.timing)
INSTR_TIME_SET_CURRENT(before);
res = PQexec(pset.db, query);
ResetCancelConn();
if (!AcceptResult(res))
{
PQclear(res);
return 0;
}
if (pset.timing)
{
INSTR_TIME_SET_CURRENT(after);
INSTR_TIME_SUBTRACT(after, before);
elapsed_msec = INSTR_TIME_GET_MILLISEC(after);
}
/*
* If SIGINT is sent while the query is processing, the interrupt
* will be consumed. The user's intention, though, is to cancel
* the entire watch process, so detect a sent cancellation request and
* exit in this case.
*/
if (cancel_pressed)
{
PQclear(res);
return 0;
}
switch (PQresultStatus(res))
{
case PGRES_TUPLES_OK:
printQuery(res, opt, pset.queryFout, pset.logfile);
break;
case PGRES_COMMAND_OK:
fprintf(pset.queryFout, "%s\n%s\n\n", opt->title, PQcmdStatus(res));
break;
case PGRES_EMPTY_QUERY:
psql_error(_("\\watch cannot be used with an empty query\n"));
PQclear(res);
return -1;
case PGRES_COPY_OUT:
case PGRES_COPY_IN:
case PGRES_COPY_BOTH:
psql_error(_("\\watch cannot be used with COPY\n"));
PQclear(res);
return -1;
default:
psql_error(_("unexpected result status for \\watch\n"));
PQclear(res);
return -1;
}
PQclear(res);
fflush(pset.queryFout);
/* Possible microtiming output */
if (pset.timing)
printf(_("Time: %.3f ms\n"), elapsed_msec);
return 1;
}
/*
* ExecQueryUsingCursor: run a SELECT-like query using a cursor
*
* This feature allows result sets larger than RAM to be dealt with.
*
* Returns true if the query executed successfully, false otherwise.
*
* If pset.timing is on, total query time (exclusive of result-printing) is
* stored into *elapsed_msec.
*/
static bool
ExecQueryUsingCursor(const char *query, double *elapsed_msec)
{
bool OK = true;
PGresult *results;
PQExpBufferData buf;
printQueryOpt my_popt = pset.popt;
FILE *fout;
bool is_pipe;
bool is_pager = false;
bool started_txn = false;
int ntuples;
int fetch_count;
char fetch_cmd[64];
instr_time before,
after;
int flush_error;
*elapsed_msec = 0;
/* initialize print options for partial table output */
my_popt.topt.start_table = true;
my_popt.topt.stop_table = false;
my_popt.topt.prior_records = 0;
if (pset.timing)
INSTR_TIME_SET_CURRENT(before);
/* if we're not in a transaction, start one */
if (PQtransactionStatus(pset.db) == PQTRANS_IDLE)
{
results = PQexec(pset.db, "BEGIN");
OK = AcceptResult(results) &&
(PQresultStatus(results) == PGRES_COMMAND_OK);
ClearOrSaveResult(results);
if (!OK)
return false;
started_txn = true;
}
/* Send DECLARE CURSOR */
initPQExpBuffer(&buf);
appendPQExpBuffer(&buf, "DECLARE _psql_cursor NO SCROLL CURSOR FOR\n%s",
query);
results = PQexec(pset.db, buf.data);
OK = AcceptResult(results) &&
(PQresultStatus(results) == PGRES_COMMAND_OK);
ClearOrSaveResult(results);
termPQExpBuffer(&buf);
if (!OK)
goto cleanup;
if (pset.timing)
{
INSTR_TIME_SET_CURRENT(after);
INSTR_TIME_SUBTRACT(after, before);
*elapsed_msec += INSTR_TIME_GET_MILLISEC(after);
}
/*
* In \gset mode, we force the fetch count to be 2, so that we will throw
* the appropriate error if the query returns more than one row.
*/
if (pset.gset_prefix)
fetch_count = 2;
else
fetch_count = pset.fetch_count;
snprintf(fetch_cmd, sizeof(fetch_cmd),
"FETCH FORWARD %d FROM _psql_cursor",
fetch_count);
/* prepare to write output to \g argument, if any */
if (pset.gfname)
{
if (!openQueryOutputFile(pset.gfname, &fout, &is_pipe))
{
OK = false;
goto cleanup;
}
if (is_pipe)
disable_sigpipe_trap();
}
else
{
fout = pset.queryFout;
is_pipe = false; /* doesn't matter */
}
/* clear any pre-existing error indication on the output stream */
clearerr(fout);
for (;;)
{
if (pset.timing)
INSTR_TIME_SET_CURRENT(before);
/* get fetch_count tuples at a time */
results = PQexec(pset.db, fetch_cmd);
if (pset.timing)
{
INSTR_TIME_SET_CURRENT(after);
INSTR_TIME_SUBTRACT(after, before);
*elapsed_msec += INSTR_TIME_GET_MILLISEC(after);
}
if (PQresultStatus(results) != PGRES_TUPLES_OK)
{
/* shut down pager before printing error message */
if (is_pager)
{
ClosePager(fout);
is_pager = false;
}
OK = AcceptResult(results);
Assert(!OK);
ClearOrSaveResult(results);
break;
}
if (pset.gset_prefix)
{
/* StoreQueryTuple will complain if not exactly one row */
OK = StoreQueryTuple(results);
ClearOrSaveResult(results);
break;
}
/* Note we do not deal with \gexec or \crosstabview modes here */
ntuples = PQntuples(results);
if (ntuples < fetch_count)
{
/* this is the last result set, so allow footer decoration */
my_popt.topt.stop_table = true;
}
else if (fout == stdout && !is_pager)
{
/*
* If query requires multiple result sets, hack to ensure that
* only one pager instance is used for the whole mess
*/
fout = PageOutput(INT_MAX, &(my_popt.topt));
is_pager = true;
}
printQuery(results, &my_popt, fout, is_pager, pset.logfile);
ClearOrSaveResult(results);
/* after the first result set, disallow header decoration */
my_popt.topt.start_table = false;
my_popt.topt.prior_records += ntuples;
/*
* Make sure to flush the output stream, so intermediate results are
* visible to the client immediately. We check the results because if
* the pager dies/exits/etc, there's no sense throwing more data at
* it.
*/
flush_error = fflush(fout);
/*
* Check if we are at the end, if a cancel was pressed, or if there
* were any errors either trying to flush out the results, or more
* generally on the output stream at all. If we hit any errors
* writing things to the stream, we presume $PAGER has disappeared and
* stop bothering to pull down more data.
*/
if (ntuples < fetch_count || cancel_pressed || flush_error ||
ferror(fout))
break;
}
if (pset.gfname)
{
/* close \g argument file/pipe */
if (is_pipe)
{
pclose(fout);
restore_sigpipe_trap();
}
else
fclose(fout);
}
else if (is_pager)
{
/* close transient pager */
ClosePager(fout);
}
cleanup:
if (pset.timing)
INSTR_TIME_SET_CURRENT(before);
/*
* We try to close the cursor on either success or failure, but on failure
* ignore the result (it's probably just a bleat about being in an aborted
* transaction)
*/
results = PQexec(pset.db, "CLOSE _psql_cursor");
if (OK)
{
OK = AcceptResult(results) &&
(PQresultStatus(results) == PGRES_COMMAND_OK);
ClearOrSaveResult(results);
}
else
PQclear(results);
if (started_txn)
{
results = PQexec(pset.db, OK ? "COMMIT" : "ROLLBACK");
OK &= AcceptResult(results) &&
(PQresultStatus(results) == PGRES_COMMAND_OK);
ClearOrSaveResult(results);
}
if (pset.timing)
{
INSTR_TIME_SET_CURRENT(after);
INSTR_TIME_SUBTRACT(after, before);
*elapsed_msec += INSTR_TIME_GET_MILLISEC(after);
}
return OK;
}
/*
* SendQuery: send the query string to the backend
* (and print out results)
*
* Note: This is the "front door" way to send a query. That is, use it to
* send queries actually entered by the user. These queries will be subject to
* single step mode.
* To send "back door" queries (generated by slash commands, etc.) in a
* controlled way, use PSQLexec().
*
* Returns true if the query executed successfully, false otherwise.
*/
bool
SendQuery(const char *query)
{
PGresult *results;
PGTransactionStatusType transaction_status;
double elapsed_msec = 0;
bool OK = false;
int i;
bool on_error_rollback_savepoint = false;
static bool on_error_rollback_warning = false;
if (!pset.db)
{
psql_error("You are currently not connected to a database.\n");
goto sendquery_cleanup;
}
if (pset.singlestep)
{
char buf[3];
fflush(stderr);
printf(_("***(Single step mode: verify command)*******************************************\n"
"%s\n"
"***(press return to proceed or enter x and return to cancel)********************\n"),
query);
fflush(stdout);
if (fgets(buf, sizeof(buf), stdin) != NULL)
if (buf[0] == 'x')
goto sendquery_cleanup;
if (cancel_pressed)
goto sendquery_cleanup;
}
else if (pset.echo == PSQL_ECHO_QUERIES)
{
puts(query);
fflush(stdout);
}
if (pset.logfile)
{
fprintf(pset.logfile,
_("********* QUERY **********\n"
"%s\n"
"**************************\n\n"), query);
fflush(pset.logfile);
}
SetCancelConn();
transaction_status = PQtransactionStatus(pset.db);
if (transaction_status == PQTRANS_IDLE &&
!pset.autocommit &&
!command_no_begin(query))
{
results = PQexec(pset.db, "BEGIN");
if (PQresultStatus(results) != PGRES_COMMAND_OK)
{
psql_error("%s", PQerrorMessage(pset.db));
ClearOrSaveResult(results);
ResetCancelConn();
goto sendquery_cleanup;
}
ClearOrSaveResult(results);
transaction_status = PQtransactionStatus(pset.db);
}
if (transaction_status == PQTRANS_INTRANS &&
pset.on_error_rollback != PSQL_ERROR_ROLLBACK_OFF &&
(pset.cur_cmd_interactive ||
pset.on_error_rollback == PSQL_ERROR_ROLLBACK_ON))
{
if (on_error_rollback_warning == false && pset.sversion < 80000)
{
char sverbuf[32];
psql_error("The server (version %s) does not support savepoints for ON_ERROR_ROLLBACK.\n",
formatPGVersionNumber(pset.sversion, false,
sverbuf, sizeof(sverbuf)));
on_error_rollback_warning = true;
}
else
{
results = PQexec(pset.db, "SAVEPOINT pg_psql_temporary_savepoint");
if (PQresultStatus(results) != PGRES_COMMAND_OK)
{
psql_error("%s", PQerrorMessage(pset.db));
ClearOrSaveResult(results);
ResetCancelConn();
goto sendquery_cleanup;
}
ClearOrSaveResult(results);
on_error_rollback_savepoint = true;
}
}
if (pset.fetch_count <= 0 || pset.gexec_flag ||
pset.crosstab_flag || !is_select_command(query))
{
/* Default fetch-it-all-and-print mode */
instr_time before,
after;
if (pset.timing)
INSTR_TIME_SET_CURRENT(before);
results = PQexec(pset.db, query);
/* these operations are included in the timing result: */
ResetCancelConn();
OK = ProcessResult(&results);
if (pset.timing)
{
INSTR_TIME_SET_CURRENT(after);
INSTR_TIME_SUBTRACT(after, before);
elapsed_msec = INSTR_TIME_GET_MILLISEC(after);
}
/* but printing results isn't: */
if (OK && results)
OK = PrintQueryResults(results);
}
else
{
/* Fetch-in-segments mode */
OK = ExecQueryUsingCursor(query, &elapsed_msec);
ResetCancelConn();
results = NULL; /* PQclear(NULL) does nothing */
}
if (!OK && pset.echo == PSQL_ECHO_ERRORS)
psql_error("STATEMENT: %s\n", query);
/* If we made a temporary savepoint, possibly release/rollback */
if (on_error_rollback_savepoint)
{
const char *svptcmd = NULL;
transaction_status = PQtransactionStatus(pset.db);
switch (transaction_status)
{
case PQTRANS_INERROR:
/* We always rollback on an error */
svptcmd = "ROLLBACK TO pg_psql_temporary_savepoint";
break;
case PQTRANS_IDLE:
/* If they are no longer in a transaction, then do nothing */
break;
case PQTRANS_INTRANS:
/*
* Do nothing if they are messing with savepoints themselves:
* If the user did RELEASE or ROLLBACK, our savepoint is gone.
* If they issued a SAVEPOINT, releasing ours would remove
* theirs.
*/
if (results &&
(strcmp(PQcmdStatus(results), "SAVEPOINT") == 0 ||
strcmp(PQcmdStatus(results), "RELEASE") == 0 ||
strcmp(PQcmdStatus(results), "ROLLBACK") == 0))
svptcmd = NULL;
else
svptcmd = "RELEASE pg_psql_temporary_savepoint";
break;
case PQTRANS_ACTIVE:
case PQTRANS_UNKNOWN:
default:
OK = false;
/* PQTRANS_UNKNOWN is expected given a broken connection. */
if (transaction_status != PQTRANS_UNKNOWN || ConnectionUp())
psql_error("unexpected transaction status (%d)\n",
transaction_status);
break;
}
if (svptcmd)
{
PGresult *svptres;
svptres = PQexec(pset.db, svptcmd);
if (PQresultStatus(svptres) != PGRES_COMMAND_OK)
{
psql_error("%s", PQerrorMessage(pset.db));
ClearOrSaveResult(svptres);
OK = false;
PQclear(results);
ResetCancelConn();
goto sendquery_cleanup;
}
PQclear(svptres);
}
}
ClearOrSaveResult(results);
/* Possible microtiming output */
if (pset.timing)
printf(_("Time: %.3f ms\n"), elapsed_msec);
/* check for events that may occur during query execution */
if (pset.encoding != PQclientEncoding(pset.db) &&
PQclientEncoding(pset.db) >= 0)
{
/* track effects of SET CLIENT_ENCODING */
pset.encoding = PQclientEncoding(pset.db);
pset.popt.topt.encoding = pset.encoding;
SetVariable(pset.vars, "ENCODING",
pg_encoding_to_char(pset.encoding));
}
PrintNotifications();
/* perform cleanup that should occur after any attempted query */
sendquery_cleanup:
/* reset \g's output-to-filename trigger */
if (pset.gfname)
{
free(pset.gfname);
pset.gfname = NULL;
}
/* reset \gset trigger */
if (pset.gset_prefix)
{
free(pset.gset_prefix);
pset.gset_prefix = NULL;
}
/* reset \gexec trigger */
pset.gexec_flag = false;
/* reset \crosstabview trigger */
pset.crosstab_flag = false;
for (i = 0; i < lengthof(pset.ctv_args); i++)
{
pg_free(pset.ctv_args[i]);
pset.ctv_args[i] = NULL;
}
return OK;
}
static void powa_main(Datum main_arg)
{
char *q1 = "SELECT powa_take_snapshot()";
static char *q2 = "SET application_name = 'POWA collector'";
instr_time begin;
instr_time end;
long time_to_wait;
die_on_too_small_frequency();
/*
Set up signal handlers, then unblock signalsl
*/
pqsignal(SIGHUP, powa_sighup);
pqsignal(SIGTERM, powa_sigterm);
BackgroundWorkerUnblockSignals();
/*
We only connect when powa_frequency >0. If not, powa has been deactivated
*/
if (powa_frequency < 0)
{
elog(LOG, "POWA is deactivated (powa.frequency = %i), exiting",
powa_frequency);
exit(1);
}
// We got here: it means powa_frequency > 0. Let's connect
/*
Connect to POWA database
*/
BackgroundWorkerInitializeConnection(powa_database, NULL);
elog(LOG, "POWA connected to %s", powa_database);
StartTransactionCommand();
SetCurrentStatementStartTimestamp();
SPI_connect();
PushActiveSnapshot(GetTransactionSnapshot());
SPI_execute(q2, false, 0);
SPI_finish();
PopActiveSnapshot();
CommitTransactionCommand();
/*
let's store the current time. It will be used to
calculate a quite stable interval between each measure
*/
while (!got_sigterm)
{
/*
We can get here with a new value of powa_frequency
because of a reload. Let's suicide to disconnect
if this value is <0
*/
if (powa_frequency < 0)
{
elog(LOG, "POWA exits to disconnect from the database now");
exit(1);
}
INSTR_TIME_SET_CURRENT(begin);
ResetLatch(&MyProc->procLatch);
StartTransactionCommand();
SetCurrentStatementStartTimestamp();
SPI_connect();
PushActiveSnapshot(GetTransactionSnapshot());
SPI_execute(q1, false, 0);
SPI_finish();
PopActiveSnapshot();
CommitTransactionCommand();
INSTR_TIME_SET_CURRENT(end);
INSTR_TIME_SUBTRACT(end, begin);
/*
Wait powa.frequency, compensate for work time of last snapshot
*/
/*
If we got off schedule (because of a compact or delete,
just do another operation right now
*/
time_to_wait = powa_frequency - INSTR_TIME_GET_MILLISEC(end);
if (time_to_wait > 0)
{
WaitLatch(&MyProc->procLatch,
WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
time_to_wait);
}
}
proc_exit(0);
}
/*
* Select next block to sample.
*
* Uses linear probing algorithm for picking next block.
*/
static BlockNumber
system_time_nextsampleblock(SampleScanState *node)
{
SystemTimeSamplerData *sampler = (SystemTimeSamplerData *) node->tsm_state;
HeapScanDesc scan = node->ss.ss_currentScanDesc;
instr_time cur_time;
/* First call within scan? */
if (sampler->doneblocks == 0)
{
/* First scan within query? */
if (sampler->step == 0)
{
/* Initialize now that we have scan descriptor */
SamplerRandomState randstate;
/* If relation is empty, there's nothing to scan */
if (scan->rs_nblocks == 0)
return InvalidBlockNumber;
/* We only need an RNG during this setup step */
sampler_random_init_state(sampler->seed, randstate);
/* Compute nblocks/firstblock/step only once per query */
sampler->nblocks = scan->rs_nblocks;
/* Choose random starting block within the relation */
/* (Actually this is the predecessor of the first block visited) */
sampler->firstblock = sampler_random_fract(randstate) *
sampler->nblocks;
/* Find relative prime as step size for linear probing */
sampler->step = random_relative_prime(sampler->nblocks, randstate);
}
/* Reinitialize lb and start_time */
sampler->lb = sampler->firstblock;
INSTR_TIME_SET_CURRENT(sampler->start_time);
}
/* If we've read all blocks in relation, we're done */
if (++sampler->doneblocks > sampler->nblocks)
return InvalidBlockNumber;
/* If we've used up all the allotted time, we're done */
INSTR_TIME_SET_CURRENT(cur_time);
INSTR_TIME_SUBTRACT(cur_time, sampler->start_time);
if (INSTR_TIME_GET_MILLISEC(cur_time) >= sampler->millis)
return InvalidBlockNumber;
/*
* It's probably impossible for scan->rs_nblocks to decrease between scans
* within a query; but just in case, loop until we select a block number
* less than scan->rs_nblocks. We don't care if scan->rs_nblocks has
* increased since the first scan.
*/
do
{
/* Advance lb, using uint64 arithmetic to forestall overflow */
sampler->lb = ((uint64) sampler->lb + sampler->step) % sampler->nblocks;
} while (sampler->lb >= scan->rs_nblocks);
return sampler->lb;
}
