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Reap the benefits of not having to avoid leaking PGresults.

Browse Source 
Remove a bunch of PG_TRY constructs, de-volatilize related
variables, remove some PQclear calls in error paths.
Aside from making the code simpler and shorter, this should
provide some marginal performance gains.

For ease of review, I did not re-indent code within the removed
PG_TRY constructs.  That'll be done in a separate patch.

Author: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Matheus Alcantara <matheusssilv97@gmail.com>
Discussion: https://postgr.es/m/2976982.1748049023@sss.pgh.pa.us
This commit is contained in:
Tom Lane
2025-07-25 16:31:43 -04:00
parent 7d8f595779
commit 80aa9848be
6 changed files with 83 additions and 274 deletions
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96
contrib/dblink/dblink.c
View File

@ -101,8 +101,8 @@ static void materializeQueryResult(FunctionCallInfo fcinfo,
const char *conname,
const char *sql,
bool fail);
static PGresult *storeQueryResult(volatile storeInfo *sinfo, PGconn *conn, const char *sql);
static void storeRow(volatile storeInfo *sinfo, PGresult *res, bool first);
static PGresult *storeQueryResult(storeInfo *sinfo, PGconn *conn, const char *sql);
static void storeRow(storeInfo *sinfo, PGresult *res, bool first);
static remoteConn *getConnectionByName(const char *name);
static HTAB *createConnHash(void);
static remoteConn *createNewConnection(const char *name);
@ -169,14 +169,6 @@ typedef struct remoteConnHashEnt
/* initial number of connection hashes */
#define NUMCONN 16
static char *
xpstrdup(const char *in)
{
if (in == NULL)
return NULL;
return pstrdup(in);
}
pg_noreturn static void
dblink_res_internalerror(PGconn *conn, PGresult *res, const char *p2)
{
@ -870,17 +862,14 @@ static void
materializeResult(FunctionCallInfo fcinfo, PGconn *conn, PGresult *res)
{
ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
TupleDesc tupdesc;
bool is_sql_cmd;
int ntuples;
int nfields;
/* prepTuplestoreResult must have been called previously */
Assert(rsinfo->returnMode == SFRM_Materialize);
PG_TRY();
{
TupleDesc tupdesc;
bool is_sql_cmd;
int ntuples;
int nfields;
if (PQresultStatus(res) == PGRES_COMMAND_OK)
{
is_sql_cmd = true;
@ -988,13 +977,8 @@ materializeResult(FunctionCallInfo fcinfo, PGconn *conn, PGresult *res)
/* clean up GUC settings, if we changed any */
restoreLocalGucs(nestlevel);
}
}
PG_FINALLY();
{
/* be sure to release the libpq result */
PQclear(res);
}
PG_END_TRY();
}
/*
@ -1013,16 +997,17 @@ materializeQueryResult(FunctionCallInfo fcinfo,
bool fail)
{
ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
PGresult *volatile res = NULL;
volatile storeInfo sinfo = {0};
/* prepTuplestoreResult must have been called previously */
Assert(rsinfo->returnMode == SFRM_Materialize);
sinfo.fcinfo = fcinfo;
/* Use a PG_TRY block to ensure we pump libpq dry of results */
PG_TRY();
{
storeInfo sinfo = {0};
PGresult *res;
sinfo.fcinfo = fcinfo;
/* Create short-lived memory context for data conversions */
sinfo.tmpcontext = AllocSetContextCreate(CurrentMemoryContext,
"dblink temporary context",
@ -1035,14 +1020,7 @@ materializeQueryResult(FunctionCallInfo fcinfo,
(PQresultStatus(res) != PGRES_COMMAND_OK &&
PQresultStatus(res) != PGRES_TUPLES_OK))
{
/*
* dblink_res_error will clear the passed PGresult, so we need
* this ugly dance to avoid doing so twice during error exit
*/
PGresult *res1 = res;
res = NULL;
dblink_res_error(conn, conname, res1, fail,
dblink_res_error(conn, conname, res, fail,
"while executing query");
/* if fail isn't set, we'll return an empty query result */
}
@ -1081,7 +1059,6 @@ materializeQueryResult(FunctionCallInfo fcinfo,
tuplestore_puttuple(tupstore, tuple);
PQclear(res);
res = NULL;
}
else
{
@ -1090,26 +1067,20 @@ materializeQueryResult(FunctionCallInfo fcinfo,
Assert(rsinfo->setResult != NULL);
PQclear(res);
res = NULL;
}
/* clean up data conversion short-lived memory context */
if (sinfo.tmpcontext != NULL)
MemoryContextDelete(sinfo.tmpcontext);
sinfo.tmpcontext = NULL;
PQclear(sinfo.last_res);
sinfo.last_res = NULL;
PQclear(sinfo.cur_res);
sinfo.cur_res = NULL;
}
PG_CATCH();
{
/* be sure to release any libpq result we collected */
PQclear(res);
PQclear(sinfo.last_res);
PQclear(sinfo.cur_res);
/* and clear out any pending data in libpq */
PGresult *res;
/* be sure to clear out any pending data in libpq */
while ((res = libpqsrv_get_result(conn, dblink_we_get_result)) !=
NULL)
PQclear(res);
@ -1122,7 +1093,7 @@ materializeQueryResult(FunctionCallInfo fcinfo,
* Execute query, and send any result rows to sinfo->tuplestore.
*/
static PGresult *
storeQueryResult(volatile storeInfo *sinfo, PGconn *conn, const char *sql)
storeQueryResult(storeInfo *sinfo, PGconn *conn, const char *sql)
{
bool first = true;
int nestlevel = -1;
@ -1190,7 +1161,7 @@ storeQueryResult(volatile storeInfo *sinfo, PGconn *conn, const char *sql)
* (in this case the PGresult might contain either zero or one row).
*/
static void
storeRow(volatile storeInfo *sinfo, PGresult *res, bool first)
storeRow(storeInfo *sinfo, PGresult *res, bool first)
{
int nfields = PQnfields(res);
HeapTuple tuple;
@ -2795,10 +2766,13 @@ dblink_connstr_check(const char *connstr)
/*
* Report an error received from the remote server
*
* res: the received error result (will be freed)
* res: the received error result
* fail: true for ERROR ereport, false for NOTICE
* fmt and following args: sprintf-style format and values for errcontext;
* the resulting string should be worded like "while <some action>"
*
* If "res" is not NULL, it'll be PQclear'ed here (unless we throw error,
* in which case memory context cleanup will clear it eventually).
*/
static void
dblink_res_error(PGconn *conn, const char *conname, PGresult *res,
@ -2806,15 +2780,11 @@ dblink_res_error(PGconn *conn, const char *conname, PGresult *res,
{
int level;
char *pg_diag_sqlstate = PQresultErrorField(res, PG_DIAG_SQLSTATE);
char *pg_diag_message_primary = PQresultErrorField(res, PG_DIAG_MESSAGE_PRIMARY);
char *pg_diag_message_detail = PQresultErrorField(res, PG_DIAG_MESSAGE_DETAIL);
char *pg_diag_message_hint = PQresultErrorField(res, PG_DIAG_MESSAGE_HINT);
char *pg_diag_context = PQresultErrorField(res, PG_DIAG_CONTEXT);
char *message_primary = PQresultErrorField(res, PG_DIAG_MESSAGE_PRIMARY);
char *message_detail = PQresultErrorField(res, PG_DIAG_MESSAGE_DETAIL);
char *message_hint = PQresultErrorField(res, PG_DIAG_MESSAGE_HINT);
char *message_context = PQresultErrorField(res, PG_DIAG_CONTEXT);
int sqlstate;
char *message_primary;
char *message_detail;
char *message_hint;
char *message_context;
va_list ap;
char dblink_context_msg[512];
@ -2832,11 +2802,6 @@ dblink_res_error(PGconn *conn, const char *conname, PGresult *res,
else
sqlstate = ERRCODE_CONNECTION_FAILURE;
message_primary = xpstrdup(pg_diag_message_primary);
message_detail = xpstrdup(pg_diag_message_detail);
message_hint = xpstrdup(pg_diag_message_hint);
message_context = xpstrdup(pg_diag_context);
/*
* If we don't get a message from the PGresult, try the PGconn. This is
* needed because for connection-level failures, PQgetResult may just
@ -2845,14 +2810,6 @@ dblink_res_error(PGconn *conn, const char *conname, PGresult *res,
if (message_primary == NULL)
message_primary = pchomp(PQerrorMessage(conn));
/*
* Now that we've copied all the data we need out of the PGresult, it's
* safe to free it. We must do this to avoid PGresult leakage. We're
* leaking all the strings too, but those are in palloc'd memory that will
* get cleaned up eventually.
*/
PQclear(res);
/*
* Format the basic errcontext string. Below, we'll add on something
* about the connection name. That's a violation of the translatability
@ -2877,6 +2834,7 @@ dblink_res_error(PGconn *conn, const char *conname, PGresult *res,
dblink_context_msg, conname)) :
(errcontext("%s on unnamed dblink connection",
dblink_context_msg))));
PQclear(res);
}
/*

52
contrib/postgres_fdw/connection.c
View File

@ -815,7 +815,7 @@ static void
do_sql_command_begin(PGconn *conn, const char *sql)
{
if (!PQsendQuery(conn, sql))
pgfdw_report_error(ERROR, NULL, conn, false, sql);
pgfdw_report_error(ERROR, NULL, conn, sql);
}
static void
@ -830,10 +830,10 @@ do_sql_command_end(PGconn *conn, const char *sql, bool consume_input)
* would be large compared to the overhead of PQconsumeInput.)
*/
if (consume_input && !PQconsumeInput(conn))
pgfdw_report_error(ERROR, NULL, conn, false, sql);
pgfdw_report_error(ERROR, NULL, conn, sql);
res = pgfdw_get_result(conn);
if (PQresultStatus(res) != PGRES_COMMAND_OK)
pgfdw_report_error(ERROR, res, conn, true, sql);
pgfdw_report_error(ERROR, res, conn, sql);
PQclear(res);
}
@ -967,22 +967,21 @@ pgfdw_get_result(PGconn *conn)
* Report an error we got from the remote server.
*
* elevel: error level to use (typically ERROR, but might be less)
* res: PGresult containing the error
* res: PGresult containing the error (might be NULL)
* conn: connection we did the query on
* clear: if true, PQclear the result (otherwise caller will handle it)
* sql: NULL, or text of remote command we tried to execute
*
* If "res" is not NULL, it'll be PQclear'ed here (unless we throw error,
* in which case memory context cleanup will clear it eventually).
*
* Note: callers that choose not to throw ERROR for a remote error are
* responsible for making sure that the associated ConnCacheEntry gets
* marked with have_error = true.
*/
void
pgfdw_report_error(int elevel, PGresult *res, PGconn *conn,
bool clear, const char *sql)
const char *sql)
{
/* If requested, PGresult must be released before leaving this function. */
PG_TRY();
{
char *diag_sqlstate = PQresultErrorField(res, PG_DIAG_SQLSTATE);
char *message_primary = PQresultErrorField(res, PG_DIAG_MESSAGE_PRIMARY);
char *message_detail = PQresultErrorField(res, PG_DIAG_MESSAGE_DETAIL);
@ -1016,13 +1015,7 @@ pgfdw_report_error(int elevel, PGresult *res, PGconn *conn,
message_hint ? errhint("%s", message_hint) : 0,
message_context ? errcontext("%s", message_context) : 0,
sql ? errcontext("remote SQL command: %s", sql) : 0));
}
PG_FINALLY();
{
if (clear)
PQclear(res);
}
PG_END_TRY();
}
/*
@ -1545,7 +1538,7 @@ pgfdw_exec_cleanup_query_begin(PGconn *conn, const char *query)
*/
if (!PQsendQuery(conn, query))
{
pgfdw_report_error(WARNING, NULL, conn, false, query);
pgfdw_report_error(WARNING, NULL, conn, query);
return false;
}
@ -1570,7 +1563,7 @@ pgfdw_exec_cleanup_query_end(PGconn *conn, const char *query,
*/
if (consume_input && !PQconsumeInput(conn))
{
pgfdw_report_error(WARNING, NULL, conn, false, query);
pgfdw_report_error(WARNING, NULL, conn, query);
return false;
}
@ -1582,7 +1575,7 @@ pgfdw_exec_cleanup_query_end(PGconn *conn, const char *query,
(errmsg("could not get query result due to timeout"),
errcontext("remote SQL command: %s", query)));
else
pgfdw_report_error(WARNING, NULL, conn, false, query);
pgfdw_report_error(WARNING, NULL, conn, query);
return false;
}
@ -1590,7 +1583,7 @@ pgfdw_exec_cleanup_query_end(PGconn *conn, const char *query,
/* Issue a warning if not successful. */
if (PQresultStatus(result) != PGRES_COMMAND_OK)
{
pgfdw_report_error(WARNING, result, conn, true, query);
pgfdw_report_error(WARNING, result, conn, query);
return ignore_errors;
}
PQclear(result);
@ -1618,17 +1611,12 @@ pgfdw_get_cleanup_result(PGconn *conn, TimestampTz endtime,
PGresult **result,
bool *timed_out)
{
volatile bool failed = false;
PGresult *volatile last_res = NULL;
bool failed = false;
PGresult *last_res = NULL;
int canceldelta = RETRY_CANCEL_TIMEOUT * 2;
*result = NULL;
*timed_out = false;
/* In what follows, do not leak any PGresults on an error. */
PG_TRY();
{
int canceldelta = RETRY_CANCEL_TIMEOUT * 2;
for (;;)
{
PGresult *res;
@ -1706,15 +1694,7 @@ pgfdw_get_cleanup_result(PGconn *conn, TimestampTz endtime,
PQclear(last_res);
last_res = res;
}
exit: ;
}
PG_CATCH();
{
PQclear(last_res);
PG_RE_THROW();
}
PG_END_TRY();
exit:
if (failed)
PQclear(last_res);
else

163
contrib/postgres_fdw/postgres_fdw.c
View File

@ -1702,13 +1702,9 @@ postgresReScanForeignScan(ForeignScanState *node)
return;
}
/*
* We don't use a PG_TRY block here, so be careful not to throw error
* without releasing the PGresult.
*/
res = pgfdw_exec_query(fsstate->conn, sql, fsstate->conn_state);
if (PQresultStatus(res) != PGRES_COMMAND_OK)
pgfdw_report_error(ERROR, res, fsstate->conn, true, sql);
pgfdw_report_error(ERROR, res, fsstate->conn, sql);
PQclear(res);
/* Now force a fresh FETCH. */
@ -3608,11 +3604,7 @@ get_remote_estimate(const char *sql, PGconn *conn,
double *rows, int *width,
Cost *startup_cost, Cost *total_cost)
{
PGresult *volatile res = NULL;
/* PGresult must be released before leaving this function. */
PG_TRY();
{
PGresult *res;
char *line;
char *p;
int n;
@ -3622,7 +3614,7 @@ get_remote_estimate(const char *sql, PGconn *conn,
*/
res = pgfdw_exec_query(conn, sql, NULL);
if (PQresultStatus(res) != PGRES_TUPLES_OK)
pgfdw_report_error(ERROR, res, conn, false, sql);
pgfdw_report_error(ERROR, res, conn, sql);
/*
* Extract cost numbers for topmost plan node. Note we search for a
@ -3637,12 +3629,7 @@ get_remote_estimate(const char *sql, PGconn *conn,
startup_cost, total_cost, rows, width);
if (n != 4)
elog(ERROR, "could not interpret EXPLAIN output: \"%s\"", line);
}
PG_FINALLY();
{
PQclear(res);
}
PG_END_TRY();
}
/*
@ -3782,17 +3769,14 @@ create_cursor(ForeignScanState *node)
*/
if (!PQsendQueryParams(conn, buf.data, numParams,
NULL, values, NULL, NULL, 0))
pgfdw_report_error(ERROR, NULL, conn, false, buf.data);
pgfdw_report_error(ERROR, NULL, conn, buf.data);
/*
* Get the result, and check for success.
*
* We don't use a PG_TRY block here, so be careful not to throw error
* without releasing the PGresult.
*/
res = pgfdw_get_result(conn);
if (PQresultStatus(res) != PGRES_COMMAND_OK)
pgfdw_report_error(ERROR, res, conn, true, fsstate->query);
pgfdw_report_error(ERROR, res, conn, fsstate->query);
PQclear(res);
/* Mark the cursor as created, and show no tuples have been retrieved */
@ -3814,7 +3798,10 @@ static void
fetch_more_data(ForeignScanState *node)
{
PgFdwScanState *fsstate = (PgFdwScanState *) node->fdw_state;
PGresult *volatile res = NULL;
PGconn *conn = fsstate->conn;
PGresult *res;
int numrows;
int i;
MemoryContext oldcontext;
/*
@ -3825,13 +3812,6 @@ fetch_more_data(ForeignScanState *node)
MemoryContextReset(fsstate->batch_cxt);
oldcontext = MemoryContextSwitchTo(fsstate->batch_cxt);
/* PGresult must be released before leaving this function. */
PG_TRY();
{
PGconn *conn = fsstate->conn;
int numrows;
int i;
if (fsstate->async_capable)
{
Assert(fsstate->conn_state->pendingAreq);
@ -3843,7 +3823,7 @@ fetch_more_data(ForeignScanState *node)
res = pgfdw_get_result(conn);
/* On error, report the original query, not the FETCH. */
if (PQresultStatus(res) != PGRES_TUPLES_OK)
pgfdw_report_error(ERROR, res, conn, false, fsstate->query);
pgfdw_report_error(ERROR, res, conn, fsstate->query);
/* Reset per-connection state */
fsstate->conn_state->pendingAreq = NULL;
@ -3859,7 +3839,7 @@ fetch_more_data(ForeignScanState *node)
res = pgfdw_exec_query(conn, sql, fsstate->conn_state);
/* On error, report the original query, not the FETCH. */
if (PQresultStatus(res) != PGRES_TUPLES_OK)
pgfdw_report_error(ERROR, res, conn, false, fsstate->query);
pgfdw_report_error(ERROR, res, conn, fsstate->query);
}
/* Convert the data into HeapTuples */
@ -3887,12 +3867,8 @@ fetch_more_data(ForeignScanState *node)
/* Must be EOF if we didn't get as many tuples as we asked for. */
fsstate->eof_reached = (numrows < fsstate->fetch_size);
}
PG_FINALLY();
{
PQclear(res);
}
PG_END_TRY();
MemoryContextSwitchTo(oldcontext);
}
@ -3966,14 +3942,9 @@ close_cursor(PGconn *conn, unsigned int cursor_number,
PGresult *res;
snprintf(sql, sizeof(sql), "CLOSE c%u", cursor_number);
/*
* We don't use a PG_TRY block here, so be careful not to throw error
* without releasing the PGresult.
*/
res = pgfdw_exec_query(conn, sql, conn_state);
if (PQresultStatus(res) != PGRES_COMMAND_OK)
pgfdw_report_error(ERROR, res, conn, true, sql);
pgfdw_report_error(ERROR, res, conn, sql);
PQclear(res);
}
@ -4181,18 +4152,15 @@ execute_foreign_modify(EState *estate,
NULL,
NULL,
0))
pgfdw_report_error(ERROR, NULL, fmstate->conn, false, fmstate->query);
pgfdw_report_error(ERROR, NULL, fmstate->conn, fmstate->query);
/*
* Get the result, and check for success.
*
* We don't use a PG_TRY block here, so be careful not to throw error
* without releasing the PGresult.
*/
res = pgfdw_get_result(fmstate->conn);
if (PQresultStatus(res) !=
(fmstate->has_returning ? PGRES_TUPLES_OK : PGRES_COMMAND_OK))
pgfdw_report_error(ERROR, res, fmstate->conn, true, fmstate->query);
pgfdw_report_error(ERROR, res, fmstate->conn, fmstate->query);
/* Check number of rows affected, and fetch RETURNING tuple if any */
if (fmstate->has_returning)
@ -4251,17 +4219,14 @@ prepare_foreign_modify(PgFdwModifyState *fmstate)
fmstate->query,
0,
NULL))
pgfdw_report_error(ERROR, NULL, fmstate->conn, false, fmstate->query);
pgfdw_report_error(ERROR, NULL, fmstate->conn, fmstate->query);
/*
* Get the result, and check for success.
*
* We don't use a PG_TRY block here, so be careful not to throw error
* without releasing the PGresult.
*/
res = pgfdw_get_result(fmstate->conn);
if (PQresultStatus(res) != PGRES_COMMAND_OK)
pgfdw_report_error(ERROR, res, fmstate->conn, true, fmstate->query);
pgfdw_report_error(ERROR, res, fmstate->conn, fmstate->query);
PQclear(res);
/* This action shows that the prepare has been done. */
@ -4352,16 +4317,11 @@ convert_prep_stmt_params(PgFdwModifyState *fmstate,
/*
* store_returning_result
* Store the result of a RETURNING clause
*
* On error, be sure to release the PGresult on the way out. Callers do not
* have PG_TRY blocks to ensure this happens.
*/
static void
store_returning_result(PgFdwModifyState *fmstate,
TupleTableSlot *slot, PGresult *res)
{
PG_TRY();
{
HeapTuple newtup;
newtup = make_tuple_from_result_row(res, 0,
@ -4376,13 +4336,6 @@ store_returning_result(PgFdwModifyState *fmstate,
* heaptuples directly, so allow for conversion.
*/
ExecForceStoreHeapTuple(newtup, slot, true);
}
PG_CATCH();
{
PQclear(res);
PG_RE_THROW();
}
PG_END_TRY();
}
/*
@ -4418,14 +4371,9 @@ deallocate_query(PgFdwModifyState *fmstate)
return;
snprintf(sql, sizeof(sql), "DEALLOCATE %s", fmstate->p_name);
/*
* We don't use a PG_TRY block here, so be careful not to throw error
* without releasing the PGresult.
*/
res = pgfdw_exec_query(fmstate->conn, sql, fmstate->conn_state);
if (PQresultStatus(res) != PGRES_COMMAND_OK)
pgfdw_report_error(ERROR, res, fmstate->conn, true, sql);
pgfdw_report_error(ERROR, res, fmstate->conn, sql);
PQclear(res);
pfree(fmstate->p_name);
fmstate->p_name = NULL;
@ -4593,7 +4541,7 @@ execute_dml_stmt(ForeignScanState *node)
*/
if (!PQsendQueryParams(dmstate->conn, dmstate->query, numParams,
NULL, values, NULL, NULL, 0))
pgfdw_report_error(ERROR, NULL, dmstate->conn, false, dmstate->query);
pgfdw_report_error(ERROR, NULL, dmstate->conn, dmstate->query);
/*
* Get the result, and check for success.
@ -4601,7 +4549,7 @@ execute_dml_stmt(ForeignScanState *node)
dmstate->result = pgfdw_get_result(dmstate->conn);
if (PQresultStatus(dmstate->result) !=
(dmstate->has_returning ? PGRES_TUPLES_OK : PGRES_COMMAND_OK))
pgfdw_report_error(ERROR, dmstate->result, dmstate->conn, true,
pgfdw_report_error(ERROR, dmstate->result, dmstate->conn,
dmstate->query);
/*
@ -4947,7 +4895,7 @@ postgresAnalyzeForeignTable(Relation relation,
UserMapping *user;
PGconn *conn;
StringInfoData sql;
PGresult *volatile res = NULL;
PGresult *res;
/* Return the row-analysis function pointer */
*func = postgresAcquireSampleRowsFunc;
@ -4973,22 +4921,14 @@ postgresAnalyzeForeignTable(Relation relation,
initStringInfo(&sql);
deparseAnalyzeSizeSql(&sql, relation);
/* In what follows, do not risk leaking any PGresults. */
PG_TRY();
{
res = pgfdw_exec_query(conn, sql.data, NULL);
if (PQresultStatus(res) != PGRES_TUPLES_OK)
pgfdw_report_error(ERROR, res, conn, false, sql.data);
pgfdw_report_error(ERROR, res, conn, sql.data);
if (PQntuples(res) != 1 || PQnfields(res) != 1)
elog(ERROR, "unexpected result from deparseAnalyzeSizeSql query");
*totalpages = strtoul(PQgetvalue(res, 0, 0), NULL, 10);
}
PG_FINALLY();
{
PQclear(res);
}
PG_END_TRY();
ReleaseConnection(conn);
@ -5009,9 +4949,9 @@ postgresGetAnalyzeInfoForForeignTable(Relation relation, bool *can_tablesample)
UserMapping *user;
PGconn *conn;
StringInfoData sql;
PGresult *volatile res = NULL;
volatile double reltuples = -1;
volatile char relkind = 0;
PGresult *res;
double reltuples;
char relkind;
/* assume the remote relation does not support TABLESAMPLE */
*can_tablesample = false;
@ -5030,24 +4970,15 @@ postgresGetAnalyzeInfoForForeignTable(Relation relation, bool *can_tablesample)
initStringInfo(&sql);
deparseAnalyzeInfoSql(&sql, relation);
/* In what follows, do not risk leaking any PGresults. */
PG_TRY();
{
res = pgfdw_exec_query(conn, sql.data, NULL);
if (PQresultStatus(res) != PGRES_TUPLES_OK)
pgfdw_report_error(ERROR, res, conn, false, sql.data);
pgfdw_report_error(ERROR, res, conn, sql.data);
if (PQntuples(res) != 1 || PQnfields(res) != 2)
elog(ERROR, "unexpected result from deparseAnalyzeInfoSql query");
reltuples = strtod(PQgetvalue(res, 0, 0), NULL);
relkind = *(PQgetvalue(res, 0, 1));
}
PG_FINALLY();
{
if (res)
PQclear(res);
}
PG_END_TRY();
ReleaseConnection(conn);
@ -5090,7 +5021,9 @@ postgresAcquireSampleRowsFunc(Relation relation, int elevel,
double reltuples;
unsigned int cursor_number;
StringInfoData sql;
PGresult *volatile res = NULL;
PGresult *res;
char fetch_sql[64];
int fetch_size;
ListCell *lc;
/* Initialize workspace state */
@ -5267,17 +5200,10 @@ postgresAcquireSampleRowsFunc(Relation relation, int elevel,
deparseAnalyzeSql(&sql, relation, method, sample_frac, &astate.retrieved_attrs);
/* In what follows, do not risk leaking any PGresults. */
PG_TRY();
{
char fetch_sql[64];
int fetch_size;
res = pgfdw_exec_query(conn, sql.data, NULL);
if (PQresultStatus(res) != PGRES_COMMAND_OK)
pgfdw_report_error(ERROR, res, conn, false, sql.data);
pgfdw_report_error(ERROR, res, conn, sql.data);
PQclear(res);
res = NULL;
/*
* Determine the fetch size. The default is arbitrary, but shouldn't
@ -5328,7 +5254,7 @@ postgresAcquireSampleRowsFunc(Relation relation, int elevel,
res = pgfdw_exec_query(conn, fetch_sql, NULL);
/* On error, report the original query, not the FETCH. */
if (PQresultStatus(res) != PGRES_TUPLES_OK)
pgfdw_report_error(ERROR, res, conn, false, sql.data);
pgfdw_report_error(ERROR, res, conn, sql.data);
/* Process whatever we got. */
numrows = PQntuples(res);
@ -5336,7 +5262,6 @@ postgresAcquireSampleRowsFunc(Relation relation, int elevel,
analyze_row_processor(res, i, &astate);
PQclear(res);
res = NULL;
/* Must be EOF if we didn't get all the rows requested. */
if (numrows < fetch_size)
@ -5345,13 +5270,6 @@ postgresAcquireSampleRowsFunc(Relation relation, int elevel,
/* Close the cursor, just to be tidy. */
close_cursor(conn, cursor_number, NULL);
}
PG_CATCH();
{
PQclear(res);
PG_RE_THROW();
}
PG_END_TRY();
ReleaseConnection(conn);
@ -5463,7 +5381,7 @@ postgresImportForeignSchema(ImportForeignSchemaStmt *stmt, Oid serverOid)
UserMapping *mapping;
PGconn *conn;
StringInfoData buf;
PGresult *volatile res = NULL;
PGresult *res;
int numrows,
i;
ListCell *lc;
@ -5502,16 +5420,13 @@ postgresImportForeignSchema(ImportForeignSchemaStmt *stmt, Oid serverOid)
/* Create workspace for strings */
initStringInfo(&buf);
/* In what follows, do not risk leaking any PGresults. */
PG_TRY();
{
/* Check that the schema really exists */
appendStringInfoString(&buf, "SELECT 1 FROM pg_catalog.pg_namespace WHERE nspname = ");
deparseStringLiteral(&buf, stmt->remote_schema);
res = pgfdw_exec_query(conn, buf.data, NULL);
if (PQresultStatus(res) != PGRES_TUPLES_OK)
pgfdw_report_error(ERROR, res, conn, false, buf.data);
pgfdw_report_error(ERROR, res, conn, buf.data);
if (PQntuples(res) != 1)
ereport(ERROR,
@ -5520,7 +5435,6 @@ postgresImportForeignSchema(ImportForeignSchemaStmt *stmt, Oid serverOid)
stmt->remote_schema, server->servername)));
PQclear(res);
res = NULL;
resetStringInfo(&buf);
/*
@ -5628,7 +5542,7 @@ postgresImportForeignSchema(ImportForeignSchemaStmt *stmt, Oid serverOid)
/* Fetch the data */
res = pgfdw_exec_query(conn, buf.data, NULL);
if (PQresultStatus(res) != PGRES_TUPLES_OK)
pgfdw_report_error(ERROR, res, conn, false, buf.data);
pgfdw_report_error(ERROR, res, conn, buf.data);
/* Process results */
numrows = PQntuples(res);
@ -5733,12 +5647,7 @@ postgresImportForeignSchema(ImportForeignSchemaStmt *stmt, Oid serverOid)
commands = lappend(commands, pstrdup(buf.data));
}
}
PG_FINALLY();
{
PQclear(res);
}
PG_END_TRY();
ReleaseConnection(conn);
@ -7406,7 +7315,7 @@ postgresForeignAsyncNotify(AsyncRequest *areq)
/* On error, report the original query, not the FETCH. */
if (!PQconsumeInput(fsstate->conn))
pgfdw_report_error(ERROR, NULL, fsstate->conn, false, fsstate->query);
pgfdw_report_error(ERROR, NULL, fsstate->conn, fsstate->query);
fetch_more_data(node);
@ -7505,7 +7414,7 @@ fetch_more_data_begin(AsyncRequest *areq)
fsstate->fetch_size, fsstate->cursor_number);
if (!PQsendQuery(fsstate->conn, sql))
pgfdw_report_error(ERROR, NULL, fsstate->conn, false, fsstate->query);
pgfdw_report_error(ERROR, NULL, fsstate->conn, fsstate->query);
/* Remember that the request is in process */
fsstate->conn_state->pendingAreq = areq;

2
contrib/postgres_fdw/postgres_fdw.h
View File

@ -167,7 +167,7 @@ extern PGresult *pgfdw_get_result(PGconn *conn);
extern PGresult *pgfdw_exec_query(PGconn *conn, const char *query,
PgFdwConnState *state);
extern void pgfdw_report_error(int elevel, PGresult *res, PGconn *conn,
bool clear, const char *sql);
const char *sql);
/* in option.c */
extern int ExtractConnectionOptions(List *defelems,

31
src/backend/replication/libpqwalreceiver/libpqwalreceiver.c
View File

@ -421,31 +421,22 @@ libpqrcv_identify_system(WalReceiverConn *conn, TimeLineID *primary_tli)
"IDENTIFY_SYSTEM",
WAIT_EVENT_LIBPQWALRECEIVER_RECEIVE);
if (PQresultStatus(res) != PGRES_TUPLES_OK)
{
PQclear(res);
ereport(ERROR,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
errmsg("could not receive database system identifier and timeline ID from "
"the primary server: %s",
pchomp(PQerrorMessage(conn->streamConn)))));
}
/*
* IDENTIFY_SYSTEM returns 3 columns in 9.3 and earlier, and 4 columns in
* 9.4 and onwards.
*/
if (PQnfields(res) < 3 || PQntuples(res) != 1)
{
int ntuples = PQntuples(res);
int nfields = PQnfields(res);
PQclear(res);
ereport(ERROR,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
errmsg("invalid response from primary server"),
errdetail("Could not identify system: got %d rows and %d fields, expected %d rows and %d or more fields.",
ntuples, nfields, 1, 3)));
}
PQntuples(res), PQnfields(res), 1, 3)));
primary_sysid = pstrdup(PQgetvalue(res, 0, 0));
*primary_tli = pg_strtoint32(PQgetvalue(res, 0, 1));
PQclear(res);
@ -607,13 +598,10 @@ libpqrcv_startstreaming(WalReceiverConn *conn,
return false;
}
else if (PQresultStatus(res) != PGRES_COPY_BOTH)
{
PQclear(res);
ereport(ERROR,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
errmsg("could not start WAL streaming: %s",
pchomp(PQerrorMessage(conn->streamConn)))));
}
PQclear(res);
return true;
}
@ -721,26 +709,17 @@ libpqrcv_readtimelinehistoryfile(WalReceiverConn *conn,
cmd,
WAIT_EVENT_LIBPQWALRECEIVER_RECEIVE);
if (PQresultStatus(res) != PGRES_TUPLES_OK)
{
PQclear(res);
ereport(ERROR,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
errmsg("could not receive timeline history file from "
"the primary server: %s",
pchomp(PQerrorMessage(conn->streamConn)))));
}
if (PQnfields(res) != 2 || PQntuples(res) != 1)
{
int ntuples = PQntuples(res);
int nfields = PQnfields(res);
PQclear(res);
ereport(ERROR,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
errmsg("invalid response from primary server"),
errdetail("Expected 1 tuple with 2 fields, got %d tuples with %d fields.",
ntuples, nfields)));
}
PQntuples(res), PQnfields(res))));
*filename = pstrdup(PQgetvalue(res, 0, 0));
*len = PQgetlength(res, 0, 1);
@ -844,13 +823,10 @@ libpqrcv_receive(WalReceiverConn *conn, char **buffer,
return -1;
}
else
{
PQclear(res);
ereport(ERROR,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
errmsg("could not receive data from WAL stream: %s",
pchomp(PQerrorMessage(conn->streamConn)))));
}
}
if (rawlen < -1)
ereport(ERROR,
@ -974,13 +950,10 @@ libpqrcv_create_slot(WalReceiverConn *conn, const char *slotname,
pfree(cmd.data);
if (PQresultStatus(res) != PGRES_TUPLES_OK)
{
PQclear(res);
ereport(ERROR,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
errmsg("could not create replication slot \"%s\": %s",
slotname, pchomp(PQerrorMessage(conn->streamConn)))));
}
if (lsn)
*lsn = DatumGetLSN(DirectFunctionCall1Coll(pg_lsn_in, InvalidOid,

13
src/include/libpq/libpq-be-fe-helpers.h
View File

@ -279,11 +279,8 @@ libpqsrv_exec_params(PGconn *conn,
static inline PGresult *
libpqsrv_get_result_last(PGconn *conn, uint32 wait_event_info)
{
PGresult *volatile lastResult = NULL;
PGresult *lastResult = NULL;
/* In what follows, do not leak any PGresults on an error. */
PG_TRY();
{
for (;;)
{
/* Wait for, and collect, the next PGresult. */
@ -306,14 +303,6 @@ libpqsrv_get_result_last(PGconn *conn, uint32 wait_event_info)
PQstatus(conn) == CONNECTION_BAD)
break;
}
}
PG_CATCH();
{
PQclear(lastResult);
PG_RE_THROW();
}
PG_END_TRY();
return lastResult;
}