mirror of
https://github.com/postgres/postgres.git
synced 2025-07-27 12:41:57 +03:00
Attached is a patch that replaces a bunch of places where StringInfos
are unnecessarily allocated on the heap rather than the stack. If the StringInfo doesn't outlive the stack frame in which it is created, there is no need to allocate it on the heap via makeStringInfo() -- stack allocation is faster. While it's not a big deal unless the code is in a critical path, I don't see a reason not to save a few cycles -- using stack allocation is not less readable. I also cleaned up a bit of code along the way: moved variable declarations into a more tightly-enclosing scope where possible, fixed some pointless copying of strings in dblink, etc.
This commit is contained in:
Neil Conway
@ -301,11 +301,12 @@ dblink_open(PG_FUNCTION_ARGS)
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char *curname = NULL;
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char *sql = NULL;
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char *conname = NULL;
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StringInfo str = makeStringInfo();
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StringInfoData buf;
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remoteConn *rconn = NULL;
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bool fail = true; /* default to backward compatible behavior */
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DBLINK_INIT;
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initStringInfo(&buf);
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if (PG_NARGS() == 2)
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{
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@ -361,8 +362,8 @@ dblink_open(PG_FUNCTION_ARGS)
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if (rconn->newXactForCursor)
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(rconn->openCursorCount)++;
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appendStringInfo(str, "DECLARE %s CURSOR FOR %s", curname, sql);
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res = PQexec(conn, str->data);
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appendStringInfo(&buf, "DECLARE %s CURSOR FOR %s", curname, sql);
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res = PQexec(conn, buf.data);
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if (!res || PQresultStatus(res) != PGRES_COMMAND_OK)
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{
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if (fail)
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@ -389,12 +390,13 @@ dblink_close(PG_FUNCTION_ARGS)
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PGresult *res = NULL;
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char *curname = NULL;
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char *conname = NULL;
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StringInfo str = makeStringInfo();
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StringInfoData buf;
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char *msg;
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remoteConn *rconn = NULL;
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bool fail = true; /* default to backward compatible behavior */
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DBLINK_INIT;
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initStringInfo(&buf);
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if (PG_NARGS() == 1)
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{
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@ -432,10 +434,10 @@ dblink_close(PG_FUNCTION_ARGS)
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else
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conn = rconn->conn;
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appendStringInfo(str, "CLOSE %s", curname);
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appendStringInfo(&buf, "CLOSE %s", curname);
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/* close the cursor */
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res = PQexec(conn, str->data);
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res = PQexec(conn, buf.data);
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if (!res || PQresultStatus(res) != PGRES_COMMAND_OK)
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{
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if (fail)
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@ -493,7 +495,7 @@ dblink_fetch(PG_FUNCTION_ARGS)
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if (SRF_IS_FIRSTCALL())
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{
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PGconn *conn = NULL;
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StringInfo str = makeStringInfo();
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StringInfoData buf;
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char *curname = NULL;
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int howmany = 0;
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bool fail = true; /* default to backward compatible */
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@ -542,6 +544,9 @@ dblink_fetch(PG_FUNCTION_ARGS)
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if (!conn)
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DBLINK_CONN_NOT_AVAIL;
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initStringInfo(&buf);
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appendStringInfo(&buf, "FETCH %d FROM %s", howmany, curname);
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/* create a function context for cross-call persistence */
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funcctx = SRF_FIRSTCALL_INIT();
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@ -550,9 +555,7 @@ dblink_fetch(PG_FUNCTION_ARGS)
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*/
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oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
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appendStringInfo(str, "FETCH %d FROM %s", howmany, curname);
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res = PQexec(conn, str->data);
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res = PQexec(conn, buf.data);
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if (!res ||
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(PQresultStatus(res) != PGRES_COMMAND_OK &&
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PQresultStatus(res) != PGRES_TUPLES_OK))
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@ -1547,13 +1550,14 @@ get_sql_insert(Oid relid, int2vector *pkattnums, int16 pknumatts, char **src_pka
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HeapTuple tuple;
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TupleDesc tupdesc;
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int natts;
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StringInfo str = makeStringInfo();
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char *sql;
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StringInfoData buf;
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char *val;
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int16 key;
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int i;
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bool needComma;
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initStringInfo(&buf);
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/* get relation name including any needed schema prefix and quoting */
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relname = generate_relation_name(relid);
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@ -1570,7 +1574,7 @@ get_sql_insert(Oid relid, int2vector *pkattnums, int16 pknumatts, char **src_pka
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(errcode(ERRCODE_CARDINALITY_VIOLATION),
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errmsg("source row not found")));
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appendStringInfo(str, "INSERT INTO %s(", relname);
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appendStringInfo(&buf, "INSERT INTO %s(", relname);
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needComma = false;
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for (i = 0; i < natts; i++)
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@ -1579,14 +1583,14 @@ get_sql_insert(Oid relid, int2vector *pkattnums, int16 pknumatts, char **src_pka
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continue;
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if (needComma)
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appendStringInfo(str, ",");
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appendStringInfo(&buf, ",");
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appendStringInfo(str, "%s",
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appendStringInfoString(&buf,
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quote_ident_cstr(NameStr(tupdesc->attrs[i]->attname)));
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needComma = true;
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}
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appendStringInfo(str, ") VALUES(");
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appendStringInfo(&buf, ") VALUES(");
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/*
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* remember attvals are 1 based
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@ -1598,7 +1602,7 @@ get_sql_insert(Oid relid, int2vector *pkattnums, int16 pknumatts, char **src_pka
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continue;
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if (needComma)
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appendStringInfo(str, ",");
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appendStringInfo(&buf, ",");
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if (tgt_pkattvals != NULL)
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key = get_attnum_pk_pos(pkattnums, pknumatts, i + 1);
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@ -1612,21 +1616,17 @@ get_sql_insert(Oid relid, int2vector *pkattnums, int16 pknumatts, char **src_pka
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if (val != NULL)
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{
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appendStringInfo(str, "%s", quote_literal_cstr(val));
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appendStringInfoString(&buf, quote_literal_cstr(val));
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pfree(val);
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}
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else
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appendStringInfo(str, "NULL");
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appendStringInfo(&buf, "NULL");
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needComma = true;
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}
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appendStringInfo(str, ")");
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appendStringInfo(&buf, ")");
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sql = pstrdup(str->data);
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pfree(str->data);
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pfree(str);
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relation_close(rel, AccessShareLock);
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return (sql);
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return (buf.data);
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}
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static char *
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@ -1636,10 +1636,11 @@ get_sql_delete(Oid relid, int2vector *pkattnums, int16 pknumatts, char **tgt_pka
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char *relname;
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TupleDesc tupdesc;
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int natts;
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StringInfo str = makeStringInfo();
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char *sql;
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StringInfoData buf;
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int i;
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initStringInfo(&buf);
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/* get relation name including any needed schema prefix and quoting */
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relname = generate_relation_name(relid);
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@ -1650,15 +1651,15 @@ get_sql_delete(Oid relid, int2vector *pkattnums, int16 pknumatts, char **tgt_pka
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tupdesc = rel->rd_att;
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natts = tupdesc->natts;
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appendStringInfo(str, "DELETE FROM %s WHERE ", relname);
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appendStringInfo(&buf, "DELETE FROM %s WHERE ", relname);
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for (i = 0; i < pknumatts; i++)
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{
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int16 pkattnum = pkattnums->values[i];
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if (i > 0)
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appendStringInfo(str, " AND ");
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appendStringInfo(&buf, " AND ");
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appendStringInfo(str, "%s",
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appendStringInfoString(&buf,
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quote_ident_cstr(NameStr(tupdesc->attrs[pkattnum - 1]->attname)));
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if (tgt_pkattvals == NULL)
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@ -1666,18 +1667,14 @@ get_sql_delete(Oid relid, int2vector *pkattnums, int16 pknumatts, char **tgt_pka
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elog(ERROR, "target key array must not be NULL");
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if (tgt_pkattvals[i] != NULL)
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appendStringInfo(str, " = %s",
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appendStringInfo(&buf, " = %s",
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quote_literal_cstr(tgt_pkattvals[i]));
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else
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appendStringInfo(str, " IS NULL");
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appendStringInfo(&buf, " IS NULL");
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}
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sql = pstrdup(str->data);
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pfree(str->data);
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pfree(str);
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relation_close(rel, AccessShareLock);
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return (sql);
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return (buf.data);
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}
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static char *
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@ -1688,13 +1685,14 @@ get_sql_update(Oid relid, int2vector *pkattnums, int16 pknumatts, char **src_pka
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HeapTuple tuple;
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TupleDesc tupdesc;
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int natts;
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StringInfo str = makeStringInfo();
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char *sql;
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StringInfoData buf;
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char *val;
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int16 key;
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int i;
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bool needComma;
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initStringInfo(&buf);
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/* get relation name including any needed schema prefix and quoting */
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relname = generate_relation_name(relid);
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@ -1711,7 +1709,7 @@ get_sql_update(Oid relid, int2vector *pkattnums, int16 pknumatts, char **src_pka
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(errcode(ERRCODE_CARDINALITY_VIOLATION),
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errmsg("source row not found")));
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appendStringInfo(str, "UPDATE %s SET ", relname);
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appendStringInfo(&buf, "UPDATE %s SET ", relname);
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needComma = false;
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for (i = 0; i < natts; i++)
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@ -1720,9 +1718,9 @@ get_sql_update(Oid relid, int2vector *pkattnums, int16 pknumatts, char **src_pka
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continue;
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if (needComma)
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appendStringInfo(str, ", ");
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appendStringInfo(&buf, ", ");
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appendStringInfo(str, "%s = ",
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appendStringInfo(&buf, "%s = ",
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quote_ident_cstr(NameStr(tupdesc->attrs[i]->attname)));
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if (tgt_pkattvals != NULL)
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@ -1737,24 +1735,24 @@ get_sql_update(Oid relid, int2vector *pkattnums, int16 pknumatts, char **src_pka
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if (val != NULL)
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{
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appendStringInfo(str, "%s", quote_literal_cstr(val));
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appendStringInfoString(&buf, quote_literal_cstr(val));
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pfree(val);
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}
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else
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appendStringInfo(str, "NULL");
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appendStringInfoString(&buf, "NULL");
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needComma = true;
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}
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appendStringInfo(str, " WHERE ");
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appendStringInfo(&buf, " WHERE ");
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for (i = 0; i < pknumatts; i++)
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{
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int16 pkattnum = pkattnums->values[i];
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if (i > 0)
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appendStringInfo(str, " AND ");
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appendStringInfo(&buf, " AND ");
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appendStringInfo(str, "%s",
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appendStringInfo(&buf, "%s",
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quote_ident_cstr(NameStr(tupdesc->attrs[pkattnum - 1]->attname)));
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if (tgt_pkattvals != NULL)
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@ -1764,19 +1762,15 @@ get_sql_update(Oid relid, int2vector *pkattnums, int16 pknumatts, char **src_pka
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if (val != NULL)
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{
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appendStringInfo(str, " = %s", quote_literal_cstr(val));
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appendStringInfo(&buf, " = %s", quote_literal_cstr(val));
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pfree(val);
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}
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else
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appendStringInfo(str, " IS NULL");
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appendStringInfo(&buf, " IS NULL");
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}
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sql = pstrdup(str->data);
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pfree(str->data);
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pfree(str);
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relation_close(rel, AccessShareLock);
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return (sql);
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return (buf.data);
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}
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/*
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@ -1836,12 +1830,13 @@ get_tuple_of_interest(Oid relid, int2vector *pkattnums, int16 pknumatts, char **
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Relation rel;
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char *relname;
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TupleDesc tupdesc;
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StringInfo str = makeStringInfo();
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char *sql = NULL;
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StringInfoData buf;
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int ret;
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HeapTuple tuple;
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int i;
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initStringInfo(&buf);
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/* get relation name including any needed schema prefix and quoting */
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relname = generate_relation_name(relid);
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@ -1863,34 +1858,30 @@ get_tuple_of_interest(Oid relid, int2vector *pkattnums, int16 pknumatts, char **
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* Build sql statement to look up tuple of interest Use src_pkattvals as
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* the criteria.
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*/
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appendStringInfo(str, "SELECT * FROM %s WHERE ", relname);
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appendStringInfo(&buf, "SELECT * FROM %s WHERE ", relname);
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for (i = 0; i < pknumatts; i++)
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{
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int16 pkattnum = pkattnums->values[i];
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if (i > 0)
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appendStringInfo(str, " AND ");
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appendStringInfo(&buf, " AND ");
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appendStringInfo(str, "%s",
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appendStringInfoString(&buf,
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quote_ident_cstr(NameStr(tupdesc->attrs[pkattnum - 1]->attname)));
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if (src_pkattvals[i] != NULL)
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appendStringInfo(str, " = %s",
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appendStringInfo(&buf, " = %s",
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quote_literal_cstr(src_pkattvals[i]));
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else
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appendStringInfo(str, " IS NULL");
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appendStringInfo(&buf, " IS NULL");
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}
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sql = pstrdup(str->data);
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pfree(str->data);
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pfree(str);
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/*
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* Retrieve the desired tuple
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*/
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ret = SPI_exec(sql, 0);
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pfree(sql);
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ret = SPI_exec(buf.data, 0);
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pfree(buf.data);
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/*
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* Only allow one qualifying tuple
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