diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out b/contrib/postgres_fdw/expected/postgres_fdw.out
index 2390e61c2c..e28cf7722e 100644
--- a/contrib/postgres_fdw/expected/postgres_fdw.out
+++ b/contrib/postgres_fdw/expected/postgres_fdw.out
@@ -3951,3 +3951,63 @@ QUERY: CREATE FOREIGN TABLE t5 (
OPTIONS (schema_name 'import_source', table_name 't5');
CONTEXT: importing foreign table "t5"
ROLLBACK;
+BEGIN;
+CREATE SERVER fetch101 FOREIGN DATA WRAPPER postgres_fdw OPTIONS( fetch_size '101' );
+SELECT count(*)
+FROM pg_foreign_server
+WHERE srvname = 'fetch101'
+AND srvoptions @> array['fetch_size=101'];
+ count
+-------
+ 1
+(1 row)
+
+ALTER SERVER fetch101 OPTIONS( SET fetch_size '202' );
+SELECT count(*)
+FROM pg_foreign_server
+WHERE srvname = 'fetch101'
+AND srvoptions @> array['fetch_size=101'];
+ count
+-------
+ 0
+(1 row)
+
+SELECT count(*)
+FROM pg_foreign_server
+WHERE srvname = 'fetch101'
+AND srvoptions @> array['fetch_size=202'];
+ count
+-------
+ 1
+(1 row)
+
+CREATE FOREIGN TABLE table30000 ( x int ) SERVER fetch101 OPTIONS ( fetch_size '30000' );
+SELECT COUNT(*)
+FROM pg_foreign_table
+WHERE ftrelid = 'table30000'::regclass
+AND ftoptions @> array['fetch_size=30000'];
+ count
+-------
+ 1
+(1 row)
+
+ALTER FOREIGN TABLE table30000 OPTIONS ( SET fetch_size '60000');
+SELECT COUNT(*)
+FROM pg_foreign_table
+WHERE ftrelid = 'table30000'::regclass
+AND ftoptions @> array['fetch_size=30000'];
+ count
+-------
+ 0
+(1 row)
+
+SELECT COUNT(*)
+FROM pg_foreign_table
+WHERE ftrelid = 'table30000'::regclass
+AND ftoptions @> array['fetch_size=60000'];
+ count
+-------
+ 1
+(1 row)
+
+ROLLBACK;
diff --git a/contrib/postgres_fdw/option.c b/contrib/postgres_fdw/option.c
index 86a57890fc..f89de2f694 100644
--- a/contrib/postgres_fdw/option.c
+++ b/contrib/postgres_fdw/option.c
@@ -131,6 +131,17 @@ postgres_fdw_validator(PG_FUNCTION_ARGS)
/* check list syntax, warn about uninstalled extensions */
(void) ExtractExtensionList(defGetString(def), true);
}
+ else if (strcmp(def->defname, "fetch_size") == 0)
+ {
+ int fetch_size;
+
+ fetch_size = strtol(defGetString(def), NULL,10);
+ if (fetch_size <= 0)
+ ereport(ERROR,
+ (errcode(ERRCODE_SYNTAX_ERROR),
+ errmsg("%s requires a non-negative integer value",
+ def->defname)));
+ }
}
PG_RETURN_VOID();
@@ -162,6 +173,9 @@ InitPgFdwOptions(void)
/* updatable is available on both server and table */
{"updatable", ForeignServerRelationId, false},
{"updatable", ForeignTableRelationId, false},
+ /* fetch_size is available on both server and table */
+ {"fetch_size", ForeignServerRelationId, false},
+ {"fetch_size", ForeignTableRelationId, false},
{NULL, InvalidOid, false}
};
diff --git a/contrib/postgres_fdw/postgres_fdw.c b/contrib/postgres_fdw/postgres_fdw.c
index 2ab85f68a7..d5c038335a 100644
--- a/contrib/postgres_fdw/postgres_fdw.c
+++ b/contrib/postgres_fdw/postgres_fdw.c
@@ -68,7 +68,9 @@ enum FdwScanPrivateIndex
/* SQL statement to execute remotely (as a String node) */
FdwScanPrivateSelectSql,
/* Integer list of attribute numbers retrieved by the SELECT */
- FdwScanPrivateRetrievedAttrs
+ FdwScanPrivateRetrievedAttrs,
+ /* Integer representing the desired fetch_size */
+ FdwScanPrivateFetchSize
};
/*
@@ -126,6 +128,8 @@ typedef struct PgFdwScanState
/* working memory contexts */
MemoryContext batch_cxt; /* context holding current batch of tuples */
MemoryContext temp_cxt; /* context for per-tuple temporary data */
+
+ int fetch_size; /* number of tuples per fetch */
} PgFdwScanState;
/*
@@ -380,6 +384,7 @@ postgresGetForeignRelSize(PlannerInfo *root,
fpinfo->fdw_startup_cost = DEFAULT_FDW_STARTUP_COST;
fpinfo->fdw_tuple_cost = DEFAULT_FDW_TUPLE_COST;
fpinfo->shippable_extensions = NIL;
+ fpinfo->fetch_size = 100;
foreach(lc, fpinfo->server->options)
{
@@ -394,16 +399,17 @@ postgresGetForeignRelSize(PlannerInfo *root,
else if (strcmp(def->defname, "extensions") == 0)
fpinfo->shippable_extensions =
ExtractExtensionList(defGetString(def), false);
+ else if (strcmp(def->defname, "fetch_size") == 0)
+ fpinfo->fetch_size = strtol(defGetString(def), NULL,10);
}
foreach(lc, fpinfo->table->options)
{
DefElem *def = (DefElem *) lfirst(lc);
if (strcmp(def->defname, "use_remote_estimate") == 0)
- {
fpinfo->use_remote_estimate = defGetBoolean(def);
- break; /* only need the one value */
- }
+ else if (strcmp(def->defname, "fetch_size") == 0)
+ fpinfo->fetch_size = strtol(defGetString(def), NULL,10);
}
/*
@@ -1012,6 +1018,9 @@ postgresGetForeignPlan(PlannerInfo *root,
*/
fdw_private = list_make2(makeString(sql.data),
retrieved_attrs);
+ fdw_private = list_make3(makeString(sql.data),
+ retrieved_attrs,
+ makeInteger(fpinfo->fetch_size));
/*
* Create the ForeignScan node from target list, filtering expressions,
@@ -1088,6 +1097,8 @@ postgresBeginForeignScan(ForeignScanState *node, int eflags)
FdwScanPrivateSelectSql));
fsstate->retrieved_attrs = (List *) list_nth(fsplan->fdw_private,
FdwScanPrivateRetrievedAttrs);
+ fsstate->fetch_size = intVal(list_nth(fsplan->fdw_private,
+ FdwScanPrivateFetchSize));
/* Create contexts for batches of tuples and per-tuple temp workspace. */
fsstate->batch_cxt = AllocSetContextCreate(estate->es_query_cxt,
@@ -2214,15 +2225,11 @@ fetch_more_data(ForeignScanState *node)
{
PGconn *conn = fsstate->conn;
char sql[64];
- int fetch_size;
int numrows;
int i;
- /* The fetch size is arbitrary, but shouldn't be enormous. */
- fetch_size = 100;
-
snprintf(sql, sizeof(sql), "FETCH %d FROM c%u",
- fetch_size, fsstate->cursor_number);
+ fsstate->fetch_size, fsstate->cursor_number);
res = PQexec(conn, sql);
/* On error, report the original query, not the FETCH. */
@@ -2250,7 +2257,7 @@ fetch_more_data(ForeignScanState *node)
fsstate->fetch_ct_2++;
/* Must be EOF if we didn't get as many tuples as we asked for. */
- fsstate->eof_reached = (numrows < fetch_size);
+ fsstate->eof_reached = (numrows < fsstate->fetch_size);
PQclear(res);
res = NULL;
@@ -2563,6 +2570,7 @@ postgresAcquireSampleRowsFunc(Relation relation, int elevel,
{
PgFdwAnalyzeState astate;
ForeignTable *table;
+ ForeignServer *server;
UserMapping *user;
PGconn *conn;
unsigned int cursor_number;
@@ -2593,6 +2601,7 @@ postgresAcquireSampleRowsFunc(Relation relation, int elevel,
* owner, even if the ANALYZE was started by some other user.
*/
table = GetForeignTable(RelationGetRelid(relation));
+ server = GetForeignServer(table->serverid);
user = GetUserMapping(relation->rd_rel->relowner, table->serverid);
conn = GetConnection(user, false);
@@ -2620,6 +2629,7 @@ postgresAcquireSampleRowsFunc(Relation relation, int elevel,
int fetch_size;
int numrows;
int i;
+ ListCell *lc;
/* Allow users to cancel long query */
CHECK_FOR_INTERRUPTS();
@@ -2632,6 +2642,26 @@ postgresAcquireSampleRowsFunc(Relation relation, int elevel,
/* The fetch size is arbitrary, but shouldn't be enormous. */
fetch_size = 100;
+ foreach(lc, server->options)
+ {
+ DefElem *def = (DefElem *) lfirst(lc);
+
+ if (strcmp(def->defname, "fetch_size") == 0)
+ {
+ fetch_size = strtol(defGetString(def), NULL,10);
+ break;
+ }
+ }
+ foreach(lc, table->options)
+ {
+ DefElem *def = (DefElem *) lfirst(lc);
+
+ if (strcmp(def->defname, "fetch_size") == 0)
+ {
+ fetch_size = strtol(defGetString(def), NULL,10);
+ break;
+ }
+ }
/* Fetch some rows */
snprintf(fetch_sql, sizeof(fetch_sql), "FETCH %d FROM c%u",
diff --git a/contrib/postgres_fdw/postgres_fdw.h b/contrib/postgres_fdw/postgres_fdw.h
index bf83c91481..2b632817fe 100644
--- a/contrib/postgres_fdw/postgres_fdw.h
+++ b/contrib/postgres_fdw/postgres_fdw.h
@@ -53,6 +53,8 @@ typedef struct PgFdwRelationInfo
ForeignTable *table;
ForeignServer *server;
UserMapping *user; /* only set in use_remote_estimate mode */
+
+ int fetch_size; /* fetch size for this remote table */
} PgFdwRelationInfo;
/* in postgres_fdw.c */
diff --git a/contrib/postgres_fdw/sql/postgres_fdw.sql b/contrib/postgres_fdw/sql/postgres_fdw.sql
index 5c6ead1967..ec8a30a3d9 100644
--- a/contrib/postgres_fdw/sql/postgres_fdw.sql
+++ b/contrib/postgres_fdw/sql/postgres_fdw.sql
@@ -919,4 +919,48 @@ BEGIN;
DROP TYPE "Colors" CASCADE;
IMPORT FOREIGN SCHEMA import_source LIMIT TO (t5)
FROM SERVER loopback INTO import_dest5; -- ERROR
+
+ROLLBACK;
+
+BEGIN;
+
+
+CREATE SERVER fetch101 FOREIGN DATA WRAPPER postgres_fdw OPTIONS( fetch_size '101' );
+
+SELECT count(*)
+FROM pg_foreign_server
+WHERE srvname = 'fetch101'
+AND srvoptions @> array['fetch_size=101'];
+
+ALTER SERVER fetch101 OPTIONS( SET fetch_size '202' );
+
+SELECT count(*)
+FROM pg_foreign_server
+WHERE srvname = 'fetch101'
+AND srvoptions @> array['fetch_size=101'];
+
+SELECT count(*)
+FROM pg_foreign_server
+WHERE srvname = 'fetch101'
+AND srvoptions @> array['fetch_size=202'];
+
+CREATE FOREIGN TABLE table30000 ( x int ) SERVER fetch101 OPTIONS ( fetch_size '30000' );
+
+SELECT COUNT(*)
+FROM pg_foreign_table
+WHERE ftrelid = 'table30000'::regclass
+AND ftoptions @> array['fetch_size=30000'];
+
+ALTER FOREIGN TABLE table30000 OPTIONS ( SET fetch_size '60000');
+
+SELECT COUNT(*)
+FROM pg_foreign_table
+WHERE ftrelid = 'table30000'::regclass
+AND ftoptions @> array['fetch_size=30000'];
+
+SELECT COUNT(*)
+FROM pg_foreign_table
+WHERE ftrelid = 'table30000'::regclass
+AND ftoptions @> array['fetch_size=60000'];
+
ROLLBACK;
diff --git a/doc/src/sgml/postgres-fdw.sgml b/doc/src/sgml/postgres-fdw.sgml
index 5a829d537a..a90983cb1e 100644
--- a/doc/src/sgml/postgres-fdw.sgml
+++ b/doc/src/sgml/postgres-fdw.sgml
@@ -290,18 +290,31 @@
be considered shippable to the remote server.
This option can only be specified for foreign servers, not per-table.
+
+
+ When using the extensions option, it is the
+ user's responsibility that the listed extensions exist and behave
+ identically on both the local and remote servers. Otherwise, remote
+ queries may fail or behave unexpectedly.
+
+
+
+
+
+ fetch_size
+
+
+ This option specifies the number of rows postgres_fdw
+ should get in each fetch operation. It can be specified for a foreign
+ table or a foreign server. The option specified on a table overrides
+ an option specified for the server.
+ The default is 100.
+
-
- When using the extensions option, it is the
- user's responsibility that the listed extensions exist and behave
- identically on both the local and remote servers. Otherwise, remote
- queries may fail or behave unexpectedly.
-
-