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oracle_fdw.c
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oracle_fdw.c
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/*-------------------------------------------------------------------------
*
* oracle_fdw.c
* PostgreSQL-related functions for Oracle foreign data wrapper.
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "fmgr.h"
#if PG_VERSION_NUM < 90300
#include "access/htup.h"
#else
#include "access/htup_details.h"
#endif /* PG_VERSION_NUM */
#include "access/reloptions.h"
#include "access/sysattr.h"
#include "access/xact.h"
#include "catalog/indexing.h"
#include "catalog/pg_attribute.h"
#include "catalog/pg_cast.h"
#include "catalog/pg_collation.h"
#include "catalog/pg_foreign_data_wrapper.h"
#include "catalog/pg_foreign_server.h"
#include "catalog/pg_foreign_table.h"
#include "catalog/pg_namespace.h"
#include "catalog/pg_operator.h"
#include "catalog/pg_proc.h"
#include "catalog/pg_user_mapping.h"
#include "catalog/pg_type.h"
#include "commands/explain.h"
#include "commands/vacuum.h"
#include "foreign/fdwapi.h"
#include "foreign/foreign.h"
#include "libpq/md5.h"
#include "mb/pg_wchar.h"
#include "miscadmin.h"
#include "nodes/makefuncs.h"
#include "nodes/nodeFuncs.h"
#include "nodes/pg_list.h"
#include "optimizer/cost.h"
#include "optimizer/pathnode.h"
#include "optimizer/planmain.h"
#include "optimizer/restrictinfo.h"
#include "optimizer/var.h"
#include "parser/parse_relation.h"
#include "parser/parsetree.h"
#include "port.h"
#include "storage/ipc.h"
#include "storage/lock.h"
#include "utils/array.h"
#include "utils/builtins.h"
#include "utils/date.h"
#include "utils/datetime.h"
#include "utils/elog.h"
#include "utils/fmgroids.h"
#include "utils/formatting.h"
#include "utils/guc.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
#include "utils/rel.h"
#include "utils/resowner.h"
#include "utils/timestamp.h"
#include "utils/tqual.h"
#include "utils/snapmgr.h"
#include "utils/syscache.h"
#include "utils/timestamp.h"
#include <string.h>
#include <stdlib.h>
#include "oracle_fdw.h"
/* defined in backend/commands/analyze.c */
#ifndef WIDTH_THRESHOLD
#define WIDTH_THRESHOLD 1024
#endif /* WIDTH_THRESHOLD */
#if PG_VERSION_NUM < 90200
#define OLD_FDW_API
#else
#undef OLD_FDW_API
#endif /* PG_VERSION_NUM */
#if PG_VERSION_NUM >= 90300
#define WRITE_API
#else
#undef WRITE_API
#endif /* PG_VERSION_NUM */
#if PG_VERSION_NUM >= 90500
#define IMPORT_API
/* array_create_iterator has a new signature from 9.5 on */
#define array_create_iterator(arr, slice_ndim) array_create_iterator(arr, slice_ndim, NULL)
#else
#undef IMPORT_API
#endif /* PG_VERSION_NUM */
#if PG_VERSION_NUM >= 90600
/* GetConfigOptionByName has a new signature from 9.6 on */
#define GetConfigOptionByName(name, varname) GetConfigOptionByName(name, varname, false)
#endif /* PG_VERSION_NUM */
PG_MODULE_MAGIC;
/*
* "true" if Oracle data have been modified in the current transaction.
*/
static bool dml_in_transaction = false;
/*
* PostGIS geometry type, set upon library initialization.
*/
static Oid GEOMETRYOID = InvalidOid;
/*
* Describes the valid options for objects that use this wrapper.
*/
struct OracleFdwOption
{
const char *optname;
Oid optcontext; /* Oid of catalog in which option may appear */
bool optrequired;
};
#define OPT_NLS_LANG "nls_lang"
#define OPT_DBSERVER "dbserver"
#define OPT_USER "user"
#define OPT_PASSWORD "password"
#define OPT_SCHEMA "schema"
#define OPT_TABLE "table"
#define OPT_PLAN_COSTS "plan_costs"
#define OPT_MAX_LONG "max_long"
#define OPT_READONLY "readonly"
#define OPT_KEY "key"
#define DEFAULT_MAX_LONG 32767
/*
* Options for case folding for names in IMPORT FOREIGN TABLE.
*/
typedef enum { CASE_KEEP, CASE_LOWER, CASE_SMART } fold_t;
/*
* Valid options for oracle_fdw.
*/
static struct OracleFdwOption valid_options[] = {
{OPT_NLS_LANG, ForeignDataWrapperRelationId, false},
{OPT_DBSERVER, ForeignServerRelationId, true},
{OPT_USER, UserMappingRelationId, true},
{OPT_PASSWORD, UserMappingRelationId, true},
{OPT_SCHEMA, ForeignTableRelationId, false},
{OPT_TABLE, ForeignTableRelationId, true},
{OPT_PLAN_COSTS, ForeignTableRelationId, false},
{OPT_MAX_LONG, ForeignTableRelationId, false},
{OPT_READONLY, ForeignTableRelationId, false}
#ifndef OLD_FDW_API
,{OPT_KEY, AttributeRelationId, false}
#endif /* OLD_FDW_API */
};
#define option_count (sizeof(valid_options)/sizeof(struct OracleFdwOption))
#ifdef WRITE_API
/*
* Array to hold the type output functions during table modification.
* It is ok to hold this cache in a static variable because there cannot
* be more than one foreign table modified at the same time.
*/
static regproc *output_funcs;
#endif /* WRITE_API */
/*
* FDW-specific information for RelOptInfo.fdw_private and ForeignScanState.fdw_state.
* The same structure is used to hold information for query planning and execution.
* The structure is initialized during query planning and passed on to the execution
* step serialized as a List (see serializePlanData and deserializePlanData).
* For DML statements, the scan stage and the modify stage both hold an
* OracleFdwState, and the latter is initialized by copying the former (see copyPlanData).
*/
struct OracleFdwState {
char *dbserver; /* Oracle connect string */
char *user; /* Oracle username */
char *password; /* Oracle password */
char *nls_lang; /* Oracle locale information */
oracleSession *session; /* encapsulates the active Oracle session */
char *query; /* query we issue against Oracle */
List *params; /* list of parameters needed for the query */
struct paramDesc *paramList; /* description of parameters needed for the query */
struct oraTable *oraTable; /* description of the remote Oracle table */
Cost startup_cost; /* cost estimate, only needed for planning */
Cost total_cost; /* cost estimate, only needed for planning */
bool *pushdown_clauses; /* array, true if the corresponding clause can be pushed down */
unsigned long rowcount; /* rows already read from Oracle */
int columnindex; /* currently processed column for error context */
MemoryContext temp_cxt; /* short-lived memory for data modification */
};
/*
* SQL functions
*/
extern PGDLLEXPORT Datum oracle_fdw_handler(PG_FUNCTION_ARGS);
extern PGDLLEXPORT Datum oracle_fdw_validator(PG_FUNCTION_ARGS);
extern PGDLLEXPORT Datum oracle_close_connections(PG_FUNCTION_ARGS);
extern PGDLLEXPORT Datum oracle_diag(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(oracle_fdw_handler);
PG_FUNCTION_INFO_V1(oracle_fdw_validator);
PG_FUNCTION_INFO_V1(oracle_close_connections);
PG_FUNCTION_INFO_V1(oracle_diag);
/*
* on-load initializer
*/
extern PGDLLEXPORT void _PG_init(void);
/*
* FDW callback routines
*/
#ifdef OLD_FDW_API
static FdwPlan *oraclePlanForeignScan(Oid foreigntableid, PlannerInfo *root, RelOptInfo *baserel);
#else
static void oracleGetForeignRelSize(PlannerInfo *root, RelOptInfo *baserel, Oid foreigntableid);
static void oracleGetForeignPaths(PlannerInfo *root, RelOptInfo *baserel, Oid foreigntableid);
static ForeignScan *oracleGetForeignPlan(PlannerInfo *root, RelOptInfo *baserel, Oid foreigntableid, ForeignPath *best_path, List *tlist, List *scan_clauses
#if PG_VERSION_NUM >= 90500
, Plan *outer_plan
#endif /* PG_VERSION_NUM */
);
static bool oracleAnalyzeForeignTable(Relation relation, AcquireSampleRowsFunc *func, BlockNumber *totalpages);
#endif /* OLD_FDW_API */
static void oracleExplainForeignScan(ForeignScanState *node, ExplainState *es);
static void oracleBeginForeignScan(ForeignScanState *node, int eflags);
static TupleTableSlot *oracleIterateForeignScan(ForeignScanState *node);
static void oracleEndForeignScan(ForeignScanState *node);
static void oracleReScanForeignScan(ForeignScanState *node);
#ifdef WRITE_API
static void oracleAddForeignUpdateTargets(Query *parsetree, RangeTblEntry *target_rte, Relation target_relation);
static List *oraclePlanForeignModify(PlannerInfo *root, ModifyTable *plan, Index resultRelation, int subplan_index);
static void oracleBeginForeignModify(ModifyTableState *mtstate, ResultRelInfo *rinfo, List *fdw_private, int subplan_index, int eflags);
static TupleTableSlot *oracleExecForeignInsert(EState *estate, ResultRelInfo *rinfo, TupleTableSlot *slot, TupleTableSlot *planSlot);
static TupleTableSlot *oracleExecForeignUpdate(EState *estate, ResultRelInfo *rinfo, TupleTableSlot *slot, TupleTableSlot *planSlot);
static TupleTableSlot *oracleExecForeignDelete(EState *estate, ResultRelInfo *rinfo, TupleTableSlot *slot, TupleTableSlot *planSlot);
static void oracleEndForeignModify(EState *estate, ResultRelInfo *rinfo);
static void oracleExplainForeignModify(ModifyTableState *mtstate, ResultRelInfo *rinfo, List *fdw_private, int subplan_index, struct ExplainState *es);
static int oracleIsForeignRelUpdatable(Relation rel);
#endif /* WRITE_API */
#ifdef IMPORT_API
static List *oracleImportForeignSchema(ImportForeignSchemaStmt *stmt, Oid serverOid);
#endif /* IMPORT_API */
/*
* Helper functions
*/
static struct OracleFdwState *getFdwState(Oid foreigntableid, bool *plan_costs);
static void oracleGetOptions(Oid foreigntableid, List **options);
static char *createQuery(oracleSession *session, RelOptInfo *foreignrel, bool modify, struct oraTable *oraTable, List **params, bool **pushdown_clauses);
static void getColumnData(Oid foreigntableid, struct oraTable *oraTable);
#ifndef OLD_FDW_API
static int acquireSampleRowsFunc (Relation relation, int elevel, HeapTuple *rows, int targrows, double *totalrows, double *totaldeadrows);
#endif /* OLD_FDW_API */
static char *getOracleWhereClause(oracleSession *session, RelOptInfo *foreignrel, Expr *expr, const struct oraTable *oraTable, List **params);
static char *datumToString(Datum datum, Oid type);
static void getUsedColumns(Expr *expr, struct oraTable *oraTable);
static void checkDataType(oraType oratype, int scale, Oid pgtype, const char *tablename, const char *colname);
static char *guessNlsLang(char *nls_lang);
static List *serializePlanData(struct OracleFdwState *fdwState);
static Const *serializeString(const char *s);
static Const *serializeLong(long i);
static struct OracleFdwState *deserializePlanData(List *list);
static char *deserializeString(Const *constant);
static long deserializeLong(Const *constant);
static bool optionIsTrue(const char *value);
#ifdef WRITE_API
static struct OracleFdwState *copyPlanData(struct OracleFdwState *orig);
static void subtransactionCallback(SubXactEvent event, SubTransactionId mySubid, SubTransactionId parentSubid, void *arg);
static void addParam(struct paramDesc **paramList, char *name, Oid pgtype, oraType oratype, int colnum);
static void setModifyParameters(struct paramDesc *paramList, TupleTableSlot *newslot, TupleTableSlot *oldslot, struct oraTable *oraTable, oracleSession *session);
#endif /* WRITE_API */
static void transactionCallback(XactEvent event, void *arg);
static void exitHook(int code, Datum arg);
static char *setSelectParameters(struct paramDesc *paramList, ExprContext *econtext);
static void convertTuple(struct OracleFdwState *fdw_state, Datum *values, bool *nulls, bool trunc_lob);
static void errorContextCallback(void *arg);
#ifdef IMPORT_API
static char *fold_case(char *name, fold_t foldcase);
#endif /* IMPORT_API */
/*
* Foreign-data wrapper handler function: return a struct with pointers
* to callback routines.
*/
PGDLLEXPORT Datum
oracle_fdw_handler(PG_FUNCTION_ARGS)
{
FdwRoutine *fdwroutine = makeNode(FdwRoutine);
#ifdef OLD_FDW_API
fdwroutine->PlanForeignScan = oraclePlanForeignScan;
#else
fdwroutine->GetForeignRelSize = oracleGetForeignRelSize;
fdwroutine->GetForeignPaths = oracleGetForeignPaths;
fdwroutine->GetForeignPlan = oracleGetForeignPlan;
fdwroutine->AnalyzeForeignTable = oracleAnalyzeForeignTable;
#endif /* OLD_FDW_API */
fdwroutine->ExplainForeignScan = oracleExplainForeignScan;
fdwroutine->BeginForeignScan = oracleBeginForeignScan;
fdwroutine->IterateForeignScan = oracleIterateForeignScan;
fdwroutine->ReScanForeignScan = oracleReScanForeignScan;
fdwroutine->EndForeignScan = oracleEndForeignScan;
#ifdef WRITE_API
fdwroutine->AddForeignUpdateTargets = oracleAddForeignUpdateTargets;
fdwroutine->PlanForeignModify = oraclePlanForeignModify;
fdwroutine->BeginForeignModify = oracleBeginForeignModify;
fdwroutine->ExecForeignInsert = oracleExecForeignInsert;
fdwroutine->ExecForeignUpdate = oracleExecForeignUpdate;
fdwroutine->ExecForeignDelete = oracleExecForeignDelete;
fdwroutine->EndForeignModify = oracleEndForeignModify;
fdwroutine->ExplainForeignModify = oracleExplainForeignModify;
fdwroutine->IsForeignRelUpdatable = oracleIsForeignRelUpdatable;
#endif /* WRITE_API */
#ifdef IMPORT_API
fdwroutine->ImportForeignSchema = oracleImportForeignSchema;
#endif /* IMPORT_API */
PG_RETURN_POINTER(fdwroutine);
}
/*
* oracle_fdw_validator
* Validate the generic options given to a FOREIGN DATA WRAPPER, SERVER,
* USER MAPPING or FOREIGN TABLE that uses oracle_fdw.
*
* Raise an ERROR if the option or its value are considered invalid
* or a required option is missing.
*/
PGDLLEXPORT Datum
oracle_fdw_validator(PG_FUNCTION_ARGS)
{
List *options_list = untransformRelOptions(PG_GETARG_DATUM(0));
Oid catalog = PG_GETARG_OID(1);
ListCell *cell;
bool option_given[option_count] = { false };
int i;
/*
* Check that only options supported by oracle_fdw, and allowed for the
* current object type, are given.
*/
foreach(cell, options_list)
{
DefElem *def = (DefElem *)lfirst(cell);
bool opt_found = false;
/* search for the option in the list of valid options */
for (i=0; i<option_count; ++i)
{
if (catalog == valid_options[i].optcontext && strcmp(valid_options[i].optname, def->defname) == 0)
{
opt_found = true;
option_given[i] = true;
break;
}
}
/* option not found, generate error message */
if (!opt_found)
{
/* generate list of options */
StringInfoData buf;
initStringInfo(&buf);
for (i=0; i<option_count; ++i)
{
if (catalog == valid_options[i].optcontext)
appendStringInfo(&buf, "%s%s", (buf.len > 0) ? ", " : "", valid_options[i].optname);
}
ereport(ERROR,
(errcode(ERRCODE_FDW_INVALID_OPTION_NAME),
errmsg("invalid option \"%s\"", def->defname),
errhint("Valid options in this context are: %s", buf.data)));
}
/* check valid values for plan_costs */
if (strcmp(def->defname, OPT_PLAN_COSTS) == 0
|| strcmp(def->defname, OPT_READONLY) == 0
#ifndef OLD_FDW_API
|| strcmp(def->defname, OPT_KEY) == 0
#endif /* OLD_FDW_API */
)
{
char *val = ((Value *)(def->arg))->val.str;
if (pg_strcasecmp(val, "on") != 0
&& pg_strcasecmp(val, "off") != 0
&& pg_strcasecmp(val, "yes") != 0
&& pg_strcasecmp(val, "no") != 0
&& pg_strcasecmp(val, "true") != 0
&& pg_strcasecmp(val, "false") != 0)
ereport(ERROR,
(errcode(ERRCODE_FDW_INVALID_ATTRIBUTE_VALUE),
errmsg("invalid value for option \"%s\"", def->defname),
errhint("Valid values in this context are: on/yes/true or off/no/false")));
}
/* check valid values for "table" and "schema" */
if (strcmp(def->defname, OPT_TABLE) == 0
|| strcmp(def->defname, OPT_SCHEMA) == 0)
{
char *val = ((Value *)(def->arg))->val.str;
if (strchr(val, '"') != NULL)
ereport(ERROR,
(errcode(ERRCODE_FDW_INVALID_ATTRIBUTE_VALUE),
errmsg("invalid value for option \"%s\"", def->defname),
errhint("Double quotes are not allowed in names.")));
}
/* check valid values for max_long */
if (strcmp(def->defname, OPT_MAX_LONG) == 0)
{
char *val = ((Value *) (def->arg))->val.str;
char *endptr;
unsigned long max_long = strtoul(val, &endptr, 0);
if (val[0] == '\0' || *endptr != '\0' || max_long < 1 || max_long > 1073741823ul)
ereport(ERROR,
(errcode(ERRCODE_FDW_INVALID_ATTRIBUTE_VALUE),
errmsg("invalid value for option \"%s\"", def->defname),
errhint("Valid values in this context are integers between 1 and 1073741823.")));
}
}
/* check that all required options have been given */
for (i=0; i<option_count; ++i)
{
if (catalog == valid_options[i].optcontext && valid_options[i].optrequired && !option_given[i])
{
ereport(ERROR,
(errcode(ERRCODE_FDW_OPTION_NAME_NOT_FOUND),
errmsg("missing required option \"%s\"", valid_options[i].optname)));
}
}
PG_RETURN_VOID();
}
/*
* oracle_close_connections
* Close all open Oracle connections.
*/
PGDLLEXPORT Datum
oracle_close_connections(PG_FUNCTION_ARGS)
{
if (dml_in_transaction)
ereport(ERROR,
(errcode(ERRCODE_ACTIVE_SQL_TRANSACTION),
errmsg("connections with an active transaction cannot be closed"),
errhint("The transaction that modified Oracle data must be closed first.")));
elog(DEBUG1, "oracle_fdw: close all Oracle connections");
oracleCloseConnections();
PG_RETURN_VOID();
}
/*
* oracle_diag
* Get the Oracle client version.
* If a non-NULL argument is supplied, it must be a foreign server name.
* In this case, the remote server version is returned as well.
*/
PGDLLEXPORT Datum
oracle_diag(PG_FUNCTION_ARGS)
{
Oid srvId = InvalidOid;
char *pgversion;
int major, minor, update, patch, port_patch;
StringInfoData version;
/*
* Get the PostgreSQL server version.
* We cannot use PG_VERSION because that would give the version against which
* oracle_fdw was compiled, not the version it is running with.
*/
pgversion = GetConfigOptionByName("server_version", NULL);
/* get the Oracle client version */
oracleClientVersion(&major, &minor, &update, &patch, &port_patch);
initStringInfo(&version);
appendStringInfo(&version, "oracle_fdw %s, PostgreSQL %s, Oracle client %d.%d.%d.%d.%d", ORACLE_FDW_VERSION, pgversion, major, minor, update, patch, port_patch);
if (PG_ARGISNULL(0))
{
/* display some important Oracle environment variables */
static const char * const oracle_env[] = {
"ORACLE_HOME",
"ORACLE_SID",
"TNS_ADMIN",
"TWO_TASK",
"LDAP_ADMIN",
NULL
};
int i;
for (i=0; oracle_env[i] != NULL; ++i)
{
char *val = getenv(oracle_env[i]);
if (val != NULL)
appendStringInfo(&version, ", %s=%s", oracle_env[i], val);
}
}
else
{
/* get the server version only if a non-null argument was given */
HeapTuple tup;
Relation rel;
Name srvname = PG_GETARG_NAME(0);
ForeignServer *server;
UserMapping *mapping;
ForeignDataWrapper *wrapper;
List *options;
ListCell *cell;
char *nls_lang = NULL, *user = NULL, *password = NULL, *dbserver = NULL;
oracleSession *session;
/* look up foreign server with this name */
rel = heap_open(ForeignServerRelationId, AccessShareLock);
tup = SearchSysCacheCopy1(FOREIGNSERVERNAME, NameGetDatum(srvname));
if (!HeapTupleIsValid(tup))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("server \"%s\" does not exist", NameStr(*srvname))));
srvId = HeapTupleGetOid(tup);
heap_close(rel, AccessShareLock);
/* get the foreign server, the user mapping and the FDW */
server = GetForeignServer(srvId);
mapping = GetUserMapping(GetUserId(), srvId);
wrapper = GetForeignDataWrapper(server->fdwid);
/* get all options for these objects */
options = wrapper->options;
options = list_concat(options, server->options);
options = list_concat(options, mapping->options);
foreach(cell, options)
{
DefElem *def = (DefElem *) lfirst(cell);
if (strcmp(def->defname, OPT_NLS_LANG) == 0)
nls_lang = ((Value *) (def->arg))->val.str;
if (strcmp(def->defname, OPT_DBSERVER) == 0)
dbserver = ((Value *) (def->arg))->val.str;
if (strcmp(def->defname, OPT_USER) == 0)
user = ((Value *) (def->arg))->val.str;
if (strcmp(def->defname, OPT_PASSWORD) == 0)
password = ((Value *) (def->arg))->val.str;
}
/* guess a good NLS_LANG environment setting */
nls_lang = guessNlsLang(nls_lang);
/* connect to Oracle database */
session = oracleGetSession(
dbserver,
user,
password,
nls_lang,
NULL,
1
);
/* get the server version */
oracleServerVersion(session, &major, &minor, &update, &patch, &port_patch);
appendStringInfo(&version, ", Oracle server %d.%d.%d.%d.%d", major, minor, update, patch, port_patch);
/* free the session (connection will be cached) */
pfree(session);
}
PG_RETURN_TEXT_P(cstring_to_text(version.data));
}
/*
* _PG_init
* Library load-time initalization.
* Sets exitHook() callback for backend shutdown.
* Also finds the OIDs of PostGIS the PostGIS geometry type.
*/
void
_PG_init(void)
{
Relation proc_rel;
ScanKeyData key;
SysScanDesc scan;
HeapTuple tuple;
/* register an exit hook */
on_proc_exit(&exitHook, PointerGetDatum(NULL));
/* initialize index scan for "st_geomfromwkb" in pg_proc */
proc_rel = heap_open(ProcedureRelationId, AccessShareLock);
ScanKeyInit(&key, Anum_pg_proc_proname, BTEqualStrategyNumber, F_NAMEEQ, CStringGetDatum("st_geomfromwkb"));
scan = systable_beginscan(proc_rel, ProcedureNameArgsNspIndexId, true, GetTransactionSnapshot(), 1, &key);
/* find the first function with two arguments */
while (HeapTupleIsValid(tuple = systable_getnext(scan)))
{
oidvector argtypes;
Form_pg_proc proc_tuple = (Form_pg_proc)GETSTRUCT(tuple);
argtypes = proc_tuple->proargtypes;
if (argtypes.dim1 != 2)
continue;
/*
* If we find two two-argument functions called
* "st_geomfromwkb", assume that two copies of PostGIS
* are installed and give up.
*/
if (GEOMETRYOID != InvalidOid)
{
elog(DEBUG1, "oracle_fdw: more than one PostGIS installation found, giving up");
GEOMETRYOID = InvalidOid;
break;
}
/* the return type must be the PostGIS geometry type */
GEOMETRYOID = proc_tuple->prorettype;
elog(DEBUG1, "oracle_fdw: PostGIS is installed, GEOMETRYOID = %d", GEOMETRYOID);
}
/* end scan */
systable_endscan(scan);
heap_close(proc_rel, AccessShareLock);
}
#ifdef OLD_FDW_API
/*
* oraclePlanForeignScan
* Get an OracleFdwState for this foreign scan.
* A FdwPlan is created and the state is are stored
* ("serialized") in its fdw_private field.
*/
FdwPlan *
oraclePlanForeignScan(Oid foreigntableid,
PlannerInfo *root,
RelOptInfo *baserel)
{
struct OracleFdwState *fdwState;
FdwPlan *fdwplan;
List *fdw_private;
bool plan_costs;
int i;
elog(DEBUG1, "oracle_fdw: plan foreign table scan on %d", foreigntableid);
/* get connection options, connect and get the remote table description */
fdwState = getFdwState(foreigntableid, &plan_costs);
/* construct Oracle query and get the list of parameters and actions for RestrictInfos */
fdwState->query = createQuery(fdwState->session, baserel, false, fdwState->oraTable, &(fdwState->params), &(fdwState->pushdown_clauses));
elog(DEBUG1, "oracle_fdw: remote query is: %s", fdwState->query);
/* get PostgreSQL column data types, check that they match Oracle's */
for (i=0; i<fdwState->oraTable->ncols; ++i)
if (fdwState->oraTable->cols[i]->used)
checkDataType(
fdwState->oraTable->cols[i]->oratype,
fdwState->oraTable->cols[i]->scale,
fdwState->oraTable->cols[i]->pgtype,
fdwState->oraTable->pgname,
fdwState->oraTable->cols[i]->pgname
);
/* get Oracle's (bad) estimate only if plan_costs is set */
if (plan_costs)
{
/* get Oracle's cost estimates for the query */
oracleEstimate(fdwState->session, fdwState->query, seq_page_cost, BLCKSZ, &(fdwState->startup_cost), &(fdwState->total_cost), &baserel->rows, &baserel->width);
}
else
{
/* otherwise, use a random "high" value */
fdwState->startup_cost = fdwState->total_cost = 10000.0;
}
/* release Oracle session (will be cached) */
pfree(fdwState->session);
fdwState->session = NULL;
/* "serialize" all necessary information in the private area */
fdw_private = serializePlanData(fdwState);
/* construct FdwPlan */
fdwplan = makeNode(FdwPlan);
fdwplan->startup_cost = fdwState->startup_cost;
fdwplan->total_cost = fdwState->total_cost;
fdwplan->fdw_private = fdw_private;
return fdwplan;
}
#else
/*
* oracleGetForeignRelSize
* Get an OracleFdwState for this foreign scan.
* Construct the remote SQL query.
* Provide estimates for the number of tuples, the average width and the cost.
*/
void
oracleGetForeignRelSize(PlannerInfo *root, RelOptInfo *baserel, Oid foreigntableid)
{
struct OracleFdwState *fdwState;
bool plan_costs, need_keys = false, for_update = false, has_trigger;
List *local_conditions = NIL;
int i;
double ntuples = -1;
Relation rel;
elog(DEBUG1, "oracle_fdw: plan foreign table scan on %d", foreigntableid);
/* check if the foreign scan is for an UPDATE or DELETE */
if (baserel->relid == root->parse->resultRelation &&
(root->parse->commandType == CMD_UPDATE ||
root->parse->commandType == CMD_DELETE))
{
/* we need the table's primary key columns */
need_keys = true;
}
/* check if FOR [KEY] SHARE/UPDATE was specified */
if (need_keys || get_parse_rowmark(root->parse, baserel->relid))
{
/* we should add FOR UPDATE */
for_update = true;
}
/* get connection options, connect and get the remote table description */
fdwState = getFdwState(foreigntableid, &plan_costs);
if (need_keys)
{
/* we need to fetch all primary key columns */
for (i=0; i<fdwState->oraTable->ncols; ++i)
if (fdwState->oraTable->cols[i]->pkey)
fdwState->oraTable->cols[i]->used = 1;
}
/*
* Core code already has some lock on each rel being planned, so we can
* use NoLock here.
*/
rel = heap_open(foreigntableid, NoLock);
/* is there an AFTER trigger FOR EACH ROW? */
has_trigger = (baserel->relid == root->parse->resultRelation) && rel->trigdesc
&& ((root->parse->commandType == CMD_UPDATE && rel->trigdesc->trig_update_after_row)
|| (root->parse->commandType == CMD_DELETE && rel->trigdesc->trig_delete_after_row));
heap_close(rel, NoLock);
if (has_trigger)
{
/* we need to fetch and return all columns */
for (i=0; i<fdwState->oraTable->ncols; ++i)
if (fdwState->oraTable->cols[i]->pgname)
fdwState->oraTable->cols[i]->used = 1;
}
/* construct Oracle query and get the list of parameters and actions for RestrictInfos */
fdwState->query = createQuery(fdwState->session, baserel, for_update, fdwState->oraTable, &(fdwState->params), &(fdwState->pushdown_clauses));
elog(DEBUG1, "oracle_fdw: remote query is: %s", fdwState->query);
/* get PostgreSQL column data types, check that they match Oracle's */
for (i=0; i<fdwState->oraTable->ncols; ++i)
if (fdwState->oraTable->cols[i]->used)
checkDataType(
fdwState->oraTable->cols[i]->oratype,
fdwState->oraTable->cols[i]->scale,
fdwState->oraTable->cols[i]->pgtype,
fdwState->oraTable->pgname,
fdwState->oraTable->cols[i]->pgname
);
/* get Oracle's (bad) estimate only if plan_costs is set */
if (plan_costs)
{
/* get Oracle's cost estimates for the query */
oracleEstimate(fdwState->session, fdwState->query, seq_page_cost, BLCKSZ, &(fdwState->startup_cost), &(fdwState->total_cost), &ntuples, &baserel->width);
/* estimate selectivity only for conditions that are not pushed down */
for (i=list_length(baserel->baserestrictinfo)-1; i>=0; --i)
if (! fdwState->pushdown_clauses[i])
local_conditions = lcons(list_nth(baserel->baserestrictinfo, i), local_conditions);
}
else
{
/* otherwise, use a random "high" value for cost */
fdwState->startup_cost = 10000.0;
/* if baserel->pages > 0, there was an ANALYZE; use the row count estimate */
if (baserel->pages > 0)
ntuples = baserel->tuples;
/* estimale selectivity locally for all conditions */
local_conditions = baserel->baserestrictinfo;
}
/* release Oracle session (will be cached) */
pfree(fdwState->session);
fdwState->session = NULL;
/* apply statistics only if we have a reasonable row count estimate */
if (ntuples != -1)
{
/* estimate how clauses that are not pushed down will influence row count */
ntuples = ntuples * clauselist_selectivity(root, local_conditions, 0, JOIN_INNER, NULL);
/* make sure that the estimate is not less that 1 */
ntuples = clamp_row_est(ntuples);
baserel->rows = ntuples;
}
/* estimate total cost as startup cost + 10 * (returned rows) */
fdwState->total_cost = fdwState->startup_cost + baserel->rows * 10.0;
/* store the state so that the other planning functions can use it */
baserel->fdw_private = (void *)fdwState;
}
/* oracleGetForeignPaths
* Create a ForeignPath node and add it as only possible path.
*/
void
oracleGetForeignPaths(PlannerInfo *root, RelOptInfo *baserel, Oid foreigntableid)
{
struct OracleFdwState *fdwState = (struct OracleFdwState *)baserel->fdw_private;
add_path(baserel,
(Path *)create_foreignscan_path(root, baserel, baserel->rows,
fdwState->startup_cost, fdwState->total_cost, NIL, NULL,
#if PG_VERSION_NUM >= 90500
NULL, /* no extra plan */
#endif /* PG_VERSION_NUM */
NIL));
}
/*
* oracleGetForeignPlan
* Construct a ForeignScan node containing the serialized OracleFdwState,
* the RestrictInfo clauses not handled entirely by Oracle and the list
* of parameters we need for execution.
*/
ForeignScan
*oracleGetForeignPlan(PlannerInfo *root, RelOptInfo *baserel, Oid foreigntableid, ForeignPath *best_path, List *tlist, List *scan_clauses
#if PG_VERSION_NUM >= 90500
, Plan *outer_plan
#endif /* PG_VERSION_NUM */
)
{
struct OracleFdwState *fdwState = (struct OracleFdwState *)baserel->fdw_private;
List *fdw_private, *keep_clauses = NIL;
ListCell *cell1, *cell2;
int i;
/* "serialize" all necessary information for the path private area */
fdw_private = serializePlanData(fdwState);
/* keep only those clauses that are not handled by Oracle */
foreach(cell1, scan_clauses)
{
i = 0;
foreach(cell2, baserel->baserestrictinfo)
{
if (equal(lfirst(cell1), lfirst(cell2)) && ! fdwState->pushdown_clauses[i])
{
keep_clauses = lcons(lfirst(cell1), keep_clauses);
break;
}
++i;
}
}
/* remove the RestrictInfo node from all remaining clauses */
keep_clauses = extract_actual_clauses(keep_clauses, false);
/* Create the ForeignScan node */
return make_foreignscan(tlist, keep_clauses, baserel->relid, fdwState->params, fdw_private
#if PG_VERSION_NUM >= 90500
, NIL,
NIL, /* no parameterized paths */
outer_plan
#endif /* PG_VERSION_NUM */
);
}
bool
oracleAnalyzeForeignTable(Relation relation, AcquireSampleRowsFunc *func, BlockNumber *totalpages)
{
*func = acquireSampleRowsFunc;
/* use positive page count as a sign that the table has been ANALYZEd */
*totalpages = 42;
return true;
}
#endif /* OLD_FDW_API */
/*
* oracleExplainForeignScan
* Produce extra output for EXPLAIN:
* the Oracle query and, if VERBOSE was given, the execution plan.
*/
void
oracleExplainForeignScan(ForeignScanState *node, ExplainState *es)
{
struct OracleFdwState *fdw_state = (struct OracleFdwState *)node->fdw_state;
char **plan;
int nrows, i;
elog(DEBUG1, "oracle_fdw: explain foreign table scan on %d", RelationGetRelid(node->ss.ss_currentRelation));
/* show query */
ExplainPropertyText("Oracle query", fdw_state->query, es);
if (es->verbose)
{
/* get the EXPLAIN PLAN */
oracleExplain(fdw_state->session, fdw_state->query, &nrows, &plan);
/* add it to explain text */
for (i=0; i<nrows; ++i)
{
ExplainPropertyText("Oracle plan", plan[i], es);
}
}
}
/*
* oracleBeginForeignScan
* Recover ("deserialize") connection information, remote query,
* Oracle table description and parameter list from the plan's
* "fdw_private" field.
* Reestablish a connection to Oracle.
*/
void
oracleBeginForeignScan(ForeignScanState *node, int eflags)
{
ForeignScan *fsplan = (ForeignScan *)node->ss.ps.plan;
#ifdef OLD_FDW_API
List *fdw_private = ((FdwPlan *)fsplan->fdwplan)->fdw_private;
#else
List *fdw_private = fsplan->fdw_private;
List *exec_exprs;
ListCell *cell;
int index;
#endif /* OLD_FDW_API */
struct paramDesc *paramDesc;
struct OracleFdwState *fdw_state;
/* deserialize private plan data */
fdw_state = deserializePlanData(fdw_private);
node->fdw_state = (void *)fdw_state;
#ifndef OLD_FDW_API
/* create an ExprState tree for the parameter expressions */
exec_exprs = (List *)ExecInitExpr((Expr *)fsplan->fdw_exprs, (PlanState *)node);
/* create the list of parameters */
index = 0;
foreach(cell, exec_exprs)
{
ExprState *expr = (ExprState *)lfirst(cell);
char parname[10];
/* count, but skip deleted entries */
++index;
if (expr == NULL)
continue;
/* create a new entry in the parameter list */
paramDesc = (struct paramDesc *)palloc(sizeof(struct paramDesc));
snprintf(parname, 10, ":p%d", index);
paramDesc->name = pstrdup(parname);
paramDesc->type = exprType((Node *)(expr->expr));
if (paramDesc->type == TEXTOID || paramDesc->type == VARCHAROID
|| paramDesc->type == BPCHAROID || paramDesc->type == CHAROID)
paramDesc->bindType = BIND_STRING;
else if (paramDesc->type == DATEOID || paramDesc->type == TIMESTAMPOID
|| paramDesc->type == TIMESTAMPTZOID)
paramDesc->bindType = BIND_TIMESTAMP;
else
paramDesc->bindType = BIND_NUMBER;