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mongo_fdw.c
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/*-------------------------------------------------------------------------
*
* mongo_fdw.c
* Foreign-data wrapper for remote MongoDB servers
*
* Portions Copyright (c) 2012-2014, PostgreSQL Global Development Group
* Portions Copyright (c) 2004-2021, EnterpriseDB Corporation.
* Portions Copyright (c) 2012–2014 Citus Data, Inc.
*
* IDENTIFICATION
* mongo_fdw.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "mongo_wrapper.h"
#if PG_VERSION_NUM >= 90300
#include "access/htup_details.h"
#endif
#if PG_VERSION_NUM < 120000
#include "access/sysattr.h"
#endif
#if PG_VERSION_NUM >= 120000
#include "access/table.h"
#endif
#include "catalog/heap.h"
#include "catalog/pg_type.h"
#if PG_VERSION_NUM >= 130000
#include "common/hashfn.h"
#include "common/jsonapi.h"
#endif
#include "miscadmin.h"
#include "mongo_fdw.h"
#include "mongo_query.h"
#if PG_VERSION_NUM >= 140000
#include "optimizer/appendinfo.h"
#endif
#if PG_VERSION_NUM >= 120000
#include "optimizer/optimizer.h"
#endif
#if PG_VERSION_NUM < 120000
#include "optimizer/var.h"
#endif
#include "parser/parsetree.h"
#include "storage/ipc.h"
#include "utils/jsonb.h"
#if PG_VERSION_NUM < 130000
#include "utils/jsonapi.h"
#else
#include "utils/jsonfuncs.h"
#endif
#include "utils/rel.h"
/* Declarations for dynamic loading */
PG_MODULE_MAGIC;
/*
* In PG 9.5.1 the number will be 90501,
* our version is 5.2.10 so number will be 50210
*/
#define CODE_VERSION 50210
extern PGDLLEXPORT void _PG_init(void);
const char *EscapeJsonString(const char *string);
void BsonToJsonString(StringInfo output, BSON_ITERATOR iter, bool isArray);
PG_FUNCTION_INFO_V1(mongo_fdw_handler);
PG_FUNCTION_INFO_V1(mongo_fdw_version);
/* FDW callback routines */
static void MongoGetForeignRelSize(PlannerInfo *root,
RelOptInfo *baserel,
Oid foreigntableid);
static void MongoGetForeignPaths(PlannerInfo *root,
RelOptInfo *baserel,
Oid foreigntableid);
static ForeignScan *MongoGetForeignPlan(PlannerInfo *root,
RelOptInfo *foreignrel,
Oid foreigntableid,
ForeignPath *best_path,
List *targetlist,
List *restrictionClauses,
Plan *outer_plan);
static void MongoExplainForeignScan(ForeignScanState *node, ExplainState *es);
static void MongoBeginForeignScan(ForeignScanState *node, int eflags);
static TupleTableSlot *MongoIterateForeignScan(ForeignScanState *node);
static void MongoEndForeignScan(ForeignScanState *node);
static void MongoReScanForeignScan(ForeignScanState *node);
static TupleTableSlot *MongoExecForeignUpdate(EState *estate,
ResultRelInfo *resultRelInfo,
TupleTableSlot *slot,
TupleTableSlot *planSlot);
static TupleTableSlot *MongoExecForeignDelete(EState *estate,
ResultRelInfo *resultRelInfo,
TupleTableSlot *slot,
TupleTableSlot *planSlot);
static void MongoEndForeignModify(EState *estate,
ResultRelInfo *resultRelInfo);
#if PG_VERSION_NUM >= 140000
static void MongoAddForeignUpdateTargets(PlannerInfo *root,
Index rtindex,
RangeTblEntry *target_rte,
Relation target_relation);
#else
static void MongoAddForeignUpdateTargets(Query *parsetree,
RangeTblEntry *target_rte,
Relation target_relation);
#endif
static void MongoBeginForeignModify(ModifyTableState *mtstate,
ResultRelInfo *resultRelInfo,
List *fdw_private,
int subplan_index,
int eflags);
static TupleTableSlot *MongoExecForeignInsert(EState *estate,
ResultRelInfo *resultRelInfo,
TupleTableSlot *slot,
TupleTableSlot *planSlot);
static List *MongoPlanForeignModify(PlannerInfo *root,
ModifyTable *plan,
Index resultRelation,
int subplan_index);
static void MongoExplainForeignModify(ModifyTableState *mtstate,
ResultRelInfo *rinfo,
List *fdw_private,
int subplan_index,
ExplainState *es);
static bool MongoAnalyzeForeignTable(Relation relation,
AcquireSampleRowsFunc *func,
BlockNumber *totalpages);
#if PG_VERSION_NUM >= 110000
static void MongoBeginForeignInsert(ModifyTableState *mtstate,
ResultRelInfo *resultRelInfo);
static void MongoEndForeignInsert(EState *estate,
ResultRelInfo *resultRelInfo);
#endif
/*
* Helper functions
*/
static double ForeignTableDocumentCount(Oid foreignTableId);
static HTAB *ColumnMappingHash(Oid foreignTableId, List *columnList);
static void FillTupleSlot(const BSON *bsonDocument,
const char *bsonDocumentKey,
HTAB *columnMappingHash,
Datum *columnValues,
bool *columnNulls);
static bool ColumnTypesCompatible(BSON_TYPE bsonType, Oid columnTypeId);
static Datum ColumnValueArray(BSON_ITERATOR *bsonIterator, Oid valueTypeId);
static Datum ColumnValue(BSON_ITERATOR *bsonIterator,
Oid columnTypeId,
int32 columnTypeMod);
static void MongoFreeScanState(MongoFdwModifyState *fmstate);
static int MongoAcquireSampleRows(Relation relation,
int errorLevel,
HeapTuple *sampleRows,
int targetRowCount,
double *totalRowCount,
double *totalDeadRowCount);
static void mongo_fdw_exit(int code, Datum arg);
/* The null action object used for pure validation */
#if PG_VERSION_NUM < 130000
static JsonSemAction nullSemAction =
{
NULL, NULL, NULL, NULL, NULL,
NULL, NULL, NULL, NULL, NULL
};
#else
JsonSemAction nullSemAction =
{
NULL, NULL, NULL, NULL, NULL,
NULL, NULL, NULL, NULL, NULL
};
#endif
/*
* Library load-time initalization, sets on_proc_exit() callback for
* backend shutdown.
*/
void
_PG_init(void)
{
#ifdef META_DRIVER
/* Initialize MongoDB C driver */
mongoc_init();
#endif
on_proc_exit(&mongo_fdw_exit, PointerGetDatum(NULL));
}
/*
* mongo_fdw_handler
* Creates and returns a struct with pointers to foreign table callback
* functions.
*/
Datum
mongo_fdw_handler(PG_FUNCTION_ARGS)
{
FdwRoutine *fdwRoutine = makeNode(FdwRoutine);
/* Functions for scanning foreign tables */
fdwRoutine->GetForeignRelSize = MongoGetForeignRelSize;
fdwRoutine->GetForeignPaths = MongoGetForeignPaths;
fdwRoutine->GetForeignPlan = MongoGetForeignPlan;
fdwRoutine->BeginForeignScan = MongoBeginForeignScan;
fdwRoutine->IterateForeignScan = MongoIterateForeignScan;
fdwRoutine->ReScanForeignScan = MongoReScanForeignScan;
fdwRoutine->EndForeignScan = MongoEndForeignScan;
/* Support for insert/update/delete */
fdwRoutine->AddForeignUpdateTargets = MongoAddForeignUpdateTargets;
fdwRoutine->PlanForeignModify = MongoPlanForeignModify;
fdwRoutine->BeginForeignModify = MongoBeginForeignModify;
fdwRoutine->ExecForeignInsert = MongoExecForeignInsert;
fdwRoutine->ExecForeignUpdate = MongoExecForeignUpdate;
fdwRoutine->ExecForeignDelete = MongoExecForeignDelete;
fdwRoutine->EndForeignModify = MongoEndForeignModify;
/* Support for EXPLAIN */
fdwRoutine->ExplainForeignScan = MongoExplainForeignScan;
fdwRoutine->ExplainForeignModify = MongoExplainForeignModify;
/* Support for ANALYZE */
fdwRoutine->AnalyzeForeignTable = MongoAnalyzeForeignTable;
#if PG_VERSION_NUM >= 110000
/* Partition routing and/or COPY from */
fdwRoutine->BeginForeignInsert = MongoBeginForeignInsert;
fdwRoutine->EndForeignInsert = MongoEndForeignInsert;
#endif
PG_RETURN_POINTER(fdwRoutine);
}
/*
* mongo_fdw_exit
* Exit callback function.
*/
static void
mongo_fdw_exit(int code, Datum arg)
{
mongo_cleanup_connection();
#ifdef META_DRIVER
/* Release all memory and other resources allocated by the driver */
mongoc_cleanup();
#endif
}
/*
* MongoGetForeignRelSize
* Obtains relation size estimates for mongo foreign table.
*/
static void
MongoGetForeignRelSize(PlannerInfo *root,
RelOptInfo *baserel,
Oid foreigntableid)
{
double documentCount = ForeignTableDocumentCount(foreigntableid);
MongoFdwRelationInfo *fpinfo;
ListCell *lc;
/*
* We use MongoFdwRelationInfo to pass various information to subsequent
* functions.
*/
fpinfo = (MongoFdwRelationInfo *) palloc0(sizeof(MongoFdwRelationInfo));
baserel->fdw_private = (void *) fpinfo;
/*
* Identify which baserestrictinfo clauses can be sent to the remote
* server and which can't. Only the OpExpr clauses are sent to the remote
* server.
*/
foreach(lc, baserel->baserestrictinfo)
{
RestrictInfo *ri = (RestrictInfo *) lfirst(lc);
if (IsA(ri->clause, OpExpr) &&
mongo_is_foreign_expr(root, baserel, ri->clause))
fpinfo->remote_conds = lappend(fpinfo->remote_conds, ri);
else
fpinfo->local_conds = lappend(fpinfo->local_conds, ri);
}
if (documentCount > 0.0)
{
double rowSelectivity;
/*
* We estimate the number of rows returned after restriction
* qualifiers are applied. This will be more accurate if analyze is
* run on this relation.
*/
rowSelectivity = clauselist_selectivity(root,
baserel->baserestrictinfo,
0, JOIN_INNER, NULL);
baserel->rows = clamp_row_est(documentCount * rowSelectivity);
}
else
ereport(DEBUG1,
(errmsg("could not retrieve document count for collection"),
errhint("Falling back to default estimates in planning.")));
}
/*
* MongoGetForeignPaths
* Creates the only scan path used to execute the query.
*
* Note that MongoDB may decide to use an underlying index for this scan, but
* that decision isn't deterministic or visible to us. We therefore create a
* single table scan path.
*/
static void
MongoGetForeignPaths(PlannerInfo *root,
RelOptInfo *baserel,
Oid foreigntableid)
{
double tupleFilterCost = baserel->baserestrictcost.per_tuple;
double inputRowCount;
double documentSelectivity;
double foreignTableSize;
int32 documentWidth;
BlockNumber pageCount;
double totalDiskAccessCost;
double cpuCostPerDoc;
double cpuCostPerRow;
double totalCpuCost;
double connectionCost;
double documentCount;
List *opExpressionList;
Cost startupCost = 0.0;
Cost totalCost = 0.0;
Path *foreignPath;
MongoFdwRelationInfo *fpinfo = (MongoFdwRelationInfo *) baserel->fdw_private;
documentCount = ForeignTableDocumentCount(foreigntableid);
if (documentCount > 0.0)
{
/*
* We estimate the number of rows returned after restriction
* qualifiers are applied by MongoDB.
*/
opExpressionList = fpinfo->remote_conds;
documentSelectivity = clauselist_selectivity(root, opExpressionList,
0, JOIN_INNER, NULL);
inputRowCount = clamp_row_est(documentCount * documentSelectivity);
/*
* We estimate disk costs assuming a sequential scan over the data.
* This is an inaccurate assumption as Mongo scatters the data over
* disk pages, and may rely on an index to retrieve the data. Still,
* this should at least give us a relative cost.
*/
documentWidth = get_relation_data_width(foreigntableid,
baserel->attr_widths);
foreignTableSize = documentCount * documentWidth;
pageCount = (BlockNumber) rint(foreignTableSize / BLCKSZ);
totalDiskAccessCost = seq_page_cost * pageCount;
/*
* The cost of processing a document returned by Mongo (input row) is
* 5x the cost of processing a regular row.
*/
cpuCostPerDoc = cpu_tuple_cost;
cpuCostPerRow = (cpu_tuple_cost * MONGO_TUPLE_COST_MULTIPLIER) + tupleFilterCost;
totalCpuCost = (cpuCostPerDoc * documentCount) +(cpuCostPerRow * inputRowCount);
connectionCost = MONGO_CONNECTION_COST_MULTIPLIER * seq_page_cost;
startupCost = baserel->baserestrictcost.startup + connectionCost;
totalCost = startupCost + totalDiskAccessCost + totalCpuCost;
}
else
ereport(DEBUG1,
(errmsg("could not retrieve document count for collection"),
errhint("Falling back to default estimates in planning.")));
/* Create a foreign path node */
foreignPath = (Path *) create_foreignscan_path(root, baserel,
#if PG_VERSION_NUM >= 90600
NULL, /* default pathtarget */
#endif
baserel->rows,
startupCost,
totalCost,
NIL, /* no pathkeys */
baserel->lateral_relids,
#if PG_VERSION_NUM >= 90500
NULL, /* no extra plan */
#endif
NULL); /* no fdw_private data */
/* Add foreign path as the only possible path */
add_path(baserel, foreignPath);
}
/*
* MongoGetForeignPlan
* Creates a foreign scan plan node for scanning the MongoDB collection.
*
* Note that MongoDB may decide to use an underlying index for this
* scan, but that decision isn't deterministic or visible to us.
*/
static ForeignScan *
MongoGetForeignPlan(PlannerInfo *root,
RelOptInfo *foreignrel,
Oid foreigntableid,
ForeignPath *best_path,
List *targetList,
List *restrictionClauses,
Plan *outer_plan)
{
MongoFdwRelationInfo *fpinfo = (MongoFdwRelationInfo *) foreignrel->fdw_private;
Index scanRangeTableIndex = foreignrel->relid;
ForeignScan *foreignScan;
List *foreignPrivateList;
List *columnList;
List *scan_var_list;
ListCell *lc;
List *local_exprs = NIL;
List *remote_exprs = NIL;
#if PG_VERSION_NUM >= 90600
scan_var_list = pull_var_clause((Node *) foreignrel->reltarget->exprs,
PVC_RECURSE_PLACEHOLDERS);
#else
scan_var_list = pull_var_clause((Node *) foreignrel->reltargetlist,
PVC_RECURSE_AGGREGATES,
PVC_RECURSE_PLACEHOLDERS);
#endif
/* System attributes are not allowed. */
foreach(lc, scan_var_list)
{
Var *var = lfirst(lc);
const FormData_pg_attribute *attr;
Assert(IsA(var, Var));
if (var->varattno >= 0)
continue;
#if PG_VERSION_NUM >= 120000
attr = SystemAttributeDefinition(var->varattno);
#else
attr = SystemAttributeDefinition(var->varattno, false);
#endif
ereport(ERROR,
(errcode(ERRCODE_FDW_COLUMN_NAME_NOT_FOUND),
errmsg("system attribute \"%s\" can't be fetched from remote relation",
attr->attname.data)));
}
/*
* Separate the restrictionClauses into those that can be executed remotely
* and those that can't. baserestrictinfo clauses that were previously
* determined to be safe or unsafe are shown in fpinfo->remote_conds and
* fpinfo->local_conds. Anything else in the restrictionClauses list will
* be a join clause, which we have to check for remote-safety. Only the
* OpExpr clauses are sent to the remote server.
*/
foreach(lc, restrictionClauses)
{
RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
Assert(IsA(rinfo, RestrictInfo));
/* Ignore pseudoconstants, they are dealt with elsewhere */
if (rinfo->pseudoconstant)
continue;
if (list_member_ptr(fpinfo->remote_conds, rinfo))
remote_exprs = lappend(remote_exprs, rinfo->clause);
else if (list_member_ptr(fpinfo->local_conds, rinfo))
local_exprs = lappend(local_exprs, rinfo->clause);
else if (IsA(rinfo->clause, OpExpr) &&
mongo_is_foreign_expr(root, foreignrel, rinfo->clause))
remote_exprs = lappend(remote_exprs, rinfo->clause);
else
local_exprs = lappend(local_exprs, rinfo->clause);
}
/* Add local expression Var nodes to scan_var_list. */
scan_var_list = list_concat_unique(NIL, scan_var_list);
scan_var_list = list_concat_unique(scan_var_list,
pull_var_clause((Node *) local_exprs,
PVC_RECURSE_PLACEHOLDERS));
/* Form column list required for query execution from scan_var_list. */
columnList = mongo_get_column_list(root, foreignrel, scan_var_list);
/* Construct foreign plan with query document and column list */
foreignPrivateList = list_make2(columnList, remote_exprs);
/* Create the foreign scan node */
foreignScan = make_foreignscan(targetList, local_exprs,
scanRangeTableIndex,
NIL, /* No expressions to evaluate */
foreignPrivateList
#if PG_VERSION_NUM >= 90500
,NIL
,NIL
,NULL
#endif
);
return foreignScan;
}
/*
* MongoExplainForeignScan
* Produces extra output for the Explain command.
*/
static void
MongoExplainForeignScan(ForeignScanState *node, ExplainState *es)
{
MongoFdwOptions *options;
StringInfo namespaceName;
Oid foreignTableId;
foreignTableId = RelationGetRelid(node->ss.ss_currentRelation);
options = mongo_get_options(foreignTableId);
/* Construct fully qualified collection name */
namespaceName = makeStringInfo();
appendStringInfo(namespaceName, "%s.%s", options->svr_database,
options->collectionName);
mongo_free_options(options);
ExplainPropertyText("Foreign Namespace", namespaceName->data, es);
}
static void
MongoExplainForeignModify(ModifyTableState *mtstate,
ResultRelInfo *rinfo,
List *fdw_private,
int subplan_index,
ExplainState *es)
{
MongoFdwOptions *options;
StringInfo namespaceName;
Oid foreignTableId;
foreignTableId = RelationGetRelid(rinfo->ri_RelationDesc);
options = mongo_get_options(foreignTableId);
/* Construct fully qualified collection name */
namespaceName = makeStringInfo();
appendStringInfo(namespaceName, "%s.%s", options->svr_database,
options->collectionName);
mongo_free_options(options);
ExplainPropertyText("Foreign Namespace", namespaceName->data, es);
}
/*
* MongoBeginForeignScan
* Connects to the MongoDB server, and opens a cursor that uses the
* database name, collection name, and the remote query to send to the
* server.
*
* The function also creates a hash table that maps referenced
* column names to column index and type information.
*/
static void
MongoBeginForeignScan(ForeignScanState *node, int eflags)
{
MONGO_CONN *mongoConnection;
Oid foreignTableId;
List *columnList;
HTAB *columnMappingHash;
List *foreignPrivateList;
MongoFdwOptions *options;
MongoFdwModifyState *fmstate;
RangeTblEntry *rte;
EState *estate = node->ss.ps.state;
ForeignScan *fsplan = (ForeignScan *) node->ss.ps.plan;
Oid userid;
ForeignServer *server;
UserMapping *user;
ForeignTable *table;
/* If Explain with no Analyze, do nothing */
if (eflags & EXEC_FLAG_EXPLAIN_ONLY)
return;
foreignTableId = RelationGetRelid(node->ss.ss_currentRelation);
options = mongo_get_options(foreignTableId);
fmstate = (MongoFdwModifyState *) palloc0(sizeof(MongoFdwModifyState));
/*
* Identify which user to do the remote access as. This should match what
* ExecCheckRTEPerms() does.
*/
rte = rt_fetch(fsplan->scan.scanrelid, estate->es_range_table);
userid = rte->checkAsUser ? rte->checkAsUser : GetUserId();
/* Get info about foreign table. */
fmstate->rel = node->ss.ss_currentRelation;
table = GetForeignTable(RelationGetRelid(fmstate->rel));
server = GetForeignServer(table->serverid);
user = GetUserMapping(userid, server->serverid);
/*
* Get connection to the foreign server. Connection manager will establish
* new connection if necessary.
*/
mongoConnection = mongo_get_connection(server, user, options);
foreignPrivateList = fsplan->fdw_private;
Assert(list_length(foreignPrivateList) == 2);
columnList = list_nth(foreignPrivateList, 0);
columnMappingHash = ColumnMappingHash(foreignTableId, columnList);
/* Create and set foreign execution state */
fmstate->columnMappingHash = columnMappingHash;
fmstate->mongoConnection = mongoConnection;
fmstate->options = options;
node->fdw_state = (void *) fmstate;
}
/*
* MongoIterateForeignScan
* Opens a Mongo cursor that uses the database name, collection name, and
* the remote query to send to the server.
*
* Reads the next document from MongoDB, converts it to a PostgreSQL tuple,
* and stores the converted tuple into the ScanTupleSlot as a virtual tuple.
*/
static TupleTableSlot *
MongoIterateForeignScan(ForeignScanState *node)
{
MongoFdwModifyState *fmstate = (MongoFdwModifyState *) node->fdw_state;
TupleTableSlot *tupleSlot = node->ss.ss_ScanTupleSlot;
MONGO_CURSOR *mongoCursor = fmstate->mongoCursor;
HTAB *columnMappingHash = fmstate->columnMappingHash;
ForeignScan *foreignScan = (ForeignScan *) node->ss.ps.plan;
TupleDesc tupleDescriptor = tupleSlot->tts_tupleDescriptor;
Datum *columnValues = tupleSlot->tts_values;
bool *columnNulls = tupleSlot->tts_isnull;
int32 columnCount = tupleDescriptor->natts;
/* Create cursor for collection name and set query */
if (mongoCursor == NULL)
{
Oid foreignTableId;
List *foreignPrivateList;
List *opExpressionList;
BSON *queryDocument;
foreignPrivateList = foreignScan->fdw_private;
Assert(list_length(foreignPrivateList) == 2);
opExpressionList = list_nth(foreignPrivateList, 1);
foreignTableId = RelationGetRelid(node->ss.ss_currentRelation);
/*
* We construct the query document to have MongoDB filter its rows. We
* could also construct a column name document here to retrieve only
* the needed columns. However, we found this optimization to degrade
* performance on the MongoDB server-side, so we instead filter out
* columns on our side.
*/
queryDocument = QueryDocument(foreignTableId, opExpressionList, node);
mongoCursor = MongoCursorCreate(fmstate->mongoConnection,
fmstate->options->svr_database,
fmstate->options->collectionName,
queryDocument);
/* Save mongoCursor */
fmstate->mongoCursor = mongoCursor;
}
/*
* We execute the protocol to load a virtual tuple into a slot. We first
* call ExecClearTuple, then fill in values / isnull arrays, and last call
* ExecStoreVirtualTuple. If we are done fetching documents from Mongo,
* we just return an empty slot as required.
*/
ExecClearTuple(tupleSlot);
/* Initialize all values for this row to null */
memset(columnValues, 0, columnCount * sizeof(Datum));
memset(columnNulls, true, columnCount * sizeof(bool));
if (MongoCursorNext(mongoCursor, NULL))
{
const BSON *bsonDocument = MongoCursorBson(mongoCursor);
const char *bsonDocumentKey = NULL; /* Top level document */
FillTupleSlot(bsonDocument, bsonDocumentKey, columnMappingHash,
columnValues, columnNulls);
ExecStoreVirtualTuple(tupleSlot);
}
return tupleSlot;
}
/*
* MongoEndForeignScan
* Finishes scanning the foreign table, closes the cursor and the
* connection to MongoDB, and reclaims scan related resources.
*/
static void
MongoEndForeignScan(ForeignScanState *node)
{
MongoFdwModifyState *fmstate;
fmstate = (MongoFdwModifyState *) node->fdw_state;
/* If we executed a query, reclaim mongo related resources */
if (fmstate != NULL)
{
if (fmstate->options)
{
mongo_free_options(fmstate->options);
fmstate->options = NULL;
}
MongoFreeScanState(fmstate);
}
}
/*
* MongoReScanForeignScan
* Rescans the foreign table.
*
* Note that rescans in Mongo end up being notably more expensive than what the
* planner expects them to be, since MongoDB cursors don't provide reset/rewind
* functionality.
*/
static void
MongoReScanForeignScan(ForeignScanState *node)
{
MongoFdwModifyState *fmstate = (MongoFdwModifyState *) node->fdw_state;
/* Close down the old cursor */
if (fmstate->mongoCursor)
{
MongoCursorDestroy(fmstate->mongoCursor);
fmstate->mongoCursor = NULL;
}
}
static List *
MongoPlanForeignModify(PlannerInfo *root,
ModifyTable *plan,
Index resultRelation,
int subplan_index)
{
CmdType operation = plan->operation;
RangeTblEntry *rte = planner_rt_fetch(resultRelation, root);
Relation rel;
List *targetAttrs = NIL;
/*
* Core code already has some lock on each rel being planned, so we can
* use NoLock here.
*/
#if PG_VERSION_NUM < 130000
rel = heap_open(rte->relid, NoLock);
#else
rel = table_open(rte->relid, NoLock);
#endif
if (operation == CMD_INSERT)
{
TupleDesc tupdesc = RelationGetDescr(rel);
int attnum;
for (attnum = 1; attnum <= tupdesc->natts; attnum++)
{
#if PG_VERSION_NUM < 110000
Form_pg_attribute attr = tupdesc->attrs[attnum - 1];
#else
Form_pg_attribute attr = TupleDescAttr(tupdesc, attnum - 1);
#endif
if (!attr->attisdropped)
targetAttrs = lappend_int(targetAttrs, attnum);
}
}
else if (operation == CMD_UPDATE)
{
#if PG_VERSION_NUM >= 90500
Bitmapset *tmpset = bms_copy(rte->updatedCols);
#else
Bitmapset *tmpset = bms_copy(rte->modifiedCols);
#endif
AttrNumber col;
while ((col = bms_first_member(tmpset)) >= 0)
{
col += FirstLowInvalidHeapAttributeNumber;
if (col <= InvalidAttrNumber) /* Shouldn't happen */
elog(ERROR, "system-column update is not supported");
/*
* We also disallow updates to the first column which happens to
* be the row identifier in MongoDb (_id)
*/
if (col == 1) /* Shouldn't happen */
elog(ERROR, "row identifier column update is not supported");
targetAttrs = lappend_int(targetAttrs, col);
}
/* We also want the rowid column to be available for the update */
targetAttrs = lcons_int(1, targetAttrs);
}
else
targetAttrs = lcons_int(1, targetAttrs);
/*
* RETURNING list not supported
*/
if (plan->returningLists)
elog(ERROR, "RETURNING is not supported by this FDW");
#if PG_VERSION_NUM < 130000
heap_close(rel, NoLock);
#else
table_close(rel, NoLock);
#endif
return list_make1(targetAttrs);
}
/*
* MongoBeginForeignModify
* Begin an insert/update/delete operation on a foreign table.
*/
static void
MongoBeginForeignModify(ModifyTableState *mtstate,
ResultRelInfo *resultRelInfo,
List *fdw_private,
int subplan_index,
int eflags)
{
MongoFdwModifyState *fmstate;
Relation rel = resultRelInfo->ri_RelationDesc;
AttrNumber n_params;
Oid typefnoid = InvalidOid;
bool isvarlena = false;
ListCell *lc;
Oid foreignTableId;
Oid userid;
ForeignServer *server;
UserMapping *user;
ForeignTable *table;
/*
* Do nothing in EXPLAIN (no ANALYZE) case. resultRelInfo->ri_FdwState
* stays NULL.
*/
if (eflags & EXEC_FLAG_EXPLAIN_ONLY)
return;
foreignTableId = RelationGetRelid(rel);
userid = GetUserId();
/* Get info about foreign table. */
table = GetForeignTable(foreignTableId);
server = GetForeignServer(table->serverid);
user = GetUserMapping(userid, server->serverid);
/* Begin constructing MongoFdwModifyState. */
fmstate = (MongoFdwModifyState *) palloc0(sizeof(MongoFdwModifyState));
fmstate->rel = rel;
fmstate->options = mongo_get_options(foreignTableId);
/*
* Get connection to the foreign server. Connection manager will
* establish new connection if necessary.
*/
fmstate->mongoConnection = mongo_get_connection(server, user,
fmstate->options);
fmstate->target_attrs = (List *) list_nth(fdw_private, 0);
n_params = list_length(fmstate->target_attrs) + 1;
fmstate->p_flinfo = (FmgrInfo *) palloc(sizeof(FmgrInfo) * n_params);
fmstate->p_nums = 0;
if (mtstate->operation == CMD_UPDATE)
{
Form_pg_attribute attr;
#if PG_VERSION_NUM >= 140000
Plan *subplan = outerPlanState(mtstate)->plan;
#else
Plan *subplan = mtstate->mt_plans[subplan_index]->plan;
#endif
Assert(subplan != NULL);
attr = TupleDescAttr(RelationGetDescr(rel), 0);
/* Find the rowid resjunk column in the subplan's result */
fmstate->rowidAttno = ExecFindJunkAttributeInTlist(subplan->targetlist,
NameStr(attr->attname));
if (!AttributeNumberIsValid(fmstate->rowidAttno))
elog(ERROR, "could not find junk row identifier column");
}
/* Set up for remaining transmittable parameters */
foreach(lc, fmstate->target_attrs)
{
int attnum = lfirst_int(lc);
#if PG_VERSION_NUM < 110000
Form_pg_attribute attr = RelationGetDescr(rel)->attrs[attnum - 1];
#else
Form_pg_attribute attr = TupleDescAttr(RelationGetDescr(rel),
attnum - 1);
#endif
Assert(!attr->attisdropped);
getTypeOutputInfo(attr->atttypid, &typefnoid, &isvarlena);
fmgr_info(typefnoid, &fmstate->p_flinfo[fmstate->p_nums]);
fmstate->p_nums++;
}
Assert(fmstate->p_nums <= n_params);
resultRelInfo->ri_FdwState = fmstate;
}
/*
* MongoExecForeignInsert
* Insert one row into a foreign table.
*/
static TupleTableSlot *
MongoExecForeignInsert(EState *estate,
ResultRelInfo *resultRelInfo,
TupleTableSlot *slot,
TupleTableSlot *planSlot)
{
BSON *bsonDoc;
Oid typoid;
Datum value;
bool isnull = false;
MongoFdwModifyState *fmstate;
fmstate = (MongoFdwModifyState *) resultRelInfo->ri_FdwState;
bsonDoc = BsonCreate();
typoid = get_atttype(RelationGetRelid(resultRelInfo->ri_RelationDesc), 1);
/* Get following parameters from slot */
if (slot != NULL && fmstate->target_attrs != NIL)
{
ListCell *lc;
foreach(lc, fmstate->target_attrs)
{
int attnum = lfirst_int(lc);
value = slot_getattr(slot, attnum, &isnull);
/* First column of MongoDB's foreign table must be _id */
#if PG_VERSION_NUM < 110000
if (strcmp(slot->tts_tupleDescriptor->attrs[0]->attname.data, "_id") != 0)
#else
if (strcmp(TupleDescAttr(slot->tts_tupleDescriptor, 0)->attname.data, "_id") != 0)
#endif
elog(ERROR, "first column of MongoDB's foreign table must be \"_id\"");
if (typoid != NAMEOID)
elog(ERROR, "type of first column of MongoDB's foreign table must be \"NAME\"");
#if PG_VERSION_NUM < 110000
if (strcmp(slot->tts_tupleDescriptor->attrs[0]->attname.data, "__doc") == 0)
#else
if (strcmp(TupleDescAttr(slot->tts_tupleDescriptor, 0)->attname.data, "__doc") == 0)
#endif
continue;
/*
* Ignore the value of first column which is row identifier in
* MongoDb (_id) and let MongoDB to insert the unique value for
* that column.
*/
if (attnum == 1)
continue;
#if PG_VERSION_NUM < 110000
AppendMongoValue(bsonDoc,
slot->tts_tupleDescriptor->attrs[attnum - 1]->attname.data,
value,
isnull,
slot->tts_tupleDescriptor->attrs[attnum - 1]->atttypid);
#else
AppendMongoValue(bsonDoc,
TupleDescAttr(slot->tts_tupleDescriptor, attnum - 1)->attname.data,
value,