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mongo_fdw.c
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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) 2004-2014, EnterpriseDB Corporation.
*
* Portions Copyright (c) 2012–2014 Citus Data, Inc.
*
* IDENTIFICATION
* mongo_fdw.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "bson.h"
#include "mongo_wrapper.h"
#include "mongo_fdw.h"
#include "mongo_query.h"
#include "access/reloptions.h"
#include "catalog/pg_type.h"
#include "commands/defrem.h"
#include "commands/explain.h"
#include "commands/vacuum.h"
#include "foreign/fdwapi.h"
#include "foreign/foreign.h"
#include "nodes/makefuncs.h"
#include "optimizer/cost.h"
#include "optimizer/pathnode.h"
#include "optimizer/plancat.h"
#include "optimizer/planmain.h"
#include "optimizer/restrictinfo.h"
#include "storage/ipc.h"
#include "utils/array.h"
#include "utils/builtins.h"
#include "utils/date.h"
#include "utils/hsearch.h"
#include "utils/lsyscache.h"
#include "utils/rel.h"
#include "utils/memutils.h"
#include "access/sysattr.h"
#include "commands/defrem.h"
#include "commands/explain.h"
#include "commands/vacuum.h"
#include "foreign/fdwapi.h"
#include "funcapi.h"
#include "miscadmin.h"
#include "nodes/makefuncs.h"
#include "nodes/nodeFuncs.h"
#include "optimizer/cost.h"
#include "optimizer/pathnode.h"
#include "optimizer/paths.h"
#include "optimizer/planmain.h"
#include "optimizer/prep.h"
#include "optimizer/restrictinfo.h"
#include "optimizer/var.h"
#include "parser/parsetree.h"
#include "utils/builtins.h"
#include "utils/guc.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
#include "utils/jsonapi.h"
#include "utils/jsonb.h"
#if PG_VERSION_NUM >= 90300
#include "access/htup_details.h"
#endif
/* Local functions forward declarations */
static void MongoGetForeignRelSize(PlannerInfo *root, RelOptInfo *baserel,
Oid foreignTableId);
static void MongoGetForeignPaths(PlannerInfo *root, RelOptInfo *baserel,
Oid foreignTableId);
static ForeignScan *
MongoGetForeignPlan(PlannerInfo *root,
RelOptInfo *baserel,
Oid foreigntableid,
ForeignPath *best_path,
List *targetlist,
List *restrictionClauses,
Plan *outer_plan);
static void MongoExplainForeignScan(ForeignScanState *scanState,
ExplainState *explainState);
static void MongoBeginForeignScan(ForeignScanState *scanState, int executorFlags);
static TupleTableSlot * MongoIterateForeignScan(ForeignScanState *scanState);
static void MongoEndForeignScan(ForeignScanState *scanState);
static void MongoReScanForeignScan(ForeignScanState *scanState);
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);
static void MongoAddForeignUpdateTargets(Query *parsetree,
RangeTblEntry *target_rte,
Relation target_relation);
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);
/* local 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 bool MongoAnalyzeForeignTable(Relation relation,
AcquireSampleRowsFunc *acquireSampleRowsFunc,
BlockNumber *totalPageCount);
static int MongoAcquireSampleRows(Relation relation, int errorLevel,
HeapTuple *sampleRows, int targetRowCount,
double *totalRowCount, double *totalDeadRowCount);
static void mongo_fdw_exit(int code, Datum arg);
extern PGDLLEXPORT void _PG_init(void);
const char * EscapeJsonString(const char *string);
void BsonToJsonString(StringInfo output, BSON_ITERATOR iter, bool isArray);
/* the null action object used for pure validation */
static JsonSemAction nullSemAction =
{
NULL, NULL, NULL, NULL, NULL,
NULL, NULL, NULL, NULL, NULL
};
/* declarations for dynamic loading */
PG_MODULE_MAGIC;
PG_FUNCTION_INFO_V1(mongo_fdw_handler);
/*
* Library load-time initalization, sets on_proc_exit() callback for
* backend shutdown.
*/
void
_PG_init(void)
{
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);
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->ExecForeignInsert = MongoExecForeignInsert;
fdwRoutine->BeginForeignModify = MongoBeginForeignModify;
fdwRoutine->PlanForeignModify = MongoPlanForeignModify;
fdwRoutine->AddForeignUpdateTargets = MongoAddForeignUpdateTargets;
fdwRoutine->ExecForeignUpdate = MongoExecForeignUpdate;
fdwRoutine->ExecForeignDelete = MongoExecForeignDelete;
fdwRoutine->EndForeignModify = MongoEndForeignModify;
/* support for EXPLAIN */
fdwRoutine->ExplainForeignScan = MongoExplainForeignScan;
fdwRoutine->ExplainForeignModify = MongoExplainForeignModify;
/* support for ANALYSE */
fdwRoutine->AnalyzeForeignTable = MongoAnalyzeForeignTable;
PG_RETURN_POINTER(fdwRoutine);
}
/*
* Exit callback function.
*/
static void
mongo_fdw_exit(int code, Datum arg)
{
mongo_cleanup_connection();
}
/*
* MongoGetForeignRelSize obtains relation size estimates for mongo foreign table.
*/
static void
MongoGetForeignRelSize(PlannerInfo *root, RelOptInfo *baserel, Oid foreignTableId)
{
double documentCount = ForeignTableDocumentCount(foreignTableId);
if (documentCount > 0.0)
{
/*
* We estimate the number of rows returned after restriction qualifiers
* are applied. This will be more accurate if analyze is run on this
* relation.
*/
List *rowClauseList = baserel->baserestrictinfo;
double rowSelectivity = clauselist_selectivity(root, rowClauseList,
0, JOIN_INNER, NULL);
double outputRowCount = clamp_row_est(documentCount * rowSelectivity);
baserel->rows = outputRowCount;
}
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 = 0.0;
double documentSelectivity = 0.0;
double foreignTableSize = 0;
int32 documentWidth = 0;
BlockNumber pageCount = 0;
double totalDiskAccessCost = 0.0;
double cpuCostPerDoc = 0.0;
double cpuCostPerRow = 0.0;
double totalCpuCost = 0.0;
double connectionCost = 0.0;
double documentCount = 0.0;
List *opExpressionList = NIL;
Cost startupCost = 0.0;
Cost totalCost = 0.0;
Path *foreignPath = NULL;
documentCount = ForeignTableDocumentCount(foreignTableId);
if (documentCount > 0.0)
{
/*
* We estimate the number of rows returned after restriction qualifiers
* are applied by MongoDB.
*/
opExpressionList = ApplicableOpExpressionList(baserel);
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 */
NULL, /* no outer rel either */
#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 *baserel,
Oid foreigntableid,
ForeignPath *best_path,
List *targetList,
List *restrictionClauses,
Plan *outer_plan)
{
Index scanRangeTableIndex = baserel->relid;
ForeignScan *foreignScan = NULL;
List *foreignPrivateList = NIL;
List *opExpressionList = NIL;
BSON *queryDocument = NULL;
List *columnList = NIL;
/*
* We push down applicable restriction clauses to MongoDB, but for simplicity
* we currently put all the restrictionClauses into the plan node's qual
* list for the executor to re-check. So all we have to do here is strip
* RestrictInfo nodes from the clauses and ignore pseudoconstants (which
* will be handled elsewhere).
*/
restrictionClauses = extract_actual_clauses(restrictionClauses, false);
/*
* 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.
*/
opExpressionList = ApplicableOpExpressionList(baserel);
queryDocument = QueryDocument(foreigntableid, opExpressionList, NULL);
/* we don't need to serialize column list as lists are copiable */
columnList = ColumnList(baserel);
/* construct foreign plan with query document and column list */
foreignPrivateList = list_make2(columnList, opExpressionList);
/* only clean up the query struct */
BsonDestroy(queryDocument);
/* create the foreign scan node */
foreignScan = make_foreignscan(targetList, restrictionClauses,
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 *scanState, ExplainState *explainState)
{
MongoFdwOptions *options = NULL;
StringInfo namespaceName = NULL;
Oid foreignTableId = InvalidOid;
foreignTableId = RelationGetRelid(scanState->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, explainState);
}
static void
MongoExplainForeignModify(ModifyTableState *mtstate,
ResultRelInfo *rinfo,
List *fdw_private,
int subplan_index,
ExplainState *es)
{
MongoFdwOptions *options = NULL;
StringInfo namespaceName = NULL;
Oid foreignTableId = InvalidOid;
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 *scanState, int executorFlags)
{
MONGO_CONN *mongoConnection = NULL;
MONGO_CURSOR *mongoCursor = NULL;
Oid foreignTableId = InvalidOid;
List *columnList = NIL;
HTAB *columnMappingHash = NULL;
ForeignScan *foreignScan = NULL;
List *foreignPrivateList = NIL;
BSON *queryDocument = NULL;
MongoFdwOptions *options = NULL;
MongoFdwModifyState *fmstate = NULL;
List *opExpressionList = NIL;
RangeTblEntry *rte;
EState *estate = scanState->ss.ps.state;
ForeignScan *fsplan = (ForeignScan *) scanState->ss.ps.plan;
Oid userid;
ForeignServer *server;
UserMapping *user;
ForeignTable *table;
/* if Explain with no Analyze, do nothing */
if (executorFlags & EXEC_FLAG_EXPLAIN_ONLY)
return;
foreignTableId = RelationGetRelid(scanState->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 = scanState->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);
foreignScan = (ForeignScan *) scanState->ss.ps.plan;
foreignPrivateList = foreignScan->fdw_private;
Assert(list_length(foreignPrivateList) == 2);
columnList = list_nth(foreignPrivateList, 0);
opExpressionList = list_nth(foreignPrivateList, 1);
queryDocument = QueryDocument(foreignTableId, opExpressionList, scanState);
columnMappingHash = ColumnMappingHash(foreignTableId, columnList);
/* create cursor for collection name and set query */
mongoCursor = MongoCursorCreate(mongoConnection, options->svr_database, options->collectionName, queryDocument);
/* create and set foreign execution state */
fmstate->columnMappingHash = columnMappingHash;
fmstate->mongoConnection = mongoConnection;
fmstate->mongoCursor = mongoCursor;
fmstate->queryDocument = queryDocument;
fmstate->options = options;
scanState->fdw_state = (void *) fmstate;
}
/*
* MongoIterateForeignScan 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 *scanState)
{
MongoFdwModifyState *fmstate = (MongoFdwModifyState *) scanState->fdw_state;
TupleTableSlot *tupleSlot = scanState->ss.ss_ScanTupleSlot;
MONGO_CURSOR *mongoCursor = fmstate->mongoCursor;
HTAB *columnMappingHash = fmstate->columnMappingHash;
TupleDesc tupleDescriptor = tupleSlot->tts_tupleDescriptor;
Datum *columnValues = tupleSlot->tts_values;
bool *columnNulls = tupleSlot->tts_isnull;
int32 columnCount = tupleDescriptor->natts;
/*
* 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 *scanState)
{
MongoFdwModifyState *fmstate = (MongoFdwModifyState *) scanState->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 *scanState)
{
MongoFdwModifyState *fmstate = (MongoFdwModifyState *) scanState->fdw_state;
MONGO_CONN *mongoConnection = fmstate->mongoConnection;
MongoFdwOptions *options = NULL;
Oid foreignTableId = InvalidOid;
/* close down the old cursor */
MongoCursorDestroy(fmstate->mongoCursor);
/* reconstruct full collection name */
foreignTableId = RelationGetRelid(scanState->ss.ss_currentRelation);
options = mongo_get_options(foreignTableId);
/* reconstruct cursor for collection name and set query */
fmstate->mongoCursor = MongoCursorCreate(mongoConnection,
fmstate->options->svr_database,
fmstate->options->collectionName,
fmstate->queryDocument);
mongo_free_options(options);
}
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.
*/
rel = heap_open(rte->relid, NoLock);
if (operation == CMD_INSERT)
{
TupleDesc tupdesc = RelationGetDescr(rel);
int attnum;
for (attnum = 1; attnum <= tupdesc->natts; attnum++)
{
Form_pg_attribute attr = tupdesc->attrs[attnum - 1];
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");
heap_close(rel, NoLock);
return list_make1(targetAttrs);
}
/*
* 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 = NULL;
Relation rel = resultRelInfo->ri_RelationDesc;
AttrNumber n_params = 0;
Oid typefnoid = InvalidOid;
bool isvarlena = false;
ListCell *lc = NULL;
Oid foreignTableId = InvalidOid;
/*
* Do nothing in EXPLAIN (no ANALYZE) case. resultRelInfo->ri_FdwState
* stays NULL.
*/
if (eflags & EXEC_FLAG_EXPLAIN_ONLY)
return;
foreignTableId = RelationGetRelid(rel);
/* Begin constructing MongoFdwModifyState. */
fmstate = (MongoFdwModifyState *) palloc0(sizeof(MongoFdwModifyState));
fmstate->rel = rel;
fmstate->options = mongo_get_options(foreignTableId);
fmstate->target_attrs = (List *) list_nth(fdw_private, 0);
n_params = list_length(fmstate->target_attrs) + 1;
fmstate->p_flinfo = (FmgrInfo *) palloc0(sizeof(FmgrInfo) * n_params);
fmstate->p_nums = 0;
/* Set up for remaining transmittable parameters */
foreach(lc, fmstate->target_attrs)
{
int attnum = lfirst_int(lc);
Form_pg_attribute attr = RelationGetDescr(rel)->attrs[attnum - 1];
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;
}
/*
* Insert one row into a foreign table.
*/
static TupleTableSlot *
MongoExecForeignInsert(EState *estate,
ResultRelInfo *resultRelInfo,
TupleTableSlot *slot,
TupleTableSlot *planSlot)
{
MongoFdwOptions *options = NULL;
MONGO_CONN *mongoConnection = NULL;
Oid foreignTableId = InvalidOid;
BSON *b = NULL;
Oid typoid;
Datum value;
bool isnull = false;
Oid userid;
ForeignServer *server;
UserMapping *user;
ForeignTable *table;
MongoFdwModifyState *fmstate = (MongoFdwModifyState *) resultRelInfo->ri_FdwState;
foreignTableId = RelationGetRelid(resultRelInfo->ri_RelationDesc);
userid = GetUserId();
/* Get info about foreign table. */
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.
*/
options = fmstate->options;
mongoConnection = mongo_get_connection(server, user, options);
b = BsonCreate();
typoid = get_atttype(foreignTableId, 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 (strcmp(slot->tts_tupleDescriptor->attrs[0]->attname.data, "_id") != 0)
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 (strcmp(slot->tts_tupleDescriptor->attrs[0]->attname.data, "__doc") == 0)
continue;
if (attnum == 1)
{
/*
* Ignore the value of first column which is row identifier in MongoDb (_id)
* and let MongoDB to insert the unique value for that column.
*/
}
else
{
AppenMongoValue(b, slot->tts_tupleDescriptor->attrs[attnum - 1]->attname.data, value,
isnull, slot->tts_tupleDescriptor->attrs[attnum -1]->atttypid);
}
}
}
BsonFinish(b);
/* Now we are ready to insert tuple / document into MongoDB */
MongoInsert(mongoConnection, options->svr_database, options->collectionName, b);
BsonDestroy(b);
return slot;
}
/*
* Add column(s) needed for update/delete on a foreign table, we are using
* first column as row identification column, so we are adding that into target
* list.
*/
static void
MongoAddForeignUpdateTargets(Query *parsetree,
RangeTblEntry *target_rte,
Relation target_relation)
{
Var *var = NULL;
const char *attrname = NULL;
TargetEntry *tle = NULL;
/*
* What we need is the rowid which is the first column
*/
Form_pg_attribute attr =
RelationGetDescr(target_relation)->attrs[0];
/* Make a Var representing the desired value */
var = makeVar(parsetree->resultRelation,
1,
attr->atttypid,
attr->atttypmod,
InvalidOid,
0);
/* Wrap it in a TLE with the right name ... */
attrname = NameStr(attr->attname);
tle = makeTargetEntry((Expr *) var,
list_length(parsetree->targetList) + 1,
pstrdup(attrname),
true);
/* ... and add it to the query's targetlist */
parsetree->targetList = lappend(parsetree->targetList, tle);
}
static TupleTableSlot *
MongoExecForeignUpdate(EState *estate,
ResultRelInfo *resultRelInfo,
TupleTableSlot *slot,
TupleTableSlot *planSlot)
{
MongoFdwOptions *options = NULL;
MONGO_CONN *mongoConnection = NULL;
Datum datum = 0;
bool isNull = false;
Oid foreignTableId = InvalidOid;
char *columnName = NULL;
Oid typoid = InvalidOid;
BSON *b = NULL;
BSON *op = NULL;
BSON set;
Oid userid = GetUserId();
ForeignServer *server;
UserMapping *user;
ForeignTable *table;
MongoFdwModifyState *fmstate = (MongoFdwModifyState *) resultRelInfo->ri_FdwState;
foreignTableId = RelationGetRelid(resultRelInfo->ri_RelationDesc);
/* resolve foreign table options; and connect to mongo server */
options = fmstate->options;
/* Get info about foreign table. */
table = GetForeignTable(foreignTableId);
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);
/* Get the id that was passed up as a resjunk column */
datum = ExecGetJunkAttribute(planSlot, 1, &isNull);
columnName = get_relid_attribute_name(foreignTableId, 1);
typoid = get_atttype(foreignTableId, 1);
b = BsonCreate();
BsonAppendStartObject(b, "$set", &set);
/* get following parameters from slot */
if (slot != NULL && fmstate->target_attrs != NIL)
{
ListCell *lc;
foreach(lc, fmstate->target_attrs)
{
int attnum = lfirst_int(lc);
Datum value;
bool isnull;
if (strcmp("_id", slot->tts_tupleDescriptor->attrs[attnum - 1]->attname.data) == 0)
continue;
if (strcmp("__doc", slot->tts_tupleDescriptor->attrs[attnum - 1]->attname.data) == 0)
elog(ERROR, "system column '__doc' update is not supported");
value = slot_getattr(slot, attnum, &isnull);
#ifdef META_DRIVER
AppenMongoValue(&set, slot->tts_tupleDescriptor->attrs[attnum - 1]->attname.data, value,
isnull ? true : false, slot->tts_tupleDescriptor->attrs[attnum - 1]->atttypid);
#else
AppenMongoValue(b, slot->tts_tupleDescriptor->attrs[attnum - 1]->attname.data, value,
isnull ? true : false, slot->tts_tupleDescriptor->attrs[attnum - 1]->atttypid);
#endif
}
}
BsonAppendFinishObject(b, &set);
BsonFinish(b);
op = BsonCreate();
if (!AppenMongoValue(op, columnName, datum, false, typoid))
{
BsonDestroy(b);
return NULL;
}
BsonFinish(op);
/* We are ready to update the row into MongoDB */
MongoUpdate(mongoConnection, options->svr_database, options->collectionName, op, b);
BsonDestroy(op);
BsonDestroy(b);
/* Return NULL if nothing was updated on the remote end */
return slot;
}
/*
* MongoExecForeignDelete
* Delete one row from a foreign table
*/
static TupleTableSlot *
MongoExecForeignDelete(EState *estate,
ResultRelInfo *resultRelInfo,
TupleTableSlot *slot,
TupleTableSlot *planSlot)
{
MongoFdwOptions *options = NULL;
MONGO_CONN *mongoConnection = NULL;
Datum datum = 0;
bool isNull = false;
Oid foreignTableId = InvalidOid;
char *columnName = NULL;
Oid typoid = InvalidOid;
BSON *b = NULL;