depthFirstSearch.c File Reference

Connecting code with postgres. More...

#include <stdbool.h>
#include "c_common/postgres_connection.h"
#include "utils/array.h"
#include "c_common/debug_macro.h"
#include "c_common/e_report.h"
#include "c_common/time_msg.h"
#include "c_common/edges_input.h"
#include "c_common/arrays_input.h"
#include "drivers/traversal/depthFirstSearch_driver.h"

Include dependency graph for depthFirstSearch.c:

Go to the source code of this file.

Functions
PGDLLEXPORT Datum	_pgr_depthfirstsearch (PG_FUNCTION_ARGS)
	Helps in converting postgres variables to C variables, and returns the result. More...
	PG_FUNCTION_INFO_V1 (_pgr_depthfirstsearch)
static void	process (char *edges_sql, ArrayType *roots, bool directed, int64_t max_depth, pgr_mst_rt **result_tuples, size_t *result_count)
	Static function, loads the data from postgres to C types for further processing. More...

Detailed Description

Connecting code with postgres.

Definition in file depthFirstSearch.c.

Function Documentation

_pgr_depthfirstsearch()

PGDLLEXPORT Datum _pgr_depthfirstsearch

(

PG_FUNCTION_ARGS

)

Helps in converting postgres variables to C variables, and returns the result.

Definition at line 133 of file depthFirstSearch.c.

                                                          {
    FuncCallContext     *funcctx;
    TupleDesc           tuple_desc;
 
    /**********************************************************************/
    pgr_mst_rt *result_tuples = NULL;
    size_t result_count = 0;
    /**********************************************************************/
 
    if (SRF_IS_FIRSTCALL()) {
        MemoryContext   oldcontext;
        funcctx = SRF_FIRSTCALL_INIT();
        oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
 
        /***********************************************************************
         *
         *   pgr_depthFirstSearch(
         *       edges_sql TEXT,
         *       root_vids ANYARRAY,
         *       directed BOOLEAN DEFAULT true
         *       max_depth BIGINT DEFAULT 9223372036854775807,
         *   );
         *
         **********************************************************************/
 
        process(
                text_to_cstring(PG_GETARG_TEXT_P(0)),
                PG_GETARG_ARRAYTYPE_P(1),
                PG_GETARG_BOOL(2),
                PG_GETARG_INT64(3),
                &result_tuples,
                &result_count);
 
        /**********************************************************************/
 
 
#if PGSQL_VERSION > 95
        funcctx->max_calls = result_count;
#else
        funcctx->max_calls = (uint32_t)result_count;
#endif
        funcctx->user_fctx = result_tuples;
        if (get_call_result_type(fcinfo, NULL, &tuple_desc)
                != TYPEFUNC_COMPOSITE) {
            ereport(ERROR,
                    (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                     errmsg("function returning record called in context "
                         "that cannot accept type record")));
        }
 
        funcctx->tuple_desc = tuple_desc;
        MemoryContextSwitchTo(oldcontext);
    }
 
    funcctx = SRF_PERCALL_SETUP();
    tuple_desc = funcctx->tuple_desc;
    result_tuples = (pgr_mst_rt*) funcctx->user_fctx;
 
    if (funcctx->call_cntr < funcctx->max_calls) {
        HeapTuple    tuple;
        Datum        result;
        Datum        *values;
        bool*        nulls;
 
        /***********************************************************************
         *
         *   OUT seq BIGINT,
         *   OUT depth BIGINT,
         *   OUT start_vid BIGINT,
         *   OUT node BIGINT,
         *   OUT edge BIGINT,
         *   OUT cost FLOAT,
         *   OUT agg_cost FLOAT
         *
         **********************************************************************/
 
        size_t num  = 7;
        values = palloc(num * sizeof(Datum));
        nulls = palloc(num * sizeof(bool));
 
 
        size_t i;
        for (i = 0; i < num; ++i) {
            nulls[i] = false;
        }
 
        values[0] = Int64GetDatum(funcctx->call_cntr + 1);
        values[1] = Int64GetDatum(result_tuples[funcctx->call_cntr].depth);
        values[2] = Int64GetDatum(result_tuples[funcctx->call_cntr].from_v);
        values[3] = Int64GetDatum(result_tuples[funcctx->call_cntr].node);
        values[4] = Int64GetDatum(result_tuples[funcctx->call_cntr].edge);
        values[5] = Float8GetDatum(result_tuples[funcctx->call_cntr].cost);
        values[6] = Float8GetDatum(result_tuples[funcctx->call_cntr].agg_cost);
 
        /**********************************************************************/
 
        tuple = heap_form_tuple(tuple_desc, values, nulls);
        result = HeapTupleGetDatum(tuple);
        SRF_RETURN_NEXT(funcctx, result);
    } else {
        SRF_RETURN_DONE(funcctx);
    }
}

References pgr_mst_rt::agg_cost, pgr_mst_rt::cost, pgr_mst_rt::depth, pgr_mst_rt::edge, pgr_mst_rt::from_v, if(), pgr_mst_rt::node, and process().

PG_FUNCTION_INFO_V1()

PG_FUNCTION_INFO_V1

(

_pgr_depthfirstsearch

)

process()

static void process ( char *  edges_sql, ArrayType *  roots, bool  directed, int64_t  max_depth, pgr_mst_rt **  result_tuples, size_t *  result_count  )

static

Static function, loads the data from postgres to C types for further processing.

It first connects the C function to the SPI manager. Then converts the postgres array to C array and loads the edges belonging to the graph in C types. Then it calls the function do_pgr_depthFirstSearch defined in the depthFirstSearch_driver.h file for further processing. Finally, it frees the memory and disconnects the C function to the SPI manager.

Parameters

edges_sql	the edges of the SQL query
roots	the root vertices
directed	whether the graph is directed or undirected
max_depth	the maximum depth of traversal
result_tuples	the rows in the result
result_count	the count of rows in the result

Returns

void

Definition at line 69 of file depthFirstSearch.c.

                              {
    pgr_SPI_connect();
 
    size_t size_rootsArr = 0;
 
    int64_t* rootsArr = (int64_t*) pgr_get_bigIntArray(&size_rootsArr, roots);
 
    (*result_tuples) = NULL;
    (*result_count) = 0;
 
    pgr_edge_t *edges = NULL;
    size_t total_edges = 0;
 
    pgr_get_edges(edges_sql, &edges, &total_edges);
 
    clock_t start_t = clock();
    char *log_msg = NULL;
    char *notice_msg = NULL;
    char *err_msg = NULL;
    do_pgr_depthFirstSearch(
            edges, total_edges,
            rootsArr, size_rootsArr,
 
            directed,
            max_depth,
 
            result_tuples,
            result_count,
            &log_msg,
            &notice_msg,
            &err_msg);
 
    time_msg("processing pgr_depthFirstSearch", start_t, clock());
 
    if (err_msg && (*result_tuples)) {
        pfree(*result_tuples);
        (*result_tuples) = NULL;
        (*result_count) = 0;
    }
 
    pgr_global_report(log_msg, notice_msg, err_msg);
 
    if (log_msg) pfree(log_msg);
    if (notice_msg) pfree(notice_msg);
    if (err_msg) pfree(err_msg);
    if (edges) pfree(edges);
    if (rootsArr) pfree(rootsArr);
 
    pgr_SPI_finish();
}

References do_pgr_depthFirstSearch(), pgr_get_bigIntArray(), pgr_get_edges(), pgr_global_report(), pgr_SPI_connect(), pgr_SPI_finish(), and time_msg().

Referenced by _pgr_depthfirstsearch().