tablefunc.c File Reference

#include "postgres.h"
#include <math.h>
#include "access/htup_details.h"
#include "catalog/pg_type.h"
#include "common/pg_prng.h"
#include "executor/spi.h"
#include "funcapi.h"
#include "lib/stringinfo.h"
#include "miscadmin.h"
#include "tablefunc.h"
#include "utils/builtins.h"

Include dependency graph for tablefunc.c:

Go to the source code of this file.

Data Structures
struct	normal_rand_fctx
struct	crosstab_cat_desc
struct	crosstab_hashent

Macros
#define	xpfree(var_)
#define	xpstrdup(tgtvar_, srcvar_)
#define	xstreq(tgtvar_, srcvar_)
#define	INT32_STRLEN   12
#define	MAX_CATNAME_LEN   NAMEDATALEN
#define	INIT_CATS   64
#define	crosstab_HashTableLookup(HASHTAB, CATNAME, CATDESC)
#define	crosstab_HashTableInsert(HASHTAB, CATDESC)
#define	CONNECTBY_NCOLS   4
#define	CONNECTBY_NCOLS_NOBRANCH   3

Typedefs
typedef struct crosstab_cat_desc	crosstab_cat_desc
typedef struct crosstab_hashent	crosstab_HashEnt

Functions
static HTAB *	load_categories_hash (char *cats_sql, MemoryContext per_query_ctx)
static Tuplestorestate *	get_crosstab_tuplestore (char *sql, HTAB *crosstab_hash, TupleDesc tupdesc, bool randomAccess)
static void	validateConnectbyTupleDesc (TupleDesc td, bool show_branch, bool show_serial)
static bool	compatCrosstabTupleDescs (TupleDesc ret_tupdesc, TupleDesc sql_tupdesc)
static void	compatConnectbyTupleDescs (TupleDesc ret_tupdesc, TupleDesc sql_tupdesc)
static void	get_normal_pair (float8 *x1, float8 *x2)
static Tuplestorestate *	connectby (char *relname, char *key_fld, char *parent_key_fld, char *orderby_fld, char *branch_delim, char *start_with, int max_depth, bool show_branch, bool show_serial, MemoryContext per_query_ctx, bool randomAccess, AttInMetadata *attinmeta)
static void	build_tuplestore_recursively (char *key_fld, char *parent_key_fld, char *relname, char *orderby_fld, char *branch_delim, char *start_with, char *branch, int level, int *serial, int max_depth, bool show_branch, bool show_serial, MemoryContext per_query_ctx, AttInMetadata *attinmeta, Tuplestorestate *tupstore)
	PG_FUNCTION_INFO_V1 (normal_rand)
Datum	normal_rand (PG_FUNCTION_ARGS)
	PG_FUNCTION_INFO_V1 (crosstab)
Datum	crosstab (PG_FUNCTION_ARGS)
	PG_FUNCTION_INFO_V1 (crosstab_hash)
Datum	crosstab_hash (PG_FUNCTION_ARGS)
	PG_FUNCTION_INFO_V1 (connectby_text)
Datum	connectby_text (PG_FUNCTION_ARGS)
	PG_FUNCTION_INFO_V1 (connectby_text_serial)
Datum	connectby_text_serial (PG_FUNCTION_ARGS)

Variables
	PG_MODULE_MAGIC

Macro Definition Documentation

CONNECTBY_NCOLS

#define CONNECTBY_NCOLS   4

Definition at line 985 of file tablefunc.c.

CONNECTBY_NCOLS_NOBRANCH

#define CONNECTBY_NCOLS_NOBRANCH   3

Definition at line 986 of file tablefunc.c.

crosstab_HashTableInsert

#define crosstab_HashTableInsert	(		HASHTAB,
			CATDESC
	)

Value:

do { \
    crosstab_HashEnt *hentry; bool found; char key[MAX_CATNAME_LEN]; \
	\
	MemSet(key, 0, MAX_CATNAME_LEN); \
    snprintf(key, MAX_CATNAME_LEN - 1, "%s", CATDESC->catname); \
    hentry = (crosstab_HashEnt*) hash_search(HASHTAB, \
                                         key, HASH_ENTER, &found); \
    if (found) \
        ereport(ERROR, \
                (errcode(ERRCODE_DUPLICATE_OBJECT), \
                 errmsg("duplicate category name"))); \
    hentry->catdesc = CATDESC; \
} while(0)

Definition at line 142 of file tablefunc.c.

crosstab_HashTableLookup

#define crosstab_HashTableLookup	(		HASHTAB,
			CATNAME,
			CATDESC
	)

Value:

do { \
    crosstab_HashEnt *hentry; char key[MAX_CATNAME_LEN]; \
	\
	MemSet(key, 0, MAX_CATNAME_LEN); \
    snprintf(key, MAX_CATNAME_LEN - 1, "%s", CATNAME); \
    hentry = (crosstab_HashEnt*) hash_search(HASHTAB, \
                                         key, HASH_FIND, NULL); \
    if (hentry) \
        CATDESC = hentry->catdesc; \
    else \
        CATDESC = NULL; \
} while(0)

Definition at line 128 of file tablefunc.c.

INIT_CATS

#define INIT_CATS   64

Definition at line 126 of file tablefunc.c.

INT32_STRLEN

#define INT32_STRLEN   12

Definition at line 116 of file tablefunc.c.

MAX_CATNAME_LEN

#define MAX_CATNAME_LEN   NAMEDATALEN

Definition at line 125 of file tablefunc.c.

xpfree

#define xpfree

(

var_

)

Value:

    do { \
        if (var_ != NULL) \
        { \
            pfree(var_); \
            var_ = NULL; \
        } \
    } while (0)

Definition at line 94 of file tablefunc.c.

xpstrdup

#define xpstrdup	(		tgtvar_,
			srcvar_
	)

Value:

    do { \
        if (srcvar_) \
            tgtvar_ = pstrdup(srcvar_); \
        else \
            tgtvar_ = NULL; \
    } while (0)

Definition at line 103 of file tablefunc.c.

xstreq

#define xstreq	(		tgtvar_,
			srcvar_
	)

Value:

    (((tgtvar_ == NULL) && (srcvar_ == NULL)) || \
     ((tgtvar_ != NULL) && (srcvar_ != NULL) && (strcmp(tgtvar_, srcvar_) == 0)))

Definition at line 111 of file tablefunc.c.

Typedef Documentation

crosstab_cat_desc

typedef struct crosstab_cat_desc crosstab_cat_desc

crosstab_HashEnt

typedef struct crosstab_hashent crosstab_HashEnt

Function Documentation

build_tuplestore_recursively()

static void build_tuplestore_recursively ( char *  key_fld, char *  parent_key_fld, char *  relname, char *  orderby_fld, char *  branch_delim, char *  start_with, char *  branch, int  level, int *  serial, int  max_depth, bool  show_branch, bool  show_serial, MemoryContext  per_query_ctx, AttInMetadata *  attinmeta, Tuplestorestate *  tupstore  )

static

Definition at line 1204 of file tablefunc.c.

{
    TupleDesc   tupdesc = attinmeta->tupdesc;
    int         ret;
    uint64      proc;
    int         serial_column;
    StringInfoData sql;
    char      **values;
    char       *current_key;
    char       *current_key_parent;
    char        current_level[INT32_STRLEN];
    char        serial_str[INT32_STRLEN];
    char       *current_branch;
    HeapTuple   tuple;
 
    if (max_depth > 0 && level > max_depth)
        return;
 
    initStringInfo(&sql);
 
    /* Build initial sql statement */
    if (!show_serial)
    {
        appendStringInfo(&sql, "SELECT %s, %s FROM %s WHERE %s = %s AND %s IS NOT NULL AND %s <> %s",
                         key_fld,
                         parent_key_fld,
                         relname,
                         parent_key_fld,
                         quote_literal_cstr(start_with),
                         key_fld, key_fld, parent_key_fld);
        serial_column = 0;
    }
    else
    {
        appendStringInfo(&sql, "SELECT %s, %s FROM %s WHERE %s = %s AND %s IS NOT NULL AND %s <> %s ORDER BY %s",
                         key_fld,
                         parent_key_fld,
                         relname,
                         parent_key_fld,
                         quote_literal_cstr(start_with),
                         key_fld, key_fld, parent_key_fld,
                         orderby_fld);
        serial_column = 1;
    }
 
    if (show_branch)
        values = (char **) palloc((CONNECTBY_NCOLS + serial_column) * sizeof(char *));
    else
        values = (char **) palloc((CONNECTBY_NCOLS_NOBRANCH + serial_column) * sizeof(char *));
 
    /* First time through, do a little setup */
    if (level == 0)
    {
        /* root value is the one we initially start with */
        values[0] = start_with;
 
        /* root value has no parent */
        values[1] = NULL;
 
        /* root level is 0 */
        sprintf(current_level, "%d", level);
        values[2] = current_level;
 
        /* root branch is just starting root value */
        if (show_branch)
            values[3] = start_with;
 
        /* root starts the serial with 1 */
        if (show_serial)
        {
            sprintf(serial_str, "%d", (*serial)++);
            if (show_branch)
                values[4] = serial_str;
            else
                values[3] = serial_str;
        }
 
        /* construct the tuple */
        tuple = BuildTupleFromCStrings(attinmeta, values);
 
        /* now store it */
        tuplestore_puttuple(tupstore, tuple);
 
        /* increment level */
        level++;
    }
 
    /* Retrieve the desired rows */
    ret = SPI_execute(sql.data, true, 0);
    proc = SPI_processed;
 
    /* Check for qualifying tuples */
    if ((ret == SPI_OK_SELECT) && (proc > 0))
    {
        HeapTuple   spi_tuple;
        SPITupleTable *tuptable = SPI_tuptable;
        TupleDesc   spi_tupdesc = tuptable->tupdesc;
        uint64      i;
        StringInfoData branchstr;
        StringInfoData chk_branchstr;
        StringInfoData chk_current_key;
 
        /*
         * Check that return tupdesc is compatible with the one we got from
         * the query.
         */
        compatConnectbyTupleDescs(tupdesc, spi_tupdesc);
 
        initStringInfo(&branchstr);
        initStringInfo(&chk_branchstr);
        initStringInfo(&chk_current_key);
 
        for (i = 0; i < proc; i++)
        {
            /* initialize branch for this pass */
            appendStringInfoString(&branchstr, branch);
            appendStringInfo(&chk_branchstr, "%s%s%s", branch_delim, branch, branch_delim);
 
            /* get the next sql result tuple */
            spi_tuple = tuptable->vals[i];
 
            /* get the current key (might be NULL) */
            current_key = SPI_getvalue(spi_tuple, spi_tupdesc, 1);
 
            /* get the parent key (might be NULL) */
            current_key_parent = SPI_getvalue(spi_tuple, spi_tupdesc, 2);
 
            /* get the current level */
            sprintf(current_level, "%d", level);
 
            /* check to see if this key is also an ancestor */
            if (current_key)
            {
                appendStringInfo(&chk_current_key, "%s%s%s",
                                 branch_delim, current_key, branch_delim);
                if (strstr(chk_branchstr.data, chk_current_key.data))
                    ereport(ERROR,
                            (errcode(ERRCODE_INVALID_RECURSION),
                             errmsg("infinite recursion detected")));
            }
 
            /* OK, extend the branch */
            if (current_key)
                appendStringInfo(&branchstr, "%s%s", branch_delim, current_key);
            current_branch = branchstr.data;
 
            /* build a tuple */
            values[0] = current_key;
            values[1] = current_key_parent;
            values[2] = current_level;
            if (show_branch)
                values[3] = current_branch;
            if (show_serial)
            {
                sprintf(serial_str, "%d", (*serial)++);
                if (show_branch)
                    values[4] = serial_str;
                else
                    values[3] = serial_str;
            }
 
            tuple = BuildTupleFromCStrings(attinmeta, values);
 
            /* store the tuple for later use */
            tuplestore_puttuple(tupstore, tuple);
 
            heap_freetuple(tuple);
 
            /* recurse using current_key as the new start_with */
            if (current_key)
                build_tuplestore_recursively(key_fld,
                                             parent_key_fld,
                                             relname,
                                             orderby_fld,
                                             branch_delim,
                                             current_key,
                                             current_branch,
                                             level + 1,
                                             serial,
                                             max_depth,
                                             show_branch,
                                             show_serial,
                                             per_query_ctx,
                                             attinmeta,
                                             tupstore);
 
            xpfree(current_key);
            xpfree(current_key_parent);
 
            /* reset branch for next pass */
            resetStringInfo(&branchstr);
            resetStringInfo(&chk_branchstr);
            resetStringInfo(&chk_current_key);
        }
 
        xpfree(branchstr.data);
        xpfree(chk_branchstr.data);
        xpfree(chk_current_key.data);
    }
}

References appendStringInfo(), appendStringInfoString(), BuildTupleFromCStrings(), compatConnectbyTupleDescs(), CONNECTBY_NCOLS, CONNECTBY_NCOLS_NOBRANCH, StringInfoData::data, ereport, errcode(), errmsg(), ERROR, heap_freetuple(), i, initStringInfo(), INT32_STRLEN, palloc(), quote_literal_cstr(), relname, resetStringInfo(), SPI_execute(), SPI_getvalue(), SPI_OK_SELECT, SPI_processed, SPI_tuptable, sprintf, SPITupleTable::tupdesc, AttInMetadata::tupdesc, tuplestore_puttuple(), SPITupleTable::vals, values, and xpfree.

Referenced by connectby().

compatConnectbyTupleDescs()

static void compatConnectbyTupleDescs ( TupleDesc  ret_tupdesc, TupleDesc  sql_tupdesc  )

static

Definition at line 1498 of file tablefunc.c.

{
    Oid         ret_atttypid;
    Oid         sql_atttypid;
    int32       ret_atttypmod;
    int32       sql_atttypmod;
 
    /*
     * Result must have at least 2 columns.
     */
    if (sql_tupdesc->natts < 2)
        ereport(ERROR,
                (errcode(ERRCODE_DATATYPE_MISMATCH),
                 errmsg("invalid return type"),
                 errdetail("Query must return at least two columns.")));
 
    /*
     * These columns must match the result type indicated by the calling
     * query.
     */
    ret_atttypid = TupleDescAttr(ret_tupdesc, 0)->atttypid;
    sql_atttypid = TupleDescAttr(sql_tupdesc, 0)->atttypid;
    ret_atttypmod = TupleDescAttr(ret_tupdesc, 0)->atttypmod;
    sql_atttypmod = TupleDescAttr(sql_tupdesc, 0)->atttypmod;
    if (ret_atttypid != sql_atttypid ||
        (ret_atttypmod >= 0 && ret_atttypmod != sql_atttypmod))
        ereport(ERROR,
                (errcode(ERRCODE_DATATYPE_MISMATCH),
                 errmsg("invalid return type"),
                 errdetail("SQL key field type %s does " \
                           "not match return key field type %s.",
                           format_type_with_typemod(ret_atttypid, ret_atttypmod),
                           format_type_with_typemod(sql_atttypid, sql_atttypmod))));
 
    ret_atttypid = TupleDescAttr(ret_tupdesc, 1)->atttypid;
    sql_atttypid = TupleDescAttr(sql_tupdesc, 1)->atttypid;
    ret_atttypmod = TupleDescAttr(ret_tupdesc, 1)->atttypmod;
    sql_atttypmod = TupleDescAttr(sql_tupdesc, 1)->atttypmod;
    if (ret_atttypid != sql_atttypid ||
        (ret_atttypmod >= 0 && ret_atttypmod != sql_atttypmod))
        ereport(ERROR,
                (errcode(ERRCODE_DATATYPE_MISMATCH),
                 errmsg("invalid return type"),
                 errdetail("SQL parent key field type %s does " \
                           "not match return parent key field type %s.",
                           format_type_with_typemod(ret_atttypid, ret_atttypmod),
                           format_type_with_typemod(sql_atttypid, sql_atttypmod))));
 
    /* OK, the two tupdescs are compatible for our purposes */
}

References ereport, errcode(), errdetail(), errmsg(), ERROR, format_type_with_typemod(), TupleDescData::natts, and TupleDescAttr.

Referenced by build_tuplestore_recursively().

compatCrosstabTupleDescs()

static bool compatCrosstabTupleDescs ( TupleDesc  ret_tupdesc, TupleDesc  sql_tupdesc  )

static

Definition at line 1553 of file tablefunc.c.

{
    int         i;
    Form_pg_attribute ret_attr;
    Oid         ret_atttypid;
    Form_pg_attribute sql_attr;
    Oid         sql_atttypid;
 
    if (ret_tupdesc->natts < 2 ||
        sql_tupdesc->natts < 3)
        return false;
 
    /* check the rowid types match */
    ret_atttypid = TupleDescAttr(ret_tupdesc, 0)->atttypid;
    sql_atttypid = TupleDescAttr(sql_tupdesc, 0)->atttypid;
    if (ret_atttypid != sql_atttypid)
        ereport(ERROR,
                (errcode(ERRCODE_DATATYPE_MISMATCH),
                 errmsg("invalid return type"),
                 errdetail("SQL rowid datatype does not match " \
                           "return rowid datatype.")));
 
    /*
     * - attribute [1] of the sql tuple is the category; no need to check it -
     * attribute [2] of the sql tuple should match attributes [1] to [natts]
     * of the return tuple
     */
    sql_attr = TupleDescAttr(sql_tupdesc, 2);
    for (i = 1; i < ret_tupdesc->natts; i++)
    {
        ret_attr = TupleDescAttr(ret_tupdesc, i);
 
        if (ret_attr->atttypid != sql_attr->atttypid)
            return false;
    }
 
    /* OK, the two tupdescs are compatible for our purposes */
    return true;
}

References ereport, errcode(), errdetail(), errmsg(), ERROR, i, TupleDescData::natts, and TupleDescAttr.

Referenced by crosstab().

connectby()

static Tuplestorestate * connectby ( char *  relname, char *  key_fld, char *  parent_key_fld, char *  orderby_fld, char *  branch_delim, char *  start_with, int  max_depth, bool  show_branch, bool  show_serial, MemoryContext  per_query_ctx, bool  randomAccess, AttInMetadata *  attinmeta  )

static

Definition at line 1149 of file tablefunc.c.

{
    Tuplestorestate *tupstore = NULL;
    int         ret;
    MemoryContext oldcontext;
 
    int         serial = 1;
 
    /* Connect to SPI manager */
    if ((ret = SPI_connect()) < 0)
        /* internal error */
        elog(ERROR, "connectby: SPI_connect returned %d", ret);
 
    /* switch to longer term context to create the tuple store */
    oldcontext = MemoryContextSwitchTo(per_query_ctx);
 
    /* initialize our tuplestore */
    tupstore = tuplestore_begin_heap(randomAccess, false, work_mem);
 
    MemoryContextSwitchTo(oldcontext);
 
    /* now go get the whole tree */
    build_tuplestore_recursively(key_fld,
                                 parent_key_fld,
                                 relname,
                                 orderby_fld,
                                 branch_delim,
                                 start_with,
                                 start_with,    /* current_branch */
                                 0, /* initial level is 0 */
                                 &serial,   /* initial serial is 1 */
                                 max_depth,
                                 show_branch,
                                 show_serial,
                                 per_query_ctx,
                                 attinmeta,
                                 tupstore);
 
    SPI_finish();
 
    return tupstore;
}

References build_tuplestore_recursively(), elog(), ERROR, MemoryContextSwitchTo(), relname, SPI_connect(), SPI_finish(), tuplestore_begin_heap(), and work_mem.

Referenced by connectby_text(), and connectby_text_serial().

connectby_text()

Datum connectby_text

(

PG_FUNCTION_ARGS

)

Definition at line 989 of file tablefunc.c.

{
    char       *relname = text_to_cstring(PG_GETARG_TEXT_PP(0));
    char       *key_fld = text_to_cstring(PG_GETARG_TEXT_PP(1));
    char       *parent_key_fld = text_to_cstring(PG_GETARG_TEXT_PP(2));
    char       *start_with = text_to_cstring(PG_GETARG_TEXT_PP(3));
    int         max_depth = PG_GETARG_INT32(4);
    char       *branch_delim = NULL;
    bool        show_branch = false;
    bool        show_serial = false;
    ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
    TupleDesc   tupdesc;
    AttInMetadata *attinmeta;
    MemoryContext per_query_ctx;
    MemoryContext oldcontext;
 
    /* check to see if caller supports us returning a tuplestore */
    if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
        ereport(ERROR,
                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                 errmsg("set-valued function called in context that cannot accept a set")));
    if (!(rsinfo->allowedModes & SFRM_Materialize) ||
        rsinfo->expectedDesc == NULL)
        ereport(ERROR,
                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                 errmsg("materialize mode required, but it is not allowed in this context")));
 
    if (fcinfo->nargs == 6)
    {
        branch_delim = text_to_cstring(PG_GETARG_TEXT_PP(5));
        show_branch = true;
    }
    else
        /* default is no show, tilde for the delimiter */
        branch_delim = pstrdup("~");
 
    per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
    oldcontext = MemoryContextSwitchTo(per_query_ctx);
 
    /* get the requested return tuple description */
    tupdesc = CreateTupleDescCopy(rsinfo->expectedDesc);
 
    /* does it meet our needs */
    validateConnectbyTupleDesc(tupdesc, show_branch, show_serial);
 
    /* OK, use it then */
    attinmeta = TupleDescGetAttInMetadata(tupdesc);
 
    /* OK, go to work */
    rsinfo->returnMode = SFRM_Materialize;
    rsinfo->setResult = connectby(relname,
                                  key_fld,
                                  parent_key_fld,
                                  NULL,
                                  branch_delim,
                                  start_with,
                                  max_depth,
                                  show_branch,
                                  show_serial,
                                  per_query_ctx,
                                  rsinfo->allowedModes & SFRM_Materialize_Random,
                                  attinmeta);
    rsinfo->setDesc = tupdesc;
 
    MemoryContextSwitchTo(oldcontext);
 
    /*
     * SFRM_Materialize mode expects us to return a NULL Datum. The actual
     * tuples are in our tuplestore and passed back through rsinfo->setResult.
     * rsinfo->setDesc is set to the tuple description that we actually used
     * to build our tuples with, so the caller can verify we did what it was
     * expecting.
     */
    return (Datum) 0;
}

References ReturnSetInfo::allowedModes, connectby(), CreateTupleDescCopy(), ReturnSetInfo::econtext, ExprContext::ecxt_per_query_memory, ereport, errcode(), errmsg(), ERROR, ReturnSetInfo::expectedDesc, if(), IsA, MemoryContextSwitchTo(), PG_GETARG_INT32, PG_GETARG_TEXT_PP, pstrdup(), relname, ReturnSetInfo::returnMode, ReturnSetInfo::setDesc, ReturnSetInfo::setResult, SFRM_Materialize, SFRM_Materialize_Random, text_to_cstring(), TupleDescGetAttInMetadata(), and validateConnectbyTupleDesc().

connectby_text_serial()

Datum connectby_text_serial

(

PG_FUNCTION_ARGS

)

Definition at line 1067 of file tablefunc.c.

{
    char       *relname = text_to_cstring(PG_GETARG_TEXT_PP(0));
    char       *key_fld = text_to_cstring(PG_GETARG_TEXT_PP(1));
    char       *parent_key_fld = text_to_cstring(PG_GETARG_TEXT_PP(2));
    char       *orderby_fld = text_to_cstring(PG_GETARG_TEXT_PP(3));
    char       *start_with = text_to_cstring(PG_GETARG_TEXT_PP(4));
    int         max_depth = PG_GETARG_INT32(5);
    char       *branch_delim = NULL;
    bool        show_branch = false;
    bool        show_serial = true;
    ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
    TupleDesc   tupdesc;
    AttInMetadata *attinmeta;
    MemoryContext per_query_ctx;
    MemoryContext oldcontext;
 
    /* check to see if caller supports us returning a tuplestore */
    if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
        ereport(ERROR,
                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                 errmsg("set-valued function called in context that cannot accept a set")));
    if (!(rsinfo->allowedModes & SFRM_Materialize) ||
        rsinfo->expectedDesc == NULL)
        ereport(ERROR,
                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                 errmsg("materialize mode required, but it is not allowed in this context")));
 
    if (fcinfo->nargs == 7)
    {
        branch_delim = text_to_cstring(PG_GETARG_TEXT_PP(6));
        show_branch = true;
    }
    else
        /* default is no show, tilde for the delimiter */
        branch_delim = pstrdup("~");
 
    per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
    oldcontext = MemoryContextSwitchTo(per_query_ctx);
 
    /* get the requested return tuple description */
    tupdesc = CreateTupleDescCopy(rsinfo->expectedDesc);
 
    /* does it meet our needs */
    validateConnectbyTupleDesc(tupdesc, show_branch, show_serial);
 
    /* OK, use it then */
    attinmeta = TupleDescGetAttInMetadata(tupdesc);
 
    /* OK, go to work */
    rsinfo->returnMode = SFRM_Materialize;
    rsinfo->setResult = connectby(relname,
                                  key_fld,
                                  parent_key_fld,
                                  orderby_fld,
                                  branch_delim,
                                  start_with,
                                  max_depth,
                                  show_branch,
                                  show_serial,
                                  per_query_ctx,
                                  rsinfo->allowedModes & SFRM_Materialize_Random,
                                  attinmeta);
    rsinfo->setDesc = tupdesc;
 
    MemoryContextSwitchTo(oldcontext);
 
    /*
     * SFRM_Materialize mode expects us to return a NULL Datum. The actual
     * tuples are in our tuplestore and passed back through rsinfo->setResult.
     * rsinfo->setDesc is set to the tuple description that we actually used
     * to build our tuples with, so the caller can verify we did what it was
     * expecting.
     */
    return (Datum) 0;
}

References ReturnSetInfo::allowedModes, connectby(), CreateTupleDescCopy(), ReturnSetInfo::econtext, ExprContext::ecxt_per_query_memory, ereport, errcode(), errmsg(), ERROR, ReturnSetInfo::expectedDesc, if(), IsA, MemoryContextSwitchTo(), PG_GETARG_INT32, PG_GETARG_TEXT_PP, pstrdup(), relname, ReturnSetInfo::returnMode, ReturnSetInfo::setDesc, ReturnSetInfo::setResult, SFRM_Materialize, SFRM_Materialize_Random, text_to_cstring(), TupleDescGetAttInMetadata(), and validateConnectbyTupleDesc().

crosstab()

Datum crosstab

(

PG_FUNCTION_ARGS

)

Definition at line 355 of file tablefunc.c.

{
    char       *sql = text_to_cstring(PG_GETARG_TEXT_PP(0));
    ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
    Tuplestorestate *tupstore;
    TupleDesc   tupdesc;
    uint64      call_cntr;
    uint64      max_calls;
    AttInMetadata *attinmeta;
    SPITupleTable *spi_tuptable;
    TupleDesc   spi_tupdesc;
    bool        firstpass;
    char       *lastrowid;
    int         i;
    int         num_categories;
    MemoryContext per_query_ctx;
    MemoryContext oldcontext;
    int         ret;
    uint64      proc;
 
    /* check to see if caller supports us returning a tuplestore */
    if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
        ereport(ERROR,
                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                 errmsg("set-valued function called in context that cannot accept a set")));
    if (!(rsinfo->allowedModes & SFRM_Materialize))
        ereport(ERROR,
                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                 errmsg("materialize mode required, but it is not allowed in this context")));
 
    per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
 
    /* Connect to SPI manager */
    if ((ret = SPI_connect()) < 0)
        /* internal error */
        elog(ERROR, "crosstab: SPI_connect returned %d", ret);
 
    /* Retrieve the desired rows */
    ret = SPI_execute(sql, true, 0);
    proc = SPI_processed;
 
    /* If no qualifying tuples, fall out early */
    if (ret != SPI_OK_SELECT || proc == 0)
    {
        SPI_finish();
        rsinfo->isDone = ExprEndResult;
        PG_RETURN_NULL();
    }
 
    spi_tuptable = SPI_tuptable;
    spi_tupdesc = spi_tuptable->tupdesc;
 
    /*----------
     * The provided SQL query must always return three columns.
     *
     * 1. rowname
     *  the label or identifier for each row in the final result
     * 2. category
     *  the label or identifier for each column in the final result
     * 3. values
     *  the value for each column in the final result
     *----------
     */
    if (spi_tupdesc->natts != 3)
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                 errmsg("invalid source data SQL statement"),
                 errdetail("The provided SQL must return 3 "
                           "columns: rowid, category, and values.")));
 
    /* get a tuple descriptor for our result type */
    switch (get_call_result_type(fcinfo, NULL, &tupdesc))
    {
        case TYPEFUNC_COMPOSITE:
            /* success */
            break;
        case TYPEFUNC_RECORD:
            /* failed to determine actual type of RECORD */
            ereport(ERROR,
                    (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                     errmsg("function returning record called in context "
                            "that cannot accept type record")));
            break;
        default:
            /* result type isn't composite */
            ereport(ERROR,
                    (errcode(ERRCODE_DATATYPE_MISMATCH),
                     errmsg("return type must be a row type")));
            break;
    }
 
    /*
     * Check that return tupdesc is compatible with the data we got from SPI,
     * at least based on number and type of attributes
     */
    if (!compatCrosstabTupleDescs(tupdesc, spi_tupdesc))
        ereport(ERROR,
                (errcode(ERRCODE_SYNTAX_ERROR),
                 errmsg("return and sql tuple descriptions are " \
                        "incompatible")));
 
    /*
     * switch to long-lived memory context
     */
    oldcontext = MemoryContextSwitchTo(per_query_ctx);
 
    /* make sure we have a persistent copy of the result tupdesc */
    tupdesc = CreateTupleDescCopy(tupdesc);
 
    /* initialize our tuplestore in long-lived context */
    tupstore =
        tuplestore_begin_heap(rsinfo->allowedModes & SFRM_Materialize_Random,
                              false, work_mem);
 
    MemoryContextSwitchTo(oldcontext);
 
    /*
     * Generate attribute metadata needed later to produce tuples from raw C
     * strings
     */
    attinmeta = TupleDescGetAttInMetadata(tupdesc);
 
    /* total number of tuples to be examined */
    max_calls = proc;
 
    /* the return tuple always must have 1 rowid + num_categories columns */
    num_categories = tupdesc->natts - 1;
 
    firstpass = true;
    lastrowid = NULL;
 
    for (call_cntr = 0; call_cntr < max_calls; call_cntr++)
    {
        bool        skip_tuple = false;
        char      **values;
 
        /* allocate and zero space */
        values = (char **) palloc0((1 + num_categories) * sizeof(char *));
 
        /*
         * now loop through the sql results and assign each value in sequence
         * to the next category
         */
        for (i = 0; i < num_categories; i++)
        {
            HeapTuple   spi_tuple;
            char       *rowid;
 
            /* see if we've gone too far already */
            if (call_cntr >= max_calls)
                break;
 
            /* get the next sql result tuple */
            spi_tuple = spi_tuptable->vals[call_cntr];
 
            /* get the rowid from the current sql result tuple */
            rowid = SPI_getvalue(spi_tuple, spi_tupdesc, 1);
 
            /*
             * If this is the first pass through the values for this rowid,
             * set the first column to rowid
             */
            if (i == 0)
            {
                xpstrdup(values[0], rowid);
 
                /*
                 * Check to see if the rowid is the same as that of the last
                 * tuple sent -- if so, skip this tuple entirely
                 */
                if (!firstpass && xstreq(lastrowid, rowid))
                {
                    xpfree(rowid);
                    skip_tuple = true;
                    break;
                }
            }
 
            /*
             * If rowid hasn't changed on us, continue building the output
             * tuple.
             */
            if (xstreq(rowid, values[0]))
            {
                /*
                 * Get the next category item value, which is always attribute
                 * number three.
                 *
                 * Be careful to assign the value to the array index based on
                 * which category we are presently processing.
                 */
                values[1 + i] = SPI_getvalue(spi_tuple, spi_tupdesc, 3);
 
                /*
                 * increment the counter since we consume a row for each
                 * category, but not for last pass because the outer loop will
                 * do that for us
                 */
                if (i < (num_categories - 1))
                    call_cntr++;
                xpfree(rowid);
            }
            else
            {
                /*
                 * We'll fill in NULLs for the missing values, but we need to
                 * decrement the counter since this sql result row doesn't
                 * belong to the current output tuple.
                 */
                call_cntr--;
                xpfree(rowid);
                break;
            }
        }
 
        if (!skip_tuple)
        {
            HeapTuple   tuple;
 
            /* build the tuple and store it */
            tuple = BuildTupleFromCStrings(attinmeta, values);
            tuplestore_puttuple(tupstore, tuple);
            heap_freetuple(tuple);
        }
 
        /* Remember current rowid */
        xpfree(lastrowid);
        xpstrdup(lastrowid, values[0]);
        firstpass = false;
 
        /* Clean up */
        for (i = 0; i < num_categories + 1; i++)
            if (values[i] != NULL)
                pfree(values[i]);
        pfree(values);
    }
 
    /* let the caller know we're sending back a tuplestore */
    rsinfo->returnMode = SFRM_Materialize;
    rsinfo->setResult = tupstore;
    rsinfo->setDesc = tupdesc;
 
    /* release SPI related resources (and return to caller's context) */
    SPI_finish();
 
    return (Datum) 0;
}

References ReturnSetInfo::allowedModes, BuildTupleFromCStrings(), compatCrosstabTupleDescs(), CreateTupleDescCopy(), ReturnSetInfo::econtext, ExprContext::ecxt_per_query_memory, elog(), ereport, errcode(), errdetail(), errmsg(), ERROR, ExprEndResult, get_call_result_type(), heap_freetuple(), i, if(), IsA, ReturnSetInfo::isDone, MemoryContextSwitchTo(), palloc0(), pfree(), PG_GETARG_TEXT_PP, PG_RETURN_NULL, ReturnSetInfo::returnMode, ReturnSetInfo::setDesc, ReturnSetInfo::setResult, SFRM_Materialize, SFRM_Materialize_Random, SPI_connect(), SPI_execute(), SPI_finish(), SPI_getvalue(), SPI_OK_SELECT, SPI_processed, SPI_tuptable, text_to_cstring(), SPITupleTable::tupdesc, TupleDescGetAttInMetadata(), tuplestore_begin_heap(), tuplestore_puttuple(), TYPEFUNC_COMPOSITE, TYPEFUNC_RECORD, values, work_mem, xpfree, xpstrdup, and xstreq.

crosstab_hash()

Datum crosstab_hash

(

PG_FUNCTION_ARGS

)

Definition at line 640 of file tablefunc.c.

{
    char       *sql = text_to_cstring(PG_GETARG_TEXT_PP(0));
    char       *cats_sql = text_to_cstring(PG_GETARG_TEXT_PP(1));
    ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
    TupleDesc   tupdesc;
    MemoryContext per_query_ctx;
    MemoryContext oldcontext;
    HTAB       *crosstab_hash;
 
    /* check to see if caller supports us returning a tuplestore */
    if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
        ereport(ERROR,
                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                 errmsg("set-valued function called in context that cannot accept a set")));
    if (!(rsinfo->allowedModes & SFRM_Materialize) ||
        rsinfo->expectedDesc == NULL)
        ereport(ERROR,
                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                 errmsg("materialize mode required, but it is not allowed in this context")));
 
    per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
    oldcontext = MemoryContextSwitchTo(per_query_ctx);
 
    /* get the requested return tuple description */
    tupdesc = CreateTupleDescCopy(rsinfo->expectedDesc);
 
    /*
     * Check to make sure we have a reasonable tuple descriptor
     *
     * Note we will attempt to coerce the values into whatever the return
     * attribute type is and depend on the "in" function to complain if
     * needed.
     */
    if (tupdesc->natts < 2)
        ereport(ERROR,
                (errcode(ERRCODE_SYNTAX_ERROR),
                 errmsg("query-specified return tuple and " \
                        "crosstab function are not compatible")));
 
    /* load up the categories hash table */
    crosstab_hash = load_categories_hash(cats_sql, per_query_ctx);
 
    /* let the caller know we're sending back a tuplestore */
    rsinfo->returnMode = SFRM_Materialize;
 
    /* now go build it */
    rsinfo->setResult = get_crosstab_tuplestore(sql,
                                                crosstab_hash,
                                                tupdesc,
                                                rsinfo->allowedModes & SFRM_Materialize_Random);
 
    /*
     * SFRM_Materialize mode expects us to return a NULL Datum. The actual
     * tuples are in our tuplestore and passed back through rsinfo->setResult.
     * rsinfo->setDesc is set to the tuple description that we actually used
     * to build our tuples with, so the caller can verify we did what it was
     * expecting.
     */
    rsinfo->setDesc = tupdesc;
    MemoryContextSwitchTo(oldcontext);
 
    return (Datum) 0;
}

References ReturnSetInfo::allowedModes, CreateTupleDescCopy(), ReturnSetInfo::econtext, ExprContext::ecxt_per_query_memory, ereport, errcode(), errmsg(), ERROR, ReturnSetInfo::expectedDesc, get_crosstab_tuplestore(), if(), IsA, load_categories_hash(), MemoryContextSwitchTo(), PG_GETARG_TEXT_PP, ReturnSetInfo::returnMode, ReturnSetInfo::setDesc, ReturnSetInfo::setResult, SFRM_Materialize, SFRM_Materialize_Random, and text_to_cstring().

Referenced by get_crosstab_tuplestore(), and load_categories_hash().

get_crosstab_tuplestore()

static Tuplestorestate * get_crosstab_tuplestore ( char *  sql, HTAB *  crosstab_hash, TupleDesc  tupdesc, bool  randomAccess  )

static

Definition at line 798 of file tablefunc.c.

{
    Tuplestorestate *tupstore;
    int         num_categories = hash_get_num_entries(crosstab_hash);
    AttInMetadata *attinmeta = TupleDescGetAttInMetadata(tupdesc);
    char      **values;
    HeapTuple   tuple;
    int         ret;
    uint64      proc;
 
    /* initialize our tuplestore (while still in query context!) */
    tupstore = tuplestore_begin_heap(randomAccess, false, work_mem);
 
    /* Connect to SPI manager */
    if ((ret = SPI_connect()) < 0)
        /* internal error */
        elog(ERROR, "get_crosstab_tuplestore: SPI_connect returned %d", ret);
 
    /* Now retrieve the crosstab source rows */
    ret = SPI_execute(sql, true, 0);
    proc = SPI_processed;
 
    /* Check for qualifying tuples */
    if ((ret == SPI_OK_SELECT) && (proc > 0))
    {
        SPITupleTable *spi_tuptable = SPI_tuptable;
        TupleDesc   spi_tupdesc = spi_tuptable->tupdesc;
        int         ncols = spi_tupdesc->natts;
        char       *rowid;
        char       *lastrowid = NULL;
        bool        firstpass = true;
        uint64      i;
        int         j;
        int         result_ncols;
 
        if (num_categories == 0)
        {
            /* no qualifying category tuples */
            ereport(ERROR,
                    (errcode(ERRCODE_SYNTAX_ERROR),
                     errmsg("provided \"categories\" SQL must " \
                            "return 1 column of at least one row")));
        }
 
        /*
         * The provided SQL query must always return at least three columns:
         *
         * 1. rowname   the label for each row - column 1 in the final result
         * 2. category  the label for each value-column in the final result 3.
         * value     the values used to populate the value-columns
         *
         * If there are more than three columns, the last two are taken as
         * "category" and "values". The first column is taken as "rowname".
         * Additional columns (2 thru N-2) are assumed the same for the same
         * "rowname", and are copied into the result tuple from the first time
         * we encounter a particular rowname.
         */
        if (ncols < 3)
            ereport(ERROR,
                    (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                     errmsg("invalid source data SQL statement"),
                     errdetail("The provided SQL must return 3 " \
                               " columns; rowid, category, and values.")));
 
        result_ncols = (ncols - 2) + num_categories;
 
        /* Recheck to make sure we tuple descriptor still looks reasonable */
        if (tupdesc->natts != result_ncols)
            ereport(ERROR,
                    (errcode(ERRCODE_SYNTAX_ERROR),
                     errmsg("invalid return type"),
                     errdetail("Query-specified return " \
                               "tuple has %d columns but crosstab " \
                               "returns %d.", tupdesc->natts, result_ncols)));
 
        /* allocate space and make sure it's clear */
        values = (char **) palloc0(result_ncols * sizeof(char *));
 
        for (i = 0; i < proc; i++)
        {
            HeapTuple   spi_tuple;
            crosstab_cat_desc *catdesc;
            char       *catname;
 
            /* get the next sql result tuple */
            spi_tuple = spi_tuptable->vals[i];
 
            /* get the rowid from the current sql result tuple */
            rowid = SPI_getvalue(spi_tuple, spi_tupdesc, 1);
 
            /*
             * if we're on a new output row, grab the column values up to
             * column N-2 now
             */
            if (firstpass || !xstreq(lastrowid, rowid))
            {
                /*
                 * a new row means we need to flush the old one first, unless
                 * we're on the very first row
                 */
                if (!firstpass)
                {
                    /* rowid changed, flush the previous output row */
                    tuple = BuildTupleFromCStrings(attinmeta, values);
 
                    tuplestore_puttuple(tupstore, tuple);
 
                    for (j = 0; j < result_ncols; j++)
                        xpfree(values[j]);
                }
 
                values[0] = rowid;
                for (j = 1; j < ncols - 2; j++)
                    values[j] = SPI_getvalue(spi_tuple, spi_tupdesc, j + 1);
 
                /* we're no longer on the first pass */
                firstpass = false;
            }
 
            /* look up the category and fill in the appropriate column */
            catname = SPI_getvalue(spi_tuple, spi_tupdesc, ncols - 1);
 
            if (catname != NULL)
            {
                crosstab_HashTableLookup(crosstab_hash, catname, catdesc);
 
                if (catdesc)
                    values[catdesc->attidx + ncols - 2] =
                        SPI_getvalue(spi_tuple, spi_tupdesc, ncols);
            }
 
            xpfree(lastrowid);
            xpstrdup(lastrowid, rowid);
        }
 
        /* flush the last output row */
        tuple = BuildTupleFromCStrings(attinmeta, values);
 
        tuplestore_puttuple(tupstore, tuple);
    }
 
    if (SPI_finish() != SPI_OK_FINISH)
        /* internal error */
        elog(ERROR, "get_crosstab_tuplestore: SPI_finish() failed");
 
    return tupstore;
}

References crosstab_cat_desc::attidx, BuildTupleFromCStrings(), crosstab_hash(), crosstab_HashTableLookup, elog(), ereport, errcode(), errdetail(), errmsg(), ERROR, hash_get_num_entries(), i, j, TupleDescData::natts, palloc0(), SPI_connect(), SPI_execute(), SPI_finish(), SPI_getvalue(), SPI_OK_FINISH, SPI_OK_SELECT, SPI_processed, SPI_tuptable, SPITupleTable::tupdesc, TupleDescGetAttInMetadata(), tuplestore_begin_heap(), tuplestore_puttuple(), SPITupleTable::vals, values, work_mem, xpfree, xpstrdup, and xstreq.

Referenced by crosstab_hash().

get_normal_pair()

static void get_normal_pair ( float8 *  x1, float8 *  x2  )

static

Definition at line 284 of file tablefunc.c.

{
    float8      u1,
                u2,
                v1,
                v2,
                s;
 
    do
    {
        u1 = pg_prng_double(&pg_global_prng_state);
        u2 = pg_prng_double(&pg_global_prng_state);
 
        v1 = (2.0 * u1) - 1.0;
        v2 = (2.0 * u2) - 1.0;
 
        s = v1 * v1 + v2 * v2;
    } while (s >= 1.0);
 
    if (s == 0)
    {
        *x1 = 0;
        *x2 = 0;
    }
    else
    {
        s = sqrt((-2.0 * log(s)) / s);
        *x1 = v1 * s;
        *x2 = v2 * s;
    }
}

References pg_global_prng_state, and pg_prng_double().

Referenced by normal_rand().

load_categories_hash()

static HTAB * load_categories_hash ( char *  cats_sql, MemoryContext  per_query_ctx  )

static

Definition at line 709 of file tablefunc.c.

{
    HTAB       *crosstab_hash;
    HASHCTL     ctl;
    int         ret;
    uint64      proc;
    MemoryContext SPIcontext;
 
    /* initialize the category hash table */
    ctl.keysize = MAX_CATNAME_LEN;
    ctl.entrysize = sizeof(crosstab_HashEnt);
    ctl.hcxt = per_query_ctx;
 
    /*
     * use INIT_CATS, defined above as a guess of how many hash table entries
     * to create, initially
     */
    crosstab_hash = hash_create("crosstab hash",
                                INIT_CATS,
                                &ctl,
                                HASH_ELEM | HASH_STRINGS | HASH_CONTEXT);
 
    /* Connect to SPI manager */
    if ((ret = SPI_connect()) < 0)
        /* internal error */
        elog(ERROR, "load_categories_hash: SPI_connect returned %d", ret);
 
    /* Retrieve the category name rows */
    ret = SPI_execute(cats_sql, true, 0);
    proc = SPI_processed;
 
    /* Check for qualifying tuples */
    if ((ret == SPI_OK_SELECT) && (proc > 0))
    {
        SPITupleTable *spi_tuptable = SPI_tuptable;
        TupleDesc   spi_tupdesc = spi_tuptable->tupdesc;
        uint64      i;
 
        /*
         * The provided categories SQL query must always return one column:
         * category - the label or identifier for each column
         */
        if (spi_tupdesc->natts != 1)
            ereport(ERROR,
                    (errcode(ERRCODE_SYNTAX_ERROR),
                     errmsg("provided \"categories\" SQL must " \
                            "return 1 column of at least one row")));
 
        for (i = 0; i < proc; i++)
        {
            crosstab_cat_desc *catdesc;
            char       *catname;
            HeapTuple   spi_tuple;
 
            /* get the next sql result tuple */
            spi_tuple = spi_tuptable->vals[i];
 
            /* get the category from the current sql result tuple */
            catname = SPI_getvalue(spi_tuple, spi_tupdesc, 1);
            if (catname == NULL)
                ereport(ERROR,
                        (errcode(ERRCODE_SYNTAX_ERROR),
                         errmsg("provided \"categories\" SQL must " \
                                "not return NULL values")));
 
            SPIcontext = MemoryContextSwitchTo(per_query_ctx);
 
            catdesc = (crosstab_cat_desc *) palloc(sizeof(crosstab_cat_desc));
            catdesc->catname = catname;
            catdesc->attidx = i;
 
            /* Add the proc description block to the hashtable */
            crosstab_HashTableInsert(crosstab_hash, catdesc);
 
            MemoryContextSwitchTo(SPIcontext);
        }
    }
 
    if (SPI_finish() != SPI_OK_FINISH)
        /* internal error */
        elog(ERROR, "load_categories_hash: SPI_finish() failed");
 
    return crosstab_hash;
}

References crosstab_cat_desc::attidx, crosstab_cat_desc::catname, crosstab_hash(), crosstab_HashTableInsert, elog(), HASHCTL::entrysize, ereport, errcode(), errmsg(), ERROR, HASH_CONTEXT, hash_create(), HASH_ELEM, HASH_STRINGS, HASHCTL::hcxt, i, INIT_CATS, HASHCTL::keysize, MAX_CATNAME_LEN, MemoryContextSwitchTo(), TupleDescData::natts, palloc(), SPI_connect(), SPI_execute(), SPI_finish(), SPI_getvalue(), SPI_OK_FINISH, SPI_OK_SELECT, SPI_processed, SPI_tuptable, SPITupleTable::tupdesc, and SPITupleTable::vals.

Referenced by crosstab_hash().

normal_rand()

Datum normal_rand

(

PG_FUNCTION_ARGS

)

Definition at line 173 of file tablefunc.c.

{
    FuncCallContext *funcctx;
    uint64      call_cntr;
    uint64      max_calls;
    normal_rand_fctx *fctx;
    float8      mean;
    float8      stddev;
    float8      carry_val;
    bool        use_carry;
    MemoryContext oldcontext;
 
    /* stuff done only on the first call of the function */
    if (SRF_IS_FIRSTCALL())
    {
        int32       num_tuples;
 
        /* create a function context for cross-call persistence */
        funcctx = SRF_FIRSTCALL_INIT();
 
        /*
         * switch to memory context appropriate for multiple function calls
         */
        oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
 
        /* total number of tuples to be returned */
        num_tuples = PG_GETARG_INT32(0);
        if (num_tuples < 0)
            ereport(ERROR,
                    (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                     errmsg("number of rows cannot be negative")));
        funcctx->max_calls = num_tuples;
 
        /* allocate memory for user context */
        fctx = (normal_rand_fctx *) palloc(sizeof(normal_rand_fctx));
 
        /*
         * Use fctx to keep track of upper and lower bounds from call to call.
         * It will also be used to carry over the spare value we get from the
         * Box-Muller algorithm so that we only actually calculate a new value
         * every other call.
         */
        fctx->mean = PG_GETARG_FLOAT8(1);
        fctx->stddev = PG_GETARG_FLOAT8(2);
        fctx->carry_val = 0;
        fctx->use_carry = false;
 
        funcctx->user_fctx = fctx;
 
        MemoryContextSwitchTo(oldcontext);
    }
 
    /* stuff done on every call of the function */
    funcctx = SRF_PERCALL_SETUP();
 
    call_cntr = funcctx->call_cntr;
    max_calls = funcctx->max_calls;
    fctx = funcctx->user_fctx;
    mean = fctx->mean;
    stddev = fctx->stddev;
    carry_val = fctx->carry_val;
    use_carry = fctx->use_carry;
 
    if (call_cntr < max_calls)  /* do when there is more left to send */
    {
        float8      result;
 
        if (use_carry)
        {
            /*
             * reset use_carry and use second value obtained on last pass
             */
            fctx->use_carry = false;
            result = carry_val;
        }
        else
        {
            float8      normval_1;
            float8      normval_2;
 
            /* Get the next two normal values */
            get_normal_pair(&normval_1, &normval_2);
 
            /* use the first */
            result = mean + (stddev * normval_1);
 
            /* and save the second */
            fctx->carry_val = mean + (stddev * normval_2);
            fctx->use_carry = true;
        }
 
        /* send the result */
        SRF_RETURN_NEXT(funcctx, Float8GetDatum(result));
    }
    else
        /* do when there is no more left */
        SRF_RETURN_DONE(funcctx);
}

References FuncCallContext::call_cntr, normal_rand_fctx::carry_val, ereport, errcode(), errmsg(), ERROR, Float8GetDatum(), get_normal_pair(), FuncCallContext::max_calls, normal_rand_fctx::mean, MemoryContextSwitchTo(), FuncCallContext::multi_call_memory_ctx, palloc(), PG_GETARG_FLOAT8, PG_GETARG_INT32, SRF_FIRSTCALL_INIT, SRF_IS_FIRSTCALL, SRF_PERCALL_SETUP, SRF_RETURN_DONE, SRF_RETURN_NEXT, normal_rand_fctx::stddev, normal_rand_fctx::use_carry, and FuncCallContext::user_fctx.

PG_FUNCTION_INFO_V1() [1/5]

PG_FUNCTION_INFO_V1

(

connectby_text

)

PG_FUNCTION_INFO_V1() [2/5]

PG_FUNCTION_INFO_V1

(

connectby_text_serial

)

PG_FUNCTION_INFO_V1() [3/5]

PG_FUNCTION_INFO_V1

(

crosstab

)

PG_FUNCTION_INFO_V1() [4/5]

PG_FUNCTION_INFO_V1

(

crosstab_hash

)

PG_FUNCTION_INFO_V1() [5/5]

PG_FUNCTION_INFO_V1

(

normal_rand

)

validateConnectbyTupleDesc()

static void validateConnectbyTupleDesc ( TupleDesc  td, bool  show_branch, bool  show_serial  )

static

Definition at line 1423 of file tablefunc.c.

{
    int         serial_column = 0;
 
    if (show_serial)
        serial_column = 1;
 
    /* are there the correct number of columns */
    if (show_branch)
    {
        if (td->natts != (CONNECTBY_NCOLS + serial_column))
            ereport(ERROR,
                    (errcode(ERRCODE_DATATYPE_MISMATCH),
                     errmsg("invalid return type"),
                     errdetail("Query-specified return tuple has " \
                               "wrong number of columns.")));
    }
    else
    {
        if (td->natts != CONNECTBY_NCOLS_NOBRANCH + serial_column)
            ereport(ERROR,
                    (errcode(ERRCODE_DATATYPE_MISMATCH),
                     errmsg("invalid return type"),
                     errdetail("Query-specified return tuple has " \
                               "wrong number of columns.")));
    }
 
    /* check that the types of the first two columns match */
    if (TupleDescAttr(td, 0)->atttypid != TupleDescAttr(td, 1)->atttypid)
        ereport(ERROR,
                (errcode(ERRCODE_DATATYPE_MISMATCH),
                 errmsg("invalid return type"),
                 errdetail("First two columns must be the same type.")));
 
    /* check that the type of the third column is INT4 */
    if (TupleDescAttr(td, 2)->atttypid != INT4OID)
        ereport(ERROR,
                (errcode(ERRCODE_DATATYPE_MISMATCH),
                 errmsg("invalid return type"),
                 errdetail("Third column must be type %s.",
                           format_type_be(INT4OID))));
 
    /* check that the type of the fourth column is TEXT if applicable */
    if (show_branch && TupleDescAttr(td, 3)->atttypid != TEXTOID)
        ereport(ERROR,
                (errcode(ERRCODE_DATATYPE_MISMATCH),
                 errmsg("invalid return type"),
                 errdetail("Fourth column must be type %s.",
                           format_type_be(TEXTOID))));
 
    /* check that the type of the fifth column is INT4 */
    if (show_branch && show_serial &&
        TupleDescAttr(td, 4)->atttypid != INT4OID)
        ereport(ERROR,
                (errcode(ERRCODE_DATATYPE_MISMATCH),
                 errmsg("query-specified return tuple not valid for Connectby: "
                        "fifth column must be type %s",
                        format_type_be(INT4OID))));
 
    /* check that the type of the fourth column is INT4 */
    if (!show_branch && show_serial &&
        TupleDescAttr(td, 3)->atttypid != INT4OID)
        ereport(ERROR,
                (errcode(ERRCODE_DATATYPE_MISMATCH),
                 errmsg("query-specified return tuple not valid for Connectby: "
                        "fourth column must be type %s",
                        format_type_be(INT4OID))));
 
    /* OK, the tupdesc is valid for our purposes */
}

References CONNECTBY_NCOLS, CONNECTBY_NCOLS_NOBRANCH, ereport, errcode(), errdetail(), errmsg(), ERROR, format_type_be(), TupleDescData::natts, and TupleDescAttr.

Referenced by connectby_text(), and connectby_text_serial().

Variable Documentation

PG_MODULE_MAGIC

PG_MODULE_MAGIC

Definition at line 47 of file tablefunc.c.