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tablefunc.c
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/*
* contrib/tablefunc/tablefunc.c
*
*
* tablefunc
*
* Sample to demonstrate C functions which return setof scalar
* and setof composite.
* Joe Conway <mail@joeconway.com>
* And contributors:
* Nabil Sayegh <postgresql@e-trolley.de>
*
* Copyright (c) 2002-2019, PostgreSQL Global Development Group
*
* Permission to use, copy, modify, and distribute this software and its
* documentation for any purpose, without fee, and without a written agreement
* is hereby granted, provided that the above copyright notice and this
* paragraph and the following two paragraphs appear in all copies.
*
* IN NO EVENT SHALL THE AUTHORS OR DISTRIBUTORS BE LIABLE TO ANY PARTY FOR
* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING
* LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS
* DOCUMENTATION, EVEN IF THE AUTHOR OR DISTRIBUTORS HAVE BEEN ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* THE AUTHORS AND DISTRIBUTORS SPECIFICALLY DISCLAIM ANY WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
* ON AN "AS IS" BASIS, AND THE AUTHOR AND DISTRIBUTORS HAS NO OBLIGATIONS TO
* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
*
*/
#include "postgres.h"
#include <math.h>
#include "access/htup_details.h"
#include "catalog/pg_type.h"
#include "executor/spi.h"
#include "funcapi.h"
#include "lib/stringinfo.h"
#include "miscadmin.h"
#include "utils/builtins.h"
#include "tablefunc.h"
PG_MODULE_MAGIC;
static HTAB *load_categories_hash(char *cats_sql, MemoryContext per_query_ctx);
static Tuplestorestate *get_crosstab_tuplestore(char *sql,
HTAB *crosstab_hash,
TupleDesc tupdesc,
MemoryContext per_query_ctx,
bool randomAccess);
static void validateConnectbyTupleDesc(TupleDesc tupdesc, bool show_branch, bool show_serial);
static bool compatCrosstabTupleDescs(TupleDesc tupdesc1, TupleDesc tupdesc2);
static void compatConnectbyTupleDescs(TupleDesc tupdesc1, TupleDesc tupdesc2);
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);
typedef struct
{
float8 mean; /* mean of the distribution */
float8 stddev; /* stddev of the distribution */
float8 carry_val; /* hold second generated value */
bool use_carry; /* use second generated value */
} normal_rand_fctx;
#define xpfree(var_) \
do { \
if (var_ != NULL) \
{ \
pfree(var_); \
var_ = NULL; \
} \
} while (0)
#define xpstrdup(tgtvar_, srcvar_) \
do { \
if (srcvar_) \
tgtvar_ = pstrdup(srcvar_); \
else \
tgtvar_ = NULL; \
} while (0)
#define xstreq(tgtvar_, srcvar_) \
(((tgtvar_ == NULL) && (srcvar_ == NULL)) || \
((tgtvar_ != NULL) && (srcvar_ != NULL) && (strcmp(tgtvar_, srcvar_) == 0)))
/* sign, 10 digits, '\0' */
#define INT32_STRLEN 12
/* stored info for a crosstab category */
typedef struct crosstab_cat_desc
{
char *catname; /* full category name */
uint64 attidx; /* zero based */
} crosstab_cat_desc;
#define MAX_CATNAME_LEN NAMEDATALEN
#define INIT_CATS 64
#define crosstab_HashTableLookup(HASHTAB, CATNAME, CATDESC) \
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)
#define crosstab_HashTableInsert(HASHTAB, CATDESC) \
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)
/* hash table */
typedef struct crosstab_hashent
{
char internal_catname[MAX_CATNAME_LEN];
crosstab_cat_desc *catdesc;
} crosstab_HashEnt;
/*
* normal_rand - return requested number of random values
* with a Gaussian (Normal) distribution.
*
* inputs are int numvals, float8 mean, and float8 stddev
* returns setof float8
*/
PG_FUNCTION_INFO_V1(normal_rand);
Datum
normal_rand(PG_FUNCTION_ARGS)
{
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())
{
/* 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 */
funcctx->max_calls = PG_GETARG_UINT32(0);
/* 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);
}
/*
* get_normal_pair()
* Assigns normally distributed (Gaussian) values to a pair of provided
* parameters, with mean 0, standard deviation 1.
*
* This routine implements Algorithm P (Polar method for normal deviates)
* from Knuth's _The_Art_of_Computer_Programming_, Volume 2, 3rd ed., pages
* 122-126. Knuth cites his source as "The polar method", G. E. P. Box, M. E.
* Muller, and G. Marsaglia, _Annals_Math,_Stat._ 29 (1958), 610-611.
*
*/
static void
get_normal_pair(float8 *x1, float8 *x2)
{
float8 u1,
u2,
v1,
v2,
s;
do
{
u1 = (float8) random() / (float8) MAX_RANDOM_VALUE;
u2 = (float8) random() / (float8) MAX_RANDOM_VALUE;
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;
}
}
/*
* crosstab - create a crosstab of rowids and values columns from a
* SQL statement returning one rowid column, one category column,
* and one value column.
*
* e.g. given sql which produces:
*
* rowid cat value
* ------+-------+-------
* row1 cat1 val1
* row1 cat2 val2
* row1 cat3 val3
* row1 cat4 val4
* row2 cat1 val5
* row2 cat2 val6
* row2 cat3 val7
* row2 cat4 val8
*
* crosstab returns:
* <===== values columns =====>
* rowid cat1 cat2 cat3 cat4
* ------+-------+-------+-------+-------
* row1 val1 val2 val3 val4
* row2 val5 val6 val7 val8
*
* NOTES:
* 1. SQL result must be ordered by 1,2.
* 2. The number of values columns depends on the tuple description
* of the function's declared return type. The return type's columns
* must match the datatypes of the SQL query's result. The datatype
* of the category column can be anything, however.
* 3. Missing values (i.e. not enough adjacent rows of same rowid to
* fill the number of result values columns) are filled in with nulls.
* 4. Extra values (i.e. too many adjacent rows of same rowid to fill
* the number of result values columns) are skipped.
* 5. Rows with all nulls in the values columns are skipped.
*/
PG_FUNCTION_INFO_V1(crosstab);
Datum
crosstab(PG_FUNCTION_ARGS)
{
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;
}
/*
* crosstab_hash - reimplement crosstab as materialized function and
* properly deal with missing values (i.e. don't pack remaining
* values to the left)
*
* crosstab - create a crosstab of rowids and values columns from a
* SQL statement returning one rowid column, one category column,
* and one value column.
*
* e.g. given sql which produces:
*
* rowid cat value
* ------+-------+-------
* row1 cat1 val1
* row1 cat2 val2
* row1 cat4 val4
* row2 cat1 val5
* row2 cat2 val6
* row2 cat3 val7
* row2 cat4 val8
*
* crosstab returns:
* <===== values columns =====>
* rowid cat1 cat2 cat3 cat4
* ------+-------+-------+-------+-------
* row1 val1 val2 null val4
* row2 val5 val6 val7 val8
*
* NOTES:
* 1. SQL result must be ordered by 1.
* 2. The number of values columns depends on the tuple description
* of the function's declared return type.
* 3. Missing values (i.e. missing category) are filled in with nulls.
* 4. Extra values (i.e. not in category results) are skipped.
*/
PG_FUNCTION_INFO_V1(crosstab_hash);
Datum
crosstab_hash(PG_FUNCTION_ARGS)
{
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,
per_query_ctx,
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;
}
/*
* load up the categories hash table
*/
static HTAB *
load_categories_hash(char *cats_sql, MemoryContext per_query_ctx)
{
HTAB *crosstab_hash;
HASHCTL ctl;
int ret;
uint64 proc;
MemoryContext SPIcontext;
/* initialize the category hash table */
MemSet(&ctl, 0, sizeof(ctl));
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_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);
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;
}
/*
* create and populate the crosstab tuplestore using the provided source query
*/
static Tuplestorestate *
get_crosstab_tuplestore(char *sql,
HTAB *crosstab_hash,
TupleDesc tupdesc,
MemoryContext per_query_ctx,
bool randomAccess)
{
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 */
values = (char **) palloc(result_ncols * sizeof(char *));
/* and make sure it's clear */
memset(values, '\0', 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");
tuplestore_donestoring(tupstore);
return tupstore;
}
/*
* connectby_text - produce a result set from a hierarchical (parent/child)
* table.
*
* e.g. given table foo:
*
* keyid parent_keyid pos
* ------+------------+--
* row1 NULL 0
* row2 row1 0
* row3 row1 0
* row4 row2 1
* row5 row2 0
* row6 row4 0
* row7 row3 0
* row8 row6 0
* row9 row5 0
*
*
* connectby(text relname, text keyid_fld, text parent_keyid_fld
* [, text orderby_fld], text start_with, int max_depth
* [, text branch_delim])
* connectby('foo', 'keyid', 'parent_keyid', 'pos', 'row2', 0, '~') returns:
*
* keyid parent_id level branch serial
* ------+-----------+--------+-----------------------
* row2 NULL 0 row2 1
* row5 row2 1 row2~row5 2
* row9 row5 2 row2~row5~row9 3
* row4 row2 1 row2~row4 4
* row6 row4 2 row2~row4~row6 5
* row8 row6 3 row2~row4~row6~row8 6
*
*/
PG_FUNCTION_INFO_V1(connectby_text);
#define CONNECTBY_NCOLS 4
#define CONNECTBY_NCOLS_NOBRANCH 3
Datum
connectby_text(PG_FUNCTION_ARGS)
{
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;