Hi
I propose new function string_to_table. This function is significantly
faster (and simpler) variant of regexp_split_to_array function. There was
same process years ago when we implemented string_agg as faster variant of
array_to_string(array_agg()). string_to_table is faster variant (and little
bit more intuitive alternative of unnest(string_to_array()).
string_to_table is about 15% faster than unnest(string_to_array()) and
about 40% faster than regexp_split_to_array.
Initial patch is attached
Notes, comments?
Regards
Pavel
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7a270eb0ab..4046646267 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -14160,6 +14160,9 @@ SELECT NULLIF(value, '(none)') ...
<indexterm>
<primary>string_to_array</primary>
</indexterm>
+ <indexterm>
+ <primary>string_to_table</primary>
+ </indexterm>
<indexterm>
<primary>unnest</primary>
</indexterm>
@@ -14362,6 +14365,22 @@ SELECT NULLIF(value, '(none)') ...
<entry><literal>string_to_array('xx~^~yy~^~zz', '~^~', 'yy')</literal></entry>
<entry><literal>{xx,NULL,zz}</literal></entry>
</row>
+
+
+ <row>
+ <entry>
+ <literal>
+ <function>string_to_table</function>(<type>text</type>, <type>text</type> <optional>, <type>text</type></optional>)
+ </literal>
+ </entry>
+ <entry><type>setof text</type></entry>
+ <entry>splits string into table using supplied delimiter and
+ optional null string</entry>
+ <entry><literal>string_to_table('xx~^~yy~^~zz', '~^~', 'yy')</literal></entry>
+ <entry><literallayout class="monospaced">xx
+yy
+zz</literallayout>(3 rows)</entry>
+ </row>
<row>
<entry>
<literal>
diff --git a/src/backend/utils/adt/varlena.c b/src/backend/utils/adt/varlena.c
index 2eaabd6231..5d0826e668 100644
--- a/src/backend/utils/adt/varlena.c
+++ b/src/backend/utils/adt/varlena.c
@@ -26,6 +26,7 @@
#include "lib/hyperloglog.h"
#include "libpq/pqformat.h"
#include "miscadmin.h"
+#include "nodes/execnodes.h"
#include "parser/scansup.h"
#include "port/pg_bswap.h"
#include "regex/regex.h"
@@ -35,6 +36,7 @@
#include "utils/memutils.h"
#include "utils/pg_locale.h"
#include "utils/sortsupport.h"
+#include "utils/tuplestore.h"
#include "utils/varlena.h"
@@ -92,6 +94,16 @@ typedef struct
pg_locale_t locale;
} VarStringSortSupport;
+/*
+ * Holds target metadata used for split string to array or to table.
+ */
+typedef struct
+{
+ ArrayBuildState *astate;
+ Tuplestorestate *tupstore;
+ TupleDesc tupdesc;
+} SplitStringTargetData;
+
/*
* This should be large enough that most strings will fit, but small enough
* that we feel comfortable putting it on the stack
@@ -139,7 +151,7 @@ static bytea *bytea_substring(Datum str,
bool length_not_specified);
static bytea *bytea_overlay(bytea *t1, bytea *t2, int sp, int sl);
static void appendStringInfoText(StringInfo str, const text *t);
-static Datum text_to_array_internal(PG_FUNCTION_ARGS);
+static bool text_to_array_internal(FunctionCallInfo fcinfo, SplitStringTargetData *tstate);
static text *array_to_text_internal(FunctionCallInfo fcinfo, ArrayType *v,
const char *fldsep, const char *null_string);
static StringInfo makeStringAggState(FunctionCallInfo fcinfo);
@@ -4679,7 +4691,19 @@ text_isequal(text *txt1, text *txt2, Oid collid)
Datum
text_to_array(PG_FUNCTION_ARGS)
{
- return text_to_array_internal(fcinfo);
+ SplitStringTargetData tstate;
+
+ /* reset tstate */
+ memset(&tstate, 0, sizeof(tstate));
+
+ if (!text_to_array_internal(fcinfo, &tstate))
+ PG_RETURN_NULL();
+
+ if (!tstate.astate)
+ PG_RETURN_ARRAYTYPE_P(construct_empty_array(TEXTOID));
+
+ PG_RETURN_ARRAYTYPE_P(makeArrayResult(tstate.astate,
+ CurrentMemoryContext));
}
/*
@@ -4693,16 +4717,98 @@ text_to_array(PG_FUNCTION_ARGS)
Datum
text_to_array_null(PG_FUNCTION_ARGS)
{
- return text_to_array_internal(fcinfo);
+ return text_to_array(fcinfo);
+}
+
+/*
+ * text_to_table
+ * Parse input string and returns substrings as a table.
+ */
+Datum
+text_to_table(PG_FUNCTION_ARGS)
+{
+ ReturnSetInfo *rsi = (ReturnSetInfo *) fcinfo->resultinfo;
+ SplitStringTargetData tstate;
+ MemoryContext old_cxt;
+
+ /* check to see if caller supports us returning a tuplestore */
+ if (rsi == NULL || !IsA(rsi, ReturnSetInfo))
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("set-valued function called in context that cannot accept a set")));
+
+ if (!(rsi->allowedModes & SFRM_Materialize))
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("materialize mode required, but it is not "
+ "allowed in this context")));
+
+ old_cxt = MemoryContextSwitchTo(rsi->econtext->ecxt_per_query_memory);
+
+ tstate.astate = NULL;
+ tstate.tupdesc = CreateTupleDescCopy(rsi->expectedDesc);
+ tstate.tupstore = tuplestore_begin_heap(rsi->allowedModes & SFRM_Materialize_Random,
+ false, work_mem);
+
+ MemoryContextSwitchTo(old_cxt);
+
+ (void) text_to_array_internal(fcinfo, &tstate);
+
+ tuplestore_donestoring(tstate.tupstore);
+
+ rsi->returnMode = SFRM_Materialize;
+ rsi->setResult = tstate.tupstore;
+ rsi->setDesc = tstate.tupdesc;
+
+ return (Datum) 0;
+}
+
+Datum
+text_to_table_null(PG_FUNCTION_ARGS)
+{
+ return text_to_table(fcinfo);
+}
+
+/*
+ * Add text to result set (table or array). Build a table when set is a expected or build
+ * a array
+ */
+static void
+accum_result(SplitStringTargetData *tstate,
+ text *result_text,
+ bool is_null)
+{
+ if (tstate->tupdesc)
+ {
+ HeapTuple tuple;
+ Datum values[1];
+ bool nulls[1];
+
+ values[0] = PointerGetDatum(result_text);
+ nulls[0] = is_null;
+
+ tuple = heap_form_tuple(tstate->tupdesc, values, nulls);
+ tuplestore_puttuple(tstate->tupstore, tuple);
+ }
+ else
+ {
+ tstate->astate = accumArrayResult(tstate->astate,
+ PointerGetDatum(result_text),
+ is_null,
+ TEXTOID,
+ CurrentMemoryContext);
+ }
}
/*
* common code for text_to_array and text_to_array_null functions
*
* These are not strict so we have to test for null inputs explicitly.
+ * Returns false, when result is null, else returns true.
+ *
*/
-static Datum
-text_to_array_internal(PG_FUNCTION_ARGS)
+static bool
+text_to_array_internal(FunctionCallInfo fcinfo, SplitStringTargetData *tstate)
{
text *inputstring;
text *fldsep;
@@ -4712,11 +4818,10 @@ text_to_array_internal(PG_FUNCTION_ARGS)
char *start_ptr;
text *result_text;
bool is_null;
- ArrayBuildState *astate = NULL;
/* when input string is NULL, then result is NULL too */
if (PG_ARGISNULL(0))
- PG_RETURN_NULL();
+ return false;
inputstring = PG_GETARG_TEXT_PP(0);
@@ -4745,7 +4850,7 @@ text_to_array_internal(PG_FUNCTION_ARGS)
/* return empty array for empty input string */
if (inputstring_len < 1)
- PG_RETURN_ARRAYTYPE_P(construct_empty_array(TEXTOID));
+ return true;
/*
* empty field separator: return the input string as a one-element
@@ -4753,22 +4858,11 @@ text_to_array_internal(PG_FUNCTION_ARGS)
*/
if (fldsep_len < 1)
{
- Datum elems[1];
- bool nulls[1];
- int dims[1];
- int lbs[1];
-
/* single element can be a NULL too */
is_null = null_string ? text_isequal(inputstring, null_string, PG_GET_COLLATION()) : false;
- elems[0] = PointerGetDatum(inputstring);
- nulls[0] = is_null;
- dims[0] = 1;
- lbs[0] = 1;
- /* XXX: this hardcodes assumptions about the text type */
- PG_RETURN_ARRAYTYPE_P(construct_md_array(elems, nulls,
- 1, dims, lbs,
- TEXTOID, -1, false, TYPALIGN_INT));
+ accum_result(tstate, inputstring, is_null);
+ return true;
}
text_position_setup(inputstring, fldsep, PG_GET_COLLATION(), &state);
@@ -4802,12 +4896,7 @@ text_to_array_internal(PG_FUNCTION_ARGS)
is_null = null_string ? text_isequal(result_text, null_string, PG_GET_COLLATION()) : false;
/* stash away this field */
- astate = accumArrayResult(astate,
- PointerGetDatum(result_text),
- is_null,
- TEXTOID,
- CurrentMemoryContext);
-
+ accum_result(tstate, result_text, is_null);
pfree(result_text);
if (!found)
@@ -4844,12 +4933,7 @@ text_to_array_internal(PG_FUNCTION_ARGS)
is_null = null_string ? text_isequal(result_text, null_string, PG_GET_COLLATION()) : false;
/* stash away this field */
- astate = accumArrayResult(astate,
- PointerGetDatum(result_text),
- is_null,
- TEXTOID,
- CurrentMemoryContext);
-
+ accum_result(tstate, result_text, is_null);
pfree(result_text);
start_ptr += chunk_len;
@@ -4857,8 +4941,7 @@ text_to_array_internal(PG_FUNCTION_ARGS)
}
}
- PG_RETURN_ARRAYTYPE_P(makeArrayResult(astate,
- CurrentMemoryContext));
+ return true;
}
/*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 4bce3ad8de..2fc97f830f 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -3561,6 +3561,14 @@
{ oid => '2768', descr => 'split string by pattern',
proname => 'regexp_split_to_array', prorettype => '_text',
proargtypes => 'text text text', prosrc => 'regexp_split_to_array' },
+{ oid => '2228', descr => 'split delimited text',
+ proname => 'string_to_table', prorows => '1000', proretset => 't',
+ prorettype => 'text', proargtypes => 'text text',
+ prosrc => 'text_to_table' },
+{ oid => '2282', descr => 'split delimited text with null string',
+ proname => 'string_to_table', prorows => '1000', proretset => 't',
+ prorettype => 'text', proargtypes => 'text text text',
+ prosrc => 'text_to_table_null' },
{ oid => '2089', descr => 'convert int4 number to hex',
proname => 'to_hex', prorettype => 'text', proargtypes => 'int4',
prosrc => 'to_hex32' },
diff --git a/src/test/regress/expected/arrays.out b/src/test/regress/expected/arrays.out
index c730563f03..f024b153cc 100644
--- a/src/test/regress/expected/arrays.out
+++ b/src/test/regress/expected/arrays.out
@@ -1755,6 +1755,109 @@ select string_to_array('1,2,3,4,*,6', ',', '*');
{1,2,3,4,NULL,6}
(1 row)
+select string_to_table('1|2|3', '|');
+ string_to_table
+-----------------
+ 1
+ 2
+ 3
+(3 rows)
+
+select string_to_table('1|2|3|', '|');
+ string_to_table
+-----------------
+ 1
+ 2
+ 3
+
+(4 rows)
+
+select string_to_table('1||2|3||', '||');
+ string_to_table
+-----------------
+ 1
+ 2|3
+
+(3 rows)
+
+select string_to_table('1|2|3', '');
+ string_to_table
+-----------------
+ 1|2|3
+(1 row)
+
+select string_to_table('', '|');
+ string_to_table
+-----------------
+(0 rows)
+
+select string_to_table('1|2|3', NULL);
+ string_to_table
+-----------------
+(0 rows)
+
+select string_to_table(NULL, '|') IS NULL;
+ ?column?
+----------
+(0 rows)
+
+select string_to_table('abc', '');
+ string_to_table
+-----------------
+ abc
+(1 row)
+
+select string_to_table('abc', '', 'abc');
+ string_to_table
+-----------------
+
+(1 row)
+
+select string_to_table('abc', ',');
+ string_to_table
+-----------------
+ abc
+(1 row)
+
+select string_to_table('abc', ',', 'abc');
+ string_to_table
+-----------------
+
+(1 row)
+
+select string_to_table('1,2,3,4,,6', ',');
+ string_to_table
+-----------------
+ 1
+ 2
+ 3
+ 4
+
+ 6
+(6 rows)
+
+select string_to_table('1,2,3,4,,6', ',', '');
+ string_to_table
+-----------------
+ 1
+ 2
+ 3
+ 4
+
+ 6
+(6 rows)
+
+select string_to_table('1,2,3,4,*,6', ',', '*');
+ string_to_table
+-----------------
+ 1
+ 2
+ 3
+ 4
+
+ 6
+(6 rows)
+
select array_to_string(NULL::int4[], ',') IS NULL;
?column?
----------
diff --git a/src/test/regress/sql/arrays.sql b/src/test/regress/sql/arrays.sql
index 25dd4e2c6d..d57352cf47 100644
--- a/src/test/regress/sql/arrays.sql
+++ b/src/test/regress/sql/arrays.sql
@@ -544,6 +544,21 @@ select string_to_array('1,2,3,4,,6', ',');
select string_to_array('1,2,3,4,,6', ',', '');
select string_to_array('1,2,3,4,*,6', ',', '*');
+select string_to_table('1|2|3', '|');
+select string_to_table('1|2|3|', '|');
+select string_to_table('1||2|3||', '||');
+select string_to_table('1|2|3', '');
+select string_to_table('', '|');
+select string_to_table('1|2|3', NULL);
+select string_to_table(NULL, '|') IS NULL;
+select string_to_table('abc', '');
+select string_to_table('abc', '', 'abc');
+select string_to_table('abc', ',');
+select string_to_table('abc', ',', 'abc');
+select string_to_table('1,2,3,4,,6', ',');
+select string_to_table('1,2,3,4,,6', ',', '');
+select string_to_table('1,2,3,4,*,6', ',', '*');
+
select array_to_string(NULL::int4[], ',') IS NULL;
select array_to_string('{}'::int4[], ',');
select array_to_string(array[1,2,3,4,NULL,6], ',');
