postgres.git - commit 0c882a298881

postgres.git / summary / log / commit / refs

commit    0c882a298881056176a27ccc44c5c3bb7c8f308c
Author:   David Rowley <drowley@postgresql.org>
Date:     Thu Oct 26 21:41:55 2023 +0000
First released in: 17.0

    Optimize various aggregate deserialization functions, take 2
    
    f0efa5aec added initReadOnlyStringInfo to allow a StringInfo to be
    initialized from an existing buffer and also relaxed the requirement
    that a StringInfo's buffer must be NUL terminated at data[len].  Now
    that we have that, there's no need for these aggregate deserial
    functions to use appendBinaryStringInfo() as that rather wastefully
    palloc'd a new buffer and memcpy'd in the bytea's buffer.  Instead, we can
    just use the bytea's buffer and point the StringInfo directly to that
    using the new initializer function.
    
    In Amdahl's law, this speeds up the serial portion of parallel
    aggregates and makes sum(numeric), avg(numeric), var_pop(numeric),
    var_samp(numeric), variance(numeric), stddev_pop(numeric),
    stddev_samp(numeric), stddev(numeric), array_agg(anyarray),
    string_agg(text) and string_agg(bytea) scale better in parallel queries.
    
    Author: David Rowley
    Discussion: https://postgr.es/m/CAApHDvr%3De-YOigriSHHm324a40HPqcUhSp6pWWgjz5WwegR%3DcQ%40mail.gmail.com


 src/backend/utils/adt/array_userfuncs.c | 20 +++++++----------
 src/backend/utils/adt/numeric.c         | 40 +++++++++++++--------------------
 src/backend/utils/adt/varlena.c         | 10 ++++-----
 3 files changed, 28 insertions(+), 42 deletions(-)

diff --git a/src/backend/utils/adt/array_userfuncs.c b/src/backend/utils/adt/array_userfuncs.c
index c831a9395c6..57bd7e82bc4 100644
--- a/src/backend/utils/adt/array_userfuncs.c
+++ b/src/backend/utils/adt/array_userfuncs.c
@@ -723,12 +723,11 @@ array_agg_deserialize(PG_FUNCTION_ARGS)
 	sstate = PG_GETARG_BYTEA_PP(0);
 
 	/*
-	 * Copy the bytea into a StringInfo so that we can "receive" it using the
-	 * standard recv-function infrastructure.
+	 * Initialize a StringInfo so that we can "receive" it using the standard
+	 * recv-function infrastructure.
 	 */
-	initStringInfo(&buf);
-	appendBinaryStringInfo(&buf,
-						   VARDATA_ANY(sstate), VARSIZE_ANY_EXHDR(sstate));
+	initReadOnlyStringInfo(&buf, VARDATA_ANY(sstate),
+						   VARSIZE_ANY_EXHDR(sstate));
 
 	/* element_type */
 	element_type = pq_getmsgint(&buf, 4);
@@ -815,7 +814,6 @@ array_agg_deserialize(PG_FUNCTION_ARGS)
 	}
 
 	pq_getmsgend(&buf);
-	pfree(buf.data);
 
 	PG_RETURN_POINTER(result);
 }
@@ -1124,12 +1122,11 @@ array_agg_array_deserialize(PG_FUNCTION_ARGS)
 	sstate = PG_GETARG_BYTEA_PP(0);
 
 	/*
-	 * Copy the bytea into a StringInfo so that we can "receive" it using the
-	 * standard recv-function infrastructure.
+	 * Initialize a StringInfo so that we can "receive" it using the standard
+	 * recv-function infrastructure.
 	 */
-	initStringInfo(&buf);
-	appendBinaryStringInfo(&buf,
-						   VARDATA_ANY(sstate), VARSIZE_ANY_EXHDR(sstate));
+	initReadOnlyStringInfo(&buf, VARDATA_ANY(sstate),
+						   VARSIZE_ANY_EXHDR(sstate));
 
 	/* element_type */
 	element_type = pq_getmsgint(&buf, 4);
@@ -1187,7 +1184,6 @@ array_agg_array_deserialize(PG_FUNCTION_ARGS)
 	memcpy(result->lbs, temp, sizeof(result->lbs));
 
 	pq_getmsgend(&buf);
-	pfree(buf.data);
 
 	PG_RETURN_POINTER(result);
 }
diff --git a/src/backend/utils/adt/numeric.c b/src/backend/utils/adt/numeric.c
index 3c3184f15b5..bf61fd7dbc0 100644
--- a/src/backend/utils/adt/numeric.c
+++ b/src/backend/utils/adt/numeric.c
@@ -5190,12 +5190,11 @@ numeric_avg_deserialize(PG_FUNCTION_ARGS)
 	init_var(&tmp_var);
 
 	/*
-	 * Copy the bytea into a StringInfo so that we can "receive" it using the
-	 * standard recv-function infrastructure.
+	 * Initialize a StringInfo so that we can "receive" it using the standard
+	 * recv-function infrastructure.
 	 */
-	initStringInfo(&buf);
-	appendBinaryStringInfo(&buf,
-						   VARDATA_ANY(sstate), VARSIZE_ANY_EXHDR(sstate));
+	initReadOnlyStringInfo(&buf, VARDATA_ANY(sstate),
+						   VARSIZE_ANY_EXHDR(sstate));
 
 	result = makeNumericAggStateCurrentContext(false);
 
@@ -5222,7 +5221,6 @@ numeric_avg_deserialize(PG_FUNCTION_ARGS)
 	result->nInfcount = pq_getmsgint64(&buf);
 
 	pq_getmsgend(&buf);
-	pfree(buf.data);
 
 	free_var(&tmp_var);
 
@@ -5306,12 +5304,11 @@ numeric_deserialize(PG_FUNCTION_ARGS)
 	init_var(&tmp_var);
 
 	/*
-	 * Copy the bytea into a StringInfo so that we can "receive" it using the
-	 * standard recv-function infrastructure.
+	 * Initialize a StringInfo so that we can "receive" it using the standard
+	 * recv-function infrastructure.
 	 */
-	initStringInfo(&buf);
-	appendBinaryStringInfo(&buf,
-						   VARDATA_ANY(sstate), VARSIZE_ANY_EXHDR(sstate));
+	initReadOnlyStringInfo(&buf, VARDATA_ANY(sstate),
+						   VARSIZE_ANY_EXHDR(sstate));
 
 	result = makeNumericAggStateCurrentContext(false);
 
@@ -5342,7 +5339,6 @@ numeric_deserialize(PG_FUNCTION_ARGS)
 	result->nInfcount = pq_getmsgint64(&buf);
 
 	pq_getmsgend(&buf);
-	pfree(buf.data);
 
 	free_var(&tmp_var);
 
@@ -5677,12 +5673,11 @@ numeric_poly_deserialize(PG_FUNCTION_ARGS)
 	init_var(&tmp_var);
 
 	/*
-	 * Copy the bytea into a StringInfo so that we can "receive" it using the
-	 * standard recv-function infrastructure.
+	 * Initialize a StringInfo so that we can "receive" it using the standard
+	 * recv-function infrastructure.
 	 */
-	initStringInfo(&buf);
-	appendBinaryStringInfo(&buf,
-						   VARDATA_ANY(sstate), VARSIZE_ANY_EXHDR(sstate));
+	initReadOnlyStringInfo(&buf, VARDATA_ANY(sstate),
+						   VARSIZE_ANY_EXHDR(sstate));
 
 	result = makePolyNumAggStateCurrentContext(false);
 
@@ -5706,7 +5701,6 @@ numeric_poly_deserialize(PG_FUNCTION_ARGS)
 #endif
 
 	pq_getmsgend(&buf);
-	pfree(buf.data);
 
 	free_var(&tmp_var);
 
@@ -5868,12 +5862,11 @@ int8_avg_deserialize(PG_FUNCTION_ARGS)
 	init_var(&tmp_var);
 
 	/*
-	 * Copy the bytea into a StringInfo so that we can "receive" it using the
-	 * standard recv-function infrastructure.
+	 * Initialize a StringInfo so that we can "receive" it using the standard
+	 * recv-function infrastructure.
 	 */
-	initStringInfo(&buf);
-	appendBinaryStringInfo(&buf,
-						   VARDATA_ANY(sstate), VARSIZE_ANY_EXHDR(sstate));
+	initReadOnlyStringInfo(&buf, VARDATA_ANY(sstate),
+						   VARSIZE_ANY_EXHDR(sstate));
 
 	result = makePolyNumAggStateCurrentContext(false);
 
@@ -5889,7 +5882,6 @@ int8_avg_deserialize(PG_FUNCTION_ARGS)
 #endif
 
 	pq_getmsgend(&buf);
-	pfree(buf.data);
 
 	free_var(&tmp_var);
 
diff --git a/src/backend/utils/adt/varlena.c b/src/backend/utils/adt/varlena.c
index 72e1e24fe02..ec4e580d7fe 100644
--- a/src/backend/utils/adt/varlena.c
+++ b/src/backend/utils/adt/varlena.c
@@ -5289,12 +5289,11 @@ string_agg_deserialize(PG_FUNCTION_ARGS)
 	sstate = PG_GETARG_BYTEA_PP(0);
 
 	/*
-	 * Copy the bytea into a StringInfo so that we can "receive" it using the
-	 * standard recv-function infrastructure.
+	 * Initialize a StringInfo so that we can "receive" it using the standard
+	 * recv-function infrastructure.
 	 */
-	initStringInfo(&buf);
-	appendBinaryStringInfo(&buf,
-						   VARDATA_ANY(sstate), VARSIZE_ANY_EXHDR(sstate));
+	initReadOnlyStringInfo(&buf, VARDATA_ANY(sstate),
+						   VARSIZE_ANY_EXHDR(sstate));
 
 	result = makeStringAggState(fcinfo);
 
@@ -5307,7 +5306,6 @@ string_agg_deserialize(PG_FUNCTION_ARGS)
 	appendBinaryStringInfo(result, data, datalen);
 
 	pq_getmsgend(&buf);
-	pfree(buf.data);
 
 	PG_RETURN_POINTER(result);
 }


[parent: 26f988212ead]