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Optimize various aggregate deserialization functions

author David Rowley <drowley@postgresql.org>

Mon, 9 Oct 2023 04:25:16 +0000 (17:25 +1300)

committer David Rowley <drowley@postgresql.org>

Mon, 9 Oct 2023 04:25:16 +0000 (17:25 +1300)

The serialized representation of an internal aggregate state is a bytea
value. In each deserial function, in order to "receive" the bytea value
we appended it onto a short-lived StringInfoData using
appendBinaryStringInfo. This was a little wasteful as it meant having to
palloc memory, copy a (possibly long) series of bytes then later pfree
that memory. Instead of going to this extra trouble, we can just fake up
a StringInfoData and point the data directly at the bytea's payload. This
should help increase the performance of internal aggregate
deserialization.

Reviewed-by: Michael Paquier
Discussion: https://postgr.es/m/CAApHDvr=e-YOigriSHHm324a40HPqcUhSp6pWWgjz5WwegR=cQ@mail.gmail.com

src/backend/utils/adt/array_userfuncs.c patch | blob | blame | history

src/backend/utils/adt/numeric.c patch | blob | blame | history

src/backend/utils/adt/varlena.c patch | blob | blame | history

diff --git a/src/backend/utils/adt/array_userfuncs.c b/src/backend/utils/adt/array_userfuncs.c

index 5c4fdcfba4693dcf6d83047806bd62cbe3adfd1d..7f87df45df654f37b159210c42c65b40d02b59cc 100644 (file)

--- a/src/backend/utils/adt/array_userfuncs.c

+++ b/src/backend/utils/adt/array_userfuncs.c

@@ -723,12 +723,13 @@ 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.

+ * Fake up a StringInfo pointing to the bytea's value so we can "receive"

+ * the serialized aggregate state value.

- initStringInfo(&buf);

- appendBinaryStringInfo(&buf,

- VARDATA_ANY(sstate), VARSIZE_ANY_EXHDR(sstate));

+ buf.data = VARDATA_ANY(sstate);

+ buf.len = VARSIZE_ANY_EXHDR(sstate);

+ buf.maxlen = 0;

+ buf.cursor = 0;

/* element_type */

element_type = pq_getmsgint(&buf, 4);

@@ -825,7 +826,6 @@ array_agg_deserialize(PG_FUNCTION_ARGS)

}

pq_getmsgend(&buf);

- pfree(buf.data);

PG_RETURN_POINTER(result);

}

@@ -1134,12 +1134,13 @@ 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.

+ * Fake up a StringInfo pointing to the bytea's value so we can "receive"

+ * the serialized aggregate state value.

- initStringInfo(&buf);

- appendBinaryStringInfo(&buf,

- VARDATA_ANY(sstate), VARSIZE_ANY_EXHDR(sstate));

+ buf.data = VARDATA_ANY(sstate);

+ buf.len = VARSIZE_ANY_EXHDR(sstate);

+ buf.maxlen = 0;

+ buf.cursor = 0;

/* element_type */

element_type = pq_getmsgint(&buf, 4);

@@ -1197,7 +1198,6 @@ 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 3c3184f15b5692341342e2d720a09f906d74fba7..f4b885005fca8c6ef5d4e8b93539c505e2799798 100644 (file)

--- a/src/backend/utils/adt/numeric.c

+++ b/src/backend/utils/adt/numeric.c

@@ -5190,12 +5190,13 @@ 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.

+ * Fake up a StringInfo pointing to the bytea's value so we can "receive"

+ * the serialized aggregate state value.

- initStringInfo(&buf);

- appendBinaryStringInfo(&buf,

- VARDATA_ANY(sstate), VARSIZE_ANY_EXHDR(sstate));

+ buf.data = VARDATA_ANY(sstate);

+ buf.len = VARSIZE_ANY_EXHDR(sstate);

+ buf.maxlen = 0;

+ buf.cursor = 0;

result = makeNumericAggStateCurrentContext(false);

@@ -5222,7 +5223,6 @@ numeric_avg_deserialize(PG_FUNCTION_ARGS)

result->nInfcount = pq_getmsgint64(&buf);

pq_getmsgend(&buf);

- pfree(buf.data);

free_var(&tmp_var);

@@ -5306,12 +5306,13 @@ 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.

+ * Fake up a StringInfo pointing to the bytea's value so we can "receive"

+ * the serialized aggregate state value.

- initStringInfo(&buf);

- appendBinaryStringInfo(&buf,

- VARDATA_ANY(sstate), VARSIZE_ANY_EXHDR(sstate));

+ buf.data = VARDATA_ANY(sstate);

+ buf.len = VARSIZE_ANY_EXHDR(sstate);

+ buf.maxlen = 0;

+ buf.cursor = 0;

result = makeNumericAggStateCurrentContext(false);

@@ -5342,7 +5343,6 @@ numeric_deserialize(PG_FUNCTION_ARGS)

result->nInfcount = pq_getmsgint64(&buf);

pq_getmsgend(&buf);

- pfree(buf.data);

free_var(&tmp_var);

@@ -5677,12 +5677,13 @@ 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.

+ * Fake up a StringInfo pointing to the bytea's value so we can "receive"

+ * the serialized aggregate state value.

- initStringInfo(&buf);

- appendBinaryStringInfo(&buf,

- VARDATA_ANY(sstate), VARSIZE_ANY_EXHDR(sstate));

+ buf.data = VARDATA_ANY(sstate);

+ buf.len = VARSIZE_ANY_EXHDR(sstate);

+ buf.maxlen = 0;

+ buf.cursor = 0;

result = makePolyNumAggStateCurrentContext(false);

@@ -5706,7 +5707,6 @@ numeric_poly_deserialize(PG_FUNCTION_ARGS)

#endif

pq_getmsgend(&buf);

- pfree(buf.data);

free_var(&tmp_var);

@@ -5868,12 +5868,13 @@ 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.

+ * Fake up a StringInfo pointing to the bytea's value so we can "receive"

+ * the serialized aggregate state value.

- initStringInfo(&buf);

- appendBinaryStringInfo(&buf,

- VARDATA_ANY(sstate), VARSIZE_ANY_EXHDR(sstate));

+ buf.data = VARDATA_ANY(sstate);

+ buf.len = VARSIZE_ANY_EXHDR(sstate);

+ buf.maxlen = 0;

+ buf.cursor = 0;

result = makePolyNumAggStateCurrentContext(false);

@@ -5889,7 +5890,6 @@ 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 72e1e24fe02c24217f354e931808bed941843dc0..1aff04fa77d7d3cc19c128f72639b8db3a104aec 100644 (file)

--- a/src/backend/utils/adt/varlena.c

+++ b/src/backend/utils/adt/varlena.c

@@ -5289,12 +5289,13 @@ 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.

+ * Fake up a StringInfo pointing to the bytea's value so we can "receive"

+ * the serialized aggregate state value.

- initStringInfo(&buf);

- appendBinaryStringInfo(&buf,

- VARDATA_ANY(sstate), VARSIZE_ANY_EXHDR(sstate));

+ buf.data = VARDATA_ANY(sstate);

+ buf.len = VARSIZE_ANY_EXHDR(sstate);

+ buf.maxlen = 0;

+ buf.cursor = 0;

result = makeStringAggState(fcinfo);

@@ -5307,7 +5308,6 @@ string_agg_deserialize(PG_FUNCTION_ARGS)

appendBinaryStringInfo(result, data, datalen);

pq_getmsgend(&buf);

- pfree(buf.data);

PG_RETURN_POINTER(result);

}

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