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Avoid useless buffer allocations during binary COPY FROM.

2020年7月11日 18:21:28 +0000 (14:21 -0400)

The raw_buf and line_buf buffers aren't used when reading binary format,
so skip allocating them. raw_buf is 64K so that seems like a worthwhile
savings. An unused line_buf only wastes 1K, but as long as we're checking
it's free to avoid allocating that too.

Bharath Rupireddy, tweaked a bit by me

Discussion: https://postgr.es/m/CALj2ACXcCKaGPY0whowqrJ4OPJvDnTssgpGCzvuFQu5z0CXb-g@mail.gmail.com

src/backend/commands/copy.c patch | blob | blame | history

diff --git a/src/backend/commands/copy.c b/src/backend/commands/copy.c

index 3e199bdfd0c6520a455f821df8acfedc0df76ede..99d14571801224ba8cfe4bf87829ae0ec8db2e65 100644 (file)

--- a/src/backend/commands/copy.c

+++ b/src/backend/commands/copy.c

@@ -193,6 +193,9 @@ typedef struct CopyStateData

* the current line. The CopyReadAttributes functions return arrays of

* pointers into this buffer. We avoid palloc/pfree overhead by re-using

* the buffer on each cycle.

+ *

+ * (In binary COPY FROM, attribute_buf holds the binary data for the

+ * current field, while the other variables are not used.)

StringInfoData attribute_buf;

@@ -3359,12 +3362,19 @@ BeginCopyFrom(ParseState *pstate,

cstate->cur_attname = NULL;

cstate->cur_attval = NULL;

- /* Set up variables to avoid per-attribute overhead. */

+ /*

+ * Set up variables to avoid per-attribute overhead. attribute_buf is

+ * used in both text and binary modes, but we use line_buf and raw_buf

+ * only in text mode.

+ */

initStringInfo(&cstate->attribute_buf);

- initStringInfo(&cstate->line_buf);

- cstate->line_buf_converted = false;

- cstate->raw_buf = (char *) palloc(RAW_BUF_SIZE + 1);

- cstate->raw_buf_index = cstate->raw_buf_len = 0;

+ if (!cstate->binary)

+ {

+ initStringInfo(&cstate->line_buf);

+ cstate->line_buf_converted = false;

+ cstate->raw_buf = (char *) palloc(RAW_BUF_SIZE + 1);

+ cstate->raw_buf_index = cstate->raw_buf_len = 0;

+ }

/* Assign range table, we'll need it in CopyFrom. */

if (pstate)

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