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Avoid useless buffer allocations during binary COPY FROM.

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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
This commit is contained in:
Tom Lane 2020-07-11 14:21:28 -04:00
parent ea9125304d
commit cd22d3cdb9
1 changed files with 15 additions and 5 deletions
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20
src/backend/commands/copy.c
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@ -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)