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Commit4d63e26

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Further hacking on performance of COPY OUT. It seems that fwrite()'s
per-call overhead is quite significant, at least on Linux: whateverit's doing is more than just shoving the bytes into a buffer. Bufferingthe data so we can call fwrite() just once per row seems to be a win.
1 parent223ae69 commit4d63e26

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1 file changed

+40
-45
lines changed

1 file changed

+40
-45
lines changed

‎src/backend/commands/copy.c‎

Lines changed: 40 additions & 45 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $PostgreSQL: pgsql/src/backend/commands/copy.c,v 1.265 2006/05/25 18:42:17 tgl Exp $
11+
* $PostgreSQL: pgsql/src/backend/commands/copy.c,v 1.266 2006/05/26 22:50:02 tgl Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -95,7 +95,8 @@ typedef struct CopyStateData
9595
/* low-level state data */
9696
CopyDestcopy_dest;/* type of copy source/destination */
9797
FILE*copy_file;/* used if copy_dest == COPY_FILE */
98-
StringInfofe_msgbuf;/* used if copy_dest == COPY_NEW_FE */
98+
StringInfofe_msgbuf;/* used for all dests during COPY TO, only
99+
* for dest == COPY_NEW_FE in COPY FROM */
99100
boolfe_copy;/* true for all FE copy dests */
100101
boolfe_eof;/* true if detected end of copy data */
101102
EolTypeeol_type;/* EOL type of input */
@@ -287,7 +288,6 @@ SendCopyBegin(CopyState cstate)
287288
pq_sendint(&buf,format,2);/* per-column formats */
288289
pq_endmessage(&buf);
289290
cstate->copy_dest=COPY_NEW_FE;
290-
cstate->fe_msgbuf=makeStringInfo();
291291
}
292292
elseif (PG_PROTOCOL_MAJOR(FrontendProtocol) >=2)
293293
{
@@ -364,23 +364,16 @@ SendCopyEnd(CopyState cstate)
364364
{
365365
if (cstate->copy_dest==COPY_NEW_FE)
366366
{
367-
if (cstate->binary)
368-
{
369-
/* Need to flush out file trailer word */
370-
CopySendEndOfRow(cstate);
371-
}
372-
else
373-
{
374-
/* Shouldn't have any unsent data */
375-
Assert(cstate->fe_msgbuf->len==0);
376-
}
367+
/* Shouldn't have any unsent data */
368+
Assert(cstate->fe_msgbuf->len==0);
377369
/* Send Copy Done message */
378370
pq_putemptymessage('c');
379371
}
380372
else
381373
{
382-
/* The FE/BE protocol uses \n as newline for all platforms */
383-
CopySendData(cstate,"\\.\n",3);
374+
CopySendData(cstate,"\\.",2);
375+
/* Need to flush out the trailer (this also appends a newline) */
376+
CopySendEndOfRow(cstate);
384377
pq_endcopyout(false);
385378
}
386379
}
@@ -390,53 +383,34 @@ SendCopyEnd(CopyState cstate)
390383
* CopySendString does the same for null-terminated strings
391384
* CopySendChar does the same for single characters
392385
* CopySendEndOfRow does the appropriate thing at end of each data row
386+
*(data is not actually flushed except by CopySendEndOfRow)
393387
*
394388
* NB: no data conversion is applied by these functions
395389
*----------
396390
*/
397391
staticvoid
398392
CopySendData(CopyStatecstate,void*databuf,intdatasize)
399393
{
400-
switch (cstate->copy_dest)
401-
{
402-
caseCOPY_FILE:
403-
fwrite(databuf,datasize,1,cstate->copy_file);
404-
if (ferror(cstate->copy_file))
405-
ereport(ERROR,
406-
(errcode_for_file_access(),
407-
errmsg("could not write to COPY file: %m")));
408-
break;
409-
caseCOPY_OLD_FE:
410-
if (pq_putbytes((char*)databuf,datasize))
411-
{
412-
/* no hope of recovering connection sync, so FATAL */
413-
ereport(FATAL,
414-
(errcode(ERRCODE_CONNECTION_FAILURE),
415-
errmsg("connection lost during COPY to stdout")));
416-
}
417-
break;
418-
caseCOPY_NEW_FE:
419-
appendBinaryStringInfo(cstate->fe_msgbuf,
420-
(char*)databuf,datasize);
421-
break;
422-
}
394+
appendBinaryStringInfo(cstate->fe_msgbuf, (char*)databuf,datasize);
423395
}
424396

425397
staticvoid
426398
CopySendString(CopyStatecstate,constchar*str)
427399
{
428-
CopySendData(cstate, (void*)str,strlen(str));
400+
appendBinaryStringInfo(cstate->fe_msgbuf,str,strlen(str));
429401
}
430402

431403
staticvoid
432404
CopySendChar(CopyStatecstate,charc)
433405
{
434-
CopySendData(cstate,&c,1);
406+
appendStringInfoCharMacro(cstate->fe_msgbuf,c);
435407
}
436408

437409
staticvoid
438410
CopySendEndOfRow(CopyStatecstate)
439411
{
412+
StringInfofe_msgbuf=cstate->fe_msgbuf;
413+
440414
switch (cstate->copy_dest)
441415
{
442416
caseCOPY_FILE:
@@ -449,24 +423,40 @@ CopySendEndOfRow(CopyState cstate)
449423
CopySendString(cstate,"\r\n");
450424
#endif
451425
}
426+
427+
(void)fwrite(fe_msgbuf->data,fe_msgbuf->len,
428+
1,cstate->copy_file);
429+
if (ferror(cstate->copy_file))
430+
ereport(ERROR,
431+
(errcode_for_file_access(),
432+
errmsg("could not write to COPY file: %m")));
452433
break;
453434
caseCOPY_OLD_FE:
454435
/* The FE/BE protocol uses \n as newline for all platforms */
455436
if (!cstate->binary)
456437
CopySendChar(cstate,'\n');
438+
439+
if (pq_putbytes(fe_msgbuf->data,fe_msgbuf->len))
440+
{
441+
/* no hope of recovering connection sync, so FATAL */
442+
ereport(FATAL,
443+
(errcode(ERRCODE_CONNECTION_FAILURE),
444+
errmsg("connection lost during COPY to stdout")));
445+
}
457446
break;
458447
caseCOPY_NEW_FE:
459448
/* The FE/BE protocol uses \n as newline for all platforms */
460449
if (!cstate->binary)
461450
CopySendChar(cstate,'\n');
451+
462452
/* Dump the accumulated row as one CopyData message */
463-
(void)pq_putmessage('d',cstate->fe_msgbuf->data,
464-
cstate->fe_msgbuf->len);
465-
/* Reset fe_msgbuf to empty */
466-
cstate->fe_msgbuf->len=0;
467-
cstate->fe_msgbuf->data[0]='\0';
453+
(void)pq_putmessage('d',fe_msgbuf->data,fe_msgbuf->len);
468454
break;
469455
}
456+
457+
/* Reset fe_msgbuf to empty */
458+
fe_msgbuf->len=0;
459+
fe_msgbuf->data[0]='\0';
470460
}
471461

472462
/*
@@ -1237,6 +1227,9 @@ CopyTo(CopyState cstate)
12371227
attr_count=list_length(cstate->attnumlist);
12381228
null_print_client=cstate->null_print;/* default */
12391229

1230+
/* We use fe_msgbuf as a per-row buffer regardless of copy_dest */
1231+
cstate->fe_msgbuf=makeStringInfo();
1232+
12401233
/* Get info about the columns we need to process. */
12411234
out_functions= (FmgrInfo*)palloc(num_phys_attrs*sizeof(FmgrInfo));
12421235
force_quote= (bool*)palloc(num_phys_attrs*sizeof(bool));
@@ -1423,6 +1416,8 @@ CopyTo(CopyState cstate)
14231416
{
14241417
/* Generate trailer for a binary copy */
14251418
CopySendInt16(cstate,-1);
1419+
/* Need to flush out the trailer */
1420+
CopySendEndOfRow(cstate);
14261421
}
14271422

14281423
MemoryContextDelete(mycontext);

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