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[PATCH 1/1] In psql \copy from, send data to server in larger chunks.
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* [PATCH 1/1] In psql \copy from, send data to server in larger chunks.
@ 2021-02-06 22:10  Heikki Linnakangas <[email protected]>
  0 siblings, 0 replies; 2+ messages in thread

From: Heikki Linnakangas @ 2021-02-06 22:10 UTC (permalink / raw)

Previously, we would send each line as a separate CopyData message.
That's pretty wasteful if the table is narrow, as each CopyData message
has 5 bytes of overhead. For efficiency, buffer up and pack 8 kB of input
data into each CopyData message.
---
 src/bin/psql/copy.c | 114 +++++++++++++++++++++++++++-----------------
 1 file changed, 69 insertions(+), 45 deletions(-)

diff --git a/src/bin/psql/copy.c b/src/bin/psql/copy.c
index 78f0dc5a507..8c56f2470e2 100644
--- a/src/bin/psql/copy.c
+++ b/src/bin/psql/copy.c
@@ -581,77 +581,101 @@ handleCopyIn(PGconn *conn, FILE *copystream, bool isbinary, PGresult **res)
 	else
 	{
 		bool		copydone = false;
+		int			buflen;
+		bool		at_line_begin = true;
 
+		if (showprompt)
+		{
+			const char *prompt = get_prompt(PROMPT_COPY, NULL);
+
+			fputs(prompt, stdout);
+			fflush(stdout);
+		}
+
+		/*
+		 * In text mode, We have to read the input one line at a time, so that
+		 * we can stop reading at the EOF marker (\.).  We mustn't read beyond
+		 * the EOF marker, because if the data is inlined in a SQL script, we
+		 * would eat up the commands after the EOF marker.
+		 */
+		buflen = 0;
 		while (!copydone)
-		{						/* for each input line ... */
-			bool		firstload;
-			bool		linedone;
+		{
+			int			linelen;
+			char	   *fgresult;
 
-			if (showprompt)
+			if (at_line_begin && showprompt)
 			{
-				const char *prompt = get_prompt(PROMPT_COPY, NULL);
+				const char *prompt;
 
+				sigint_interrupt_enabled = false;
+
+				prompt = get_prompt(PROMPT_COPY, NULL);
 				fputs(prompt, stdout);
 				fflush(stdout);
-			}
 
-			firstload = true;
-			linedone = false;
-
-			while (!linedone)
-			{					/* for each bufferload in line ... */
-				int			linelen;
-				char	   *fgresult;
-
-				/* enable longjmp while waiting for input */
 				sigint_interrupt_enabled = true;
+			}
 
-				fgresult = fgets(buf, sizeof(buf), copystream);
-
-				sigint_interrupt_enabled = false;
+			/* enable longjmp while waiting for input */
+			sigint_interrupt_enabled = true;
 
-				if (!fgresult)
-				{
-					copydone = true;
-					break;
-				}
+			fgresult = fgets(&buf[buflen], COPYBUFSIZ - buflen, copystream);
 
-				linelen = strlen(buf);
+			sigint_interrupt_enabled = false;
 
-				/* current line is done? */
-				if (linelen > 0 && buf[linelen - 1] == '\n')
-					linedone = true;
+			if (!fgresult)
+				copydone = true;
+			else
+			{
+				linelen = strlen(fgresult);
+				buflen += linelen;
 
-				/* check for EOF marker, but not on a partial line */
-				if (firstload)
+				if (buf[buflen - 1] == '\n')
 				{
-					/*
-					 * This code erroneously assumes '\.' on a line alone
-					 * inside a quoted CSV string terminates the \copy.
-					 * https://www.postgresql.org/message-id/[email protected]
-					 */
-					if (strcmp(buf, "\\.\n") == 0 ||
-						strcmp(buf, "\\.\r\n") == 0)
+					/* check for EOF marker, but not on a partial line */
+					if (at_line_begin)
 					{
-						copydone = true;
-						break;
+						/*
+						 * This code erroneously assumes '\.' on a line alone
+						 * inside a quoted CSV string terminates the \copy.
+						 * https://www.postgresql.org/message-id/[email protected]
+						 */
+						if ((linelen == 3 && memcmp(fgresult, "\\.\n", 3) == 0) ||
+							(linelen == 4 && memcmp(fgresult, "\\.\r\n", 4) == 0))
+						{
+							copydone = true;
+						}
 					}
 
-					firstload = false;
+					if (copystream == pset.cur_cmd_source)
+					{
+						pset.lineno++;
+						pset.stmt_lineno++;
+					}
+					at_line_begin = true;
 				}
+				else
+					at_line_begin = false;
+			}
 
-				if (PQputCopyData(conn, buf, linelen) <= 0)
+			/*
+			 * If the buffer is full, or we've reached the EOF, flush it.
+			 *
+			 * Make sure there's always space for four more bytes in the buffer,
+			 * plus a NUL terminator. That way, an EOF marker is never split
+			 * across two fgets() calls, which simplies the logic.
+			 */
+			if (buflen >= COPYBUFSIZ - 5 || (copydone && buflen > 0))
+			{
+				if (PQputCopyData(conn, buf, buflen) <= 0)
 				{
 					OK = false;
 					copydone = true;
 					break;
 				}
-			}
 
-			if (copystream == pset.cur_cmd_source)
-			{
-				pset.lineno++;
-				pset.stmt_lineno++;
+				buflen = 0;
 			}
 		}
 	}
-- 
2.30.0


--------------20DC7BBD34247104D0B00618--





^ permalink  raw  reply  [nested|flat] 2+ messages in thread

* Re: test_escape: invalid option -- 'c'
@ 2025-02-19 00:53  Michael Paquier <[email protected]>
  0 siblings, 0 replies; 2+ messages in thread

From: Michael Paquier @ 2025-02-19 00:53 UTC (permalink / raw)
  To: Japin Li <[email protected]>; +Cc: pgsql-hackers

On Tue, Feb 18, 2025 at 12:46:50PM +0900, Michael Paquier wrote:
> You are right, obviously.  The only reason why this is not showing up
> is that the TAP test uses the long option --conninfo.  Speaking of
> which, this had better use fat commas to combine the option/value
> pairs in these commands.

This was also missing 'f', which is listed as an option.  I've
reordered all these to be alphabetical in the list, and applied the
result down to v13.  Thanks for the report.
--
Michael


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2021-02-06 22:10 [PATCH 1/1] In psql \copy from, send data to server in larger chunks. Heikki Linnakangas <[email protected]>
2025-02-19 00:53 Re: test_escape: invalid option -- 'c' Michael Paquier <[email protected]>

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