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Add explicit buffering in backend libpq, to compensate for

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buffering lost by not going through stdio anymore for client I/O.
This commit is contained in:
Tom Lane 1999-01-23 22:27:29 +00:00
parent 13c7c183f7
commit e6725d1574
5 changed files with 193 additions and 98 deletions
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6
src/backend/commands/copy.c
View File

@ -6,7 +6,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/commands/copy.c,v 1.67 1999/01/17 06:18:15 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/commands/copy.c,v 1.68 1999/01/23 22:27:26 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -303,9 +303,7 @@ DoCopy(char *relname, bool binary, bool oids, bool from, bool pipe,
}
else if (!from && !binary)
{
CopySendData("\\.\n",3,fp);
if (IsUnderPostmaster)
pq_flush();
CopySendData("\\.\n",3,fp);
}
}
}

178
src/backend/libpq/pqcomm.c
View File

@ -5,39 +5,40 @@
*
* Copyright (c) 1994, Regents of the University of California
*
* $Id: pqcomm.c,v 1.63 1999/01/17 06:18:26 momjian Exp $
* $Id: pqcomm.c,v 1.64 1999/01/23 22:27:28 tgl Exp $
*
*-------------------------------------------------------------------------
*/
/*
* INTERFACE ROUTINES
* pq_init - initialize libpq
* pq_init - initialize libpq
* pq_getport - return the PGPORT setting
* pq_close - close input / output connections
* pq_flush - flush pending output
* pq_recvbuf - load some bytes into the input buffer
* pq_getstr - get a null terminated string from connection
* pq_getchar - get 1 character from connection
* pq_peekchar - peek at first character in connection
* pq_getchar - get 1 character from connection
* pq_peekchar - peek at next character from connection
* pq_getnchar - get n characters from connection, and null-terminate
* pq_getint - get an integer from connection
* pq_putchar - send 1 character to connection
* pq_putchar - send 1 character to connection
* pq_putstr - send a null terminated string to connection
* pq_putnchar - send n characters to connection
* pq_putint - send an integer to connection
* pq_putncharlen - send n characters to connection
* pq_putncharlen - send n characters to connection
* (also send an int header indicating
* the length)
* pq_getinaddr - initialize address from host and port number
* pq_getinserv - initialize address from host and service name
*
* StreamDoUnlink - Shutdown UNIX socket connectioin
* StreamServerPort - Open sock stream
* StreamConnection - Create new connection with client
* StreamClose - Close a client/backend connection
* StreamDoUnlink - Shutdown UNIX socket connection
* StreamServerPort - Open socket stream
* StreamConnection - Create new connection with client
* StreamClose - Close a client/backend connection
*
* NOTES
* Frontend is now completey in interfaces/libpq, and no
* functions from this file is used.
* Frontend is now completely in interfaces/libpq, and no
* functions from this file are used there.
*
*/
#include "postgres.h"
@ -79,6 +80,14 @@
extern FILE * debug_port; /* in util.c */
/*
* Buffers
*/
char PqSendBuffer[PQ_BUFFER_SIZE];
char PqRecvBuffer[PQ_BUFFER_SIZE];
int PqSendPointer,PqRecvPointer,PqRecvLength;
/* --------------------------------
* pq_init - open portal file descriptors
* --------------------------------
@ -86,6 +95,7 @@ extern FILE * debug_port; /* in util.c */
void
pq_init(int fd)
{
PqSendPointer = PqRecvPointer = PqRecvLength = 0;
PQnotifies_init();
if (getenv("LIBPQ_DEBUG"))
debug_port = stderr;
@ -94,40 +104,40 @@ pq_init(int fd)
/* -------------------------
* pq_getchar()
*
* get a character from the input file,
*
* get a character from the input file, or EOF if trouble
* --------------------------------
*/
int
pq_getchar(void)
{
char c;
while (recv(MyProcPort->sock, &c, 1, 0) != 1) {
if (errno != EINTR)
return EOF; /* Not interrupted, so something went wrong */
while (PqRecvPointer >= PqRecvLength)
{
if (pq_recvbuf()) /* If nothing in buffer, then recv some */
return EOF; /* Failed to recv data */
}
return c;
return PqRecvBuffer[PqRecvPointer++];
}
/*
/* -------------------------
* pq_peekchar()
*
* get a character from the connection, but leave it in the buffer
* to be read again
* --------------------------------
* pq_peekchar - get 1 character from connection, but leave it in the stream
*/
int
pq_peekchar(void) {
char c;
while (recv(MyProcPort->sock, &c, 1, MSG_PEEK) != 1) {
if (errno != EINTR)
return EOF; /* Not interrupted, so something went wrong */
pq_peekchar(void)
{
while (PqRecvPointer >= PqRecvLength)
{
if (pq_recvbuf()) /* If nothing in buffer, then recv some */
return EOF; /* Failed to recv data */
}
return c;
/* Note we don't bump the pointer... */
return PqRecvBuffer[PqRecvPointer];
}
/* --------------------------------
* pq_getport - return the PGPORT setting
@ -150,18 +160,91 @@ pq_getport()
void
pq_close()
{
close(MyProcPort->sock);
close(MyProcPort->sock);
PQnotifies_init();
}
/* --------------------------------
* pq_flush - flush pending output
*
* returns 0 if OK, EOF if trouble
* --------------------------------
*/
void
int
pq_flush()
{
/* Not supported/required? */
char *bufptr = PqSendBuffer;
char *bufend = PqSendBuffer + PqSendPointer;
while (bufptr < bufend)
{
int r = send(MyProcPort->sock, bufptr, bufend - bufptr, 0);
if (r <= 0)
{
if (errno == EINTR)
continue; /* Ok if we were interrupted */
/* We would like to use elog() here, but cannot because elog
* tries to write to the client, which would cause a recursive
* flush attempt! So just write it out to the postmaster log.
*/
fprintf(stderr, "pq_flush: send() failed, errno %d\n", errno);
/* We drop the buffered data anyway so that processing
* can continue, even though we'll probably quit soon.
*/
PqSendPointer = 0;
return EOF;
}
bufptr += r;
}
PqSendPointer = 0;
return 0;
}
/* --------------------------------
* pq_recvbuf - load some bytes into the input buffer
*
* returns 0 if OK, EOF if trouble
* --------------------------------
*/
int
pq_recvbuf()
{
if (PqRecvPointer > 0)
{
if (PqRecvLength > PqRecvPointer)
{
/* still some unread data, left-justify it in the buffer */
memmove(PqRecvBuffer, PqRecvBuffer+PqRecvPointer,
PqRecvLength-PqRecvPointer);
PqRecvLength -= PqRecvPointer;
PqRecvPointer = 0;
}
else
PqRecvLength = PqRecvPointer = 0;
}
/* Can fill buffer from PqRecvLength and upwards */
for (;;)
{
int r = recv(MyProcPort->sock, PqRecvBuffer + PqRecvLength,
PQ_BUFFER_SIZE - PqRecvLength, 0);
if (r <= 0)
{
if (errno == EINTR)
continue; /* Ok if interrupted */
/* We would like to use elog() here, but dare not because elog
* tries to write to the client, which will cause problems
* if we have a hard communications failure ...
* So just write the message to the postmaster log.
*/
fprintf(stderr, "pq_recvbuf: recv() failed, errno %d\n", errno);
return EOF;
}
/* r contains number of bytes read, so just incr length */
PqRecvLength += r;
return 0;
}
}
/* --------------------------------
@ -194,7 +277,7 @@ pq_getstr(char *s, int maxlen)
int
pq_getnchar(char *s, int off, int maxlen)
{
int r = pqGetNBytes(s + off, maxlen);
int r = pqGetNBytes(s + off, maxlen);
s[off+maxlen] = '\0';
return r;
}
@ -602,7 +685,7 @@ StreamConnection(int server_fd, Port *port)
if (setsockopt(port->sock, pe->p_proto, TCP_NODELAY,
&on, sizeof(on)) < 0)
{
elog(ERROR, "postmaster: setsockopt failed");
elog(ERROR, "postmaster: setsockopt failed: %m");
return STATUS_ERROR;
}
}
@ -644,18 +727,9 @@ pq_putncharlen(char *s, int n)
*/
int pq_putchar(char c)
{
char isDone = 0;
do {
if (send(MyProcPort->sock, &c, 1, 0) != 1) {
if (errno != EINTR)
return EOF; /* Anything other than interrupt is error! */
}
else
isDone = 1; /* Done if we sent one char */
} while (!isDone);
return c;
if (PqSendPointer >= PQ_BUFFER_SIZE)
if (pq_flush()) /* If buffer is full, then flush it out */
return EOF;
PqSendBuffer[PqSendPointer++] = c; /* Put in buffer */
return c;
}

73
src/backend/libpq/pqcomprim.c
View File

@ -98,7 +98,7 @@ pqPutLong(int integer)
n = ((PG_PROTOCOL_MAJOR(FrontendProtocol) == 0) ? hton_l(integer) : htonl((uint32) integer));
#endif
return pqPutNBytes((char *)&n,4);
return pqPutNBytes((char *)&n, 4);
}
/* --------------------------------------------------------------------- */
@ -107,7 +107,7 @@ pqGetShort(int *result)
{
uint16 n;
if (pqGetNBytes((char *)&n,2) != 0)
if (pqGetNBytes((char *)&n, 2) != 0)
return EOF;
#ifdef FRONTEND
@ -138,28 +138,29 @@ pqGetLong(int *result)
}
/* --------------------------------------------------------------------- */
/* pqGetNBytes: Read a chunk of exactly len bytes in buffer s (which must be 1
byte longer) and terminate it with a '\0'.
Return 0 if ok.
*/
/* pqGetNBytes: Read a chunk of exactly len bytes into buffer s.
* Return 0 if ok, EOF if trouble.
*/
int
pqGetNBytes(char *s, size_t len)
{
int bytesDone = 0;
size_t amount;
do {
int r = recv(MyProcPort->sock, s+bytesDone, len-bytesDone, 0);
if (r == 0 || r == -1) {
if (errno != EINTR)
return EOF; /* All other than signal-interrupted is error */
continue; /* Otherwise, try again */
}
/* r contains number of bytes received */
bytesDone += r;
} while (bytesDone < len);
/* Zero-termination now in pq_getnchar() instead */
while (len > 0)
{
while (PqRecvPointer >= PqRecvLength)
{
if (pq_recvbuf()) /* If nothing in buffer, then recv some */
return EOF; /* Failed to recv data */
}
amount = PqRecvLength - PqRecvPointer;
if (amount > len)
amount = len;
memcpy(s, PqRecvBuffer + PqRecvPointer, amount);
PqRecvPointer += amount;
s += amount;
len -= amount;
}
return 0;
}
@ -167,20 +168,21 @@ pqGetNBytes(char *s, size_t len)
int
pqPutNBytes(const char *s, size_t len)
{
int bytesDone = 0;
do {
int r = send(MyProcPort->sock, s+bytesDone, len-bytesDone, 0);
if (r == 0 || r == -1) {
if (errno != EINTR)
return EOF; /* Only signal interruption allowed */
continue; /* If interruped and read nothing, just try again */
}
/* r contains number of bytes sent so far */
bytesDone += r;
} while (bytesDone < len);
size_t amount;
while (len > 0)
{
if (PqSendPointer >= PQ_BUFFER_SIZE)
if (pq_flush()) /* If buffer is full, then flush it out */
return EOF;
amount = PQ_BUFFER_SIZE - PqSendPointer;
if (amount > len)
amount = len;
memcpy(PqSendBuffer + PqSendPointer, s, amount);
PqSendPointer += amount;
s += amount;
len -= amount;
}
return 0;
}
@ -191,8 +193,8 @@ pqGetString(char *s, size_t len)
int c;
/*
* Keep on reading until we get the terminating '\0' and discard those
* bytes we don't have room for.
* Keep on reading until we get the terminating '\0',
* discarding any bytes we don't have room for.
*/
while ((c = pq_getchar()) != EOF && c != '\0')
@ -216,4 +218,3 @@ pqPutString(const char *s)
{
return pqPutNBytes(s,strlen(s)+1);
}

11
src/backend/utils/error/elog.c
View File

@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/utils/error/elog.c,v 1.37 1999/01/11 03:56:07 scrappy Exp $
* $Header: /cvsroot/pgsql/src/backend/utils/error/elog.c,v 1.38 1999/01/23 22:27:29 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -192,8 +192,15 @@ elog(int lev, const char *fmt,...)
pq_putnchar("N", 1);
else
pq_putnchar("E", 1);
/* pq_putint(-101, 4); *//* should be query id */
pq_putstr(line + TIMESTAMP_SIZE); /* don't show timestamps */
/*
* This flush is normally not necessary, since postgres.c will
* flush out waiting data when control returns to the main loop.
* But it seems best to leave it here, so that the client has some
* clue what happened if the backend dies before getting back to the
* main loop ... error/notice messages should not be a performance-
* critical path anyway, so an extra flush won't hurt much ...
*/
pq_flush();
}
if (!IsUnderPostmaster)

23
src/include/libpq/libpq.h
View File

@ -6,7 +6,7 @@
*
* Copyright (c) 1994, Regents of the University of California
*
* $Id: libpq.h,v 1.23 1999/01/12 12:49:52 scrappy Exp $
* $Id: libpq.h,v 1.24 1999/01/23 22:27:25 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -254,12 +254,13 @@ extern void pq_init(int fd);
extern void pq_gettty(char *tp);
extern int pq_getport(void);
extern void pq_close(void);
extern void pq_flush(void);
extern int pq_flush(void);
extern int pq_recvbuf(void);
extern int pq_getstr(char *s, int maxlen);
extern int PQgetline(char *s, int maxlen);
extern int PQputline(char *s);
extern int pq_getchar(void);
extern int pq_peekchar(void);
extern int pq_getchar(void);
extern int pq_peekchar(void);
extern int pq_getnchar(char *s, int off, int maxlen);
extern int pq_getint(int b);
extern int pq_putchar(char c);
@ -282,4 +283,18 @@ extern int StreamServerPort(char *hostName, short portName, int *fdP);
extern int StreamConnection(int server_fd, Port *port);
extern void StreamClose(int sock);
/*
* Internal send/receive buffers in libpq.
* These probably shouldn't be global at all, but unless we merge
* pqcomm.c and pqcomprim.c they have to be...
*/
#define PQ_BUFFER_SIZE 8192
extern char PqSendBuffer[PQ_BUFFER_SIZE];
extern int PqSendPointer; /* Next index to store a byte in PqSendBuffer */
extern char PqRecvBuffer[PQ_BUFFER_SIZE];
extern int PqRecvPointer; /* Next index to read a byte from PqRecvBuffer */
extern int PqRecvLength; /* End of data available in PqRecvBuffer */
#endif /* LIBPQ_H */