LIBPQ patches ... - Mailing list pgsql-hackers

Does anyone have anything against me applying this to the current source
tree?  


Marc G. Fournier                   ICQ#7615664               IRC Nick: Scrappy
Systems Administrator @ hub.org 
primary: scrappy@hub.org           secondary: scrappy@{freebsd|postgresql}.org 

---------- Forwarded message ----------
Date: Fri, 17 Dec 1999 13:51:50 -0800 (PST)
From: Alfred Perlstein <bright@wintelcom.net>
To: The Hermit Hacker <scrappy@hub.org>
Subject: Re: pctrackd updates and such

On Fri, 17 Dec 1999, The Hermit Hacker wrote:

> 
> Okay, first thing...can you redo these as context diffs?  We generally
> refuse *any* patches that aren't context...

sure.

> 
> Second, are these against a reasonably current snapshot of PostgreSQL
> (aka. the upcoming v7), or v6.5.3 release?  If v6.5.3, we're gonna need to
> get these v7.x ready before we can commit them...

they are against a checked out cvs copy as of a couple days ago,
and should apply cleanly to what's in the current repo.

> Once both of the above conditions are in place, and after I get back from
> BC, I'll work on  getting these into the v7.0 release...or, at least,
> talked/commented about if there are any objections...
> 
> I'm outta here for 10 days...Happy Holidays and talk with ya when I get
> back...

ok, cool see you soon. :)

-Alfred

don't forget the problem with sending queries that may occur:

i'm not sure if handlesendfailure() can cope with only sending
a 'Q' to the backend, we may have to work out reservations or
something for space, another idea would be to implement a 
pqWritev() of some sort that would take an array of pointers
and lengths to send to the backend and only allow any data to
go into the backend if the entire string can fit.

then again, handlesendfailure may work, but doing reservations
for the send buffer seems cleaner...

diff's contexted against pgsql-'current':


Index: fe-connect.c
===================================================================
RCS file: /home/pgcvs/pgsql/src/interfaces/libpq/fe-connect.c,v
retrieving revision 1.108
diff -u -c -r1.108 fe-connect.c
cvs diff: conflicting specifications of output style
*** fe-connect.c    1999/12/02 00:26:15    1.108
--- fe-connect.c    1999/12/14 09:42:24
***************
*** 595,625 ****     return 0; } 
- 
- /* ----------
-  * connectMakeNonblocking -
-  * Make a connection non-blocking.
-  * Returns 1 if successful, 0 if not.
-  * ----------
-  */
- static int
- connectMakeNonblocking(PGconn *conn)
- {
- #ifndef WIN32
-     if (fcntl(conn->sock, F_SETFL, O_NONBLOCK) < 0)
- #else
-     if (ioctlsocket(conn->sock, FIONBIO, &on) != 0)
- #endif
-     {
-         printfPQExpBuffer(&conn->errorMessage,
-                           "connectMakeNonblocking -- fcntl() failed: errno=%d\n%s\n",
-                           errno, strerror(errno));
-         return 0;
-     }
- 
-     return 1;
- }
-  /* ----------  * connectNoDelay -  * Sets the TCP_NODELAY socket option.
--- 595,600 ----
***************
*** 792,798 ****      *   Ewan Mellor <eem21@cam.ac.uk>.      * ---------- */ #if (!defined(WIN32) ||
defined(WIN32_NON_BLOCKING_CONNECTIONS))&& !defined(USE_SSL)
 
!     if (!connectMakeNonblocking(conn))         goto connect_errReturn; #endif     
--- 767,773 ----      *   Ewan Mellor <eem21@cam.ac.uk>.      * ---------- */ #if (!defined(WIN32) ||
defined(WIN32_NON_BLOCKING_CONNECTIONS))&& !defined(USE_SSL)
 
!     if (PQsetnonblocking(conn, TRUE) != 0)         goto connect_errReturn; #endif     
***************
*** 904,910 ****     /* This makes the connection non-blocking, for all those cases which forced us        not to do it
above.*/ #if (defined(WIN32) && !defined(WIN32_NON_BLOCKING_CONNECTIONS)) || defined(USE_SSL)
 
!     if (!connectMakeNonblocking(conn))         goto connect_errReturn; #endif     
--- 879,885 ----     /* This makes the connection non-blocking, for all those cases which forced us        not to do it
above.*/ #if (defined(WIN32) && !defined(WIN32_NON_BLOCKING_CONNECTIONS)) || defined(USE_SSL)
 
!     if (PQsetnonblocking(conn, TRUE) != 0)         goto connect_errReturn; #endif     
***************
*** 1702,1707 ****
--- 1677,1683 ----     conn->inBuffer = (char *) malloc(conn->inBufSize);     conn->outBufSize = 8 * 1024;
conn->outBuffer= (char *) malloc(conn->outBufSize);
 
+     conn->nonblocking = FALSE;     initPQExpBuffer(&conn->errorMessage);     initPQExpBuffer(&conn->workBuffer);
if(conn->inBuffer == NULL ||
 
***************
*** 1811,1816 ****
--- 1787,1793 ----     conn->lobjfuncs = NULL;     conn->inStart = conn->inCursor = conn->inEnd = 0;     conn->outCount
=0;
 
+     conn->nonblocking = FALSE;  } 
Index: fe-exec.c
===================================================================
RCS file: /home/pgcvs/pgsql/src/interfaces/libpq/fe-exec.c,v
retrieving revision 1.86
diff -u -c -r1.86 fe-exec.c
cvs diff: conflicting specifications of output style
*** fe-exec.c    1999/11/11 00:10:14    1.86
--- fe-exec.c    1999/12/14 05:55:11
***************
*** 13,18 ****
--- 13,19 ----  */ #include <errno.h> #include <ctype.h>
+ #include <fcntl.h>  #include "postgres.h" #include "libpq-fe.h"
***************
*** 24,30 **** #include <unistd.h> #endif 
-  /* keep this in same order as ExecStatusType in libpq-fe.h */ const char *const pgresStatus[] = {
"PGRES_EMPTY_QUERY",
--- 25,30 ----
***************
*** 574,580 ****
--- 574,588 ----      * we will NOT block waiting for more input.      */     if (pqReadData(conn) < 0)
+     {
+         /*
+          * try to flush the send-queue otherwise we may never get a 
+          * resonce for something that may not have already been sent
+          * because it's in our write buffer!
+          */
+         pqFlush(conn);         return 0;
+     }     /* Parsing of the data waits till later. */     return 1; }
***************
*** 1088,1095 ****
--- 1096,1112 ---- {     PGresult   *result;     PGresult   *lastResult;
+     bool    savedblocking;      /*
+      * we assume anyone calling PQexec wants blocking behaviour,
+      * we force the blocking status of the connection to blocking
+      * for the duration of this function and restore it on return
+      */
+     savedblocking = PQisnonblocking(conn);
+     PQsetnonblocking(conn, FALSE);
+ 
+     /*      * Silently discard any prior query result that application didn't      * eat. This is probably poor
design,but it's here for backward      * compatibility.
 
***************
*** 1102,1115 ****             PQclear(result);             printfPQExpBuffer(&conn->errorMessage,
"PQexec:you gotta get out of a COPY state yourself.\n");
 
!             return NULL;         }         PQclear(result);     }      /* OK to send the message */     if
(!PQsendQuery(conn,query))
 
!         return NULL;      /*      * For backwards compatibility, return the last result if there are
--- 1119,1133 ----             PQclear(result);             printfPQExpBuffer(&conn->errorMessage,
"PQexec:you gotta get out of a COPY state yourself.\n");
 
!             /* restore blocking status */
!             goto errout;         }         PQclear(result);     }      /* OK to send the message */     if
(!PQsendQuery(conn,query))
 
!         goto errout;      /*      * For backwards compatibility, return the last result if there are
***************
*** 1142,1148 ****
--- 1160,1172 ----             result->resultStatus == PGRES_COPY_OUT)             break;     }
+ 
+     PQsetnonblocking(conn, savedblocking);     return lastResult;
+ 
+ errout:
+     PQsetnonblocking(conn, savedblocking);
+     return NULL; }  
***************
*** 1431,1438 ****              "PQendcopy() -- I don't think there's a copy in progress.\n");         return 1;     }

!     (void) pqFlush(conn);        /* make sure no data is waiting to be sent */      /* Return to active duty */
conn->asyncStatus= PGASYNC_BUSY;
 
--- 1455,1468 ----              "PQendcopy() -- I don't think there's a copy in progress.\n");         return 1;     }
+ 
+     /* make sure no data is waiting to be sent */
+     if (pqFlush(conn))
+         return (1); 
!     /* non blocking connections may have to abort at this point. */
!     if (PQisnonblocking(conn) && PQisBusy(conn))
!         return (1);      /* Return to active duty */     conn->asyncStatus = PGASYNC_BUSY;
***************
*** 2025,2028 ****
--- 2055,2126 ----         return 1;     else         return 0;
+ }
+ 
+ /* PQsetnonblocking:
+      sets the PGconn's database connection non-blocking if the arg is TRUE
+      or makes it non-blocking if the arg is FALSE, this will not protect
+      you from PQexec(), you'll only be safe when using the non-blocking
+      API
+      Needs to be called only on a connected database connection.
+ */
+ 
+ int
+ PQsetnonblocking(PGconn *conn, int arg)
+ {
+     int    fcntlarg;
+ 
+     arg = (arg == TRUE) ? 1 : 0;
+     if (arg == conn->nonblocking)
+         return (0);
+ 
+ #ifdef USE_SSL
+     if (conn->ssl)
+     {
+         printfPQExpBuffer(&conn->errorMessage,
+             "PQsetnonblocking() -- not supported when using SSL\n");
+         return (-1);
+     }
+ #endif /* USE_SSL */
+ 
+ #ifndef WIN32
+     fcntlarg = fcntl(conn->sock, F_GETFL, 0);
+     if (fcntlarg == -1)
+         return (-1);
+ 
+     if ((arg == TRUE && 
+         fcntl(conn->sock, F_SETFL, fcntlarg | O_NONBLOCK) == -1) ||
+         (arg == FALSE &&
+         fcntl(conn->sock, F_SETFL, fcntlarg & ~O_NONBLOCK) == -1)) 
+ #else
+     fcntlarg = arg;
+     if (ioctlsocket(conn->sock, FIONBIO, &fcntlarg) != 0)
+ #endif
+     {
+         printfPQExpBuffer(&conn->errorMessage,
+             "PQsetblocking() -- unable to set nonblocking status to %s\n",
+             arg == TRUE ? "TRUE" : "FALSE");
+         return (-1);
+     }
+ 
+     conn->nonblocking = arg;
+     return (0);
+ }
+ 
+ /* return the blocking status of the database connection, TRUE == nonblocking,
+      FALSE == blocking
+ */
+ int
+ PQisnonblocking(PGconn *conn)
+ {
+ 
+     return (conn->nonblocking);
+ }
+ 
+ /* try to force data out, really only useful for non-blocking users */
+ int
+ PQflush(PGconn *conn)
+ {
+ 
+     return (pqFlush(conn)); }
Index: fe-misc.c
===================================================================
RCS file: /home/pgcvs/pgsql/src/interfaces/libpq/fe-misc.c,v
retrieving revision 1.33
diff -u -c -r1.33 fe-misc.c
cvs diff: conflicting specifications of output style
*** fe-misc.c    1999/11/30 03:08:19    1.33
--- fe-misc.c    1999/12/14 08:21:09
***************
*** 86,91 ****
--- 86,119 ---- {     size_t avail = Max(conn->outBufSize - conn->outCount, 0); 
+     /*
+      * if we are non-blocking and the send queue is too full to buffer this
+      * request then try to flush some and return an error 
+      */
+     if (PQisnonblocking(conn) && nbytes > avail && pqFlush(conn))
+     {
+         /* 
+          * even if the flush failed we may still have written some
+          * data, recalculate the size of the send-queue relative
+          * to the amount we have to send, we may be able to queue it
+          * afterall even though it's not sent to the database it's
+          * ok, any routines that check the data coming from the
+          * database better call pqFlush() anyway.
+          */
+         if (nbytes > Max(conn->outBufSize - conn->outCount, 0))
+         {
+             printfPQExpBuffer(&conn->errorMessage,
+                 "pqPutBytes --  pqFlush couldn't flush enough"
+                 " data: space available: %d, space needed %d\n",
+                 Max(conn->outBufSize - conn->outCount, 0), nbytes);
+             return EOF;
+         }
+     }
+ 
+     /* 
+      * the non-blocking code above makes sure that this isn't true,
+      * essentially this is no-op
+      */     while (nbytes > avail)     {         memcpy(conn->outBuffer + conn->outCount, s, avail);
***************
*** 548,553 ****
--- 576,589 ----         return EOF;     } 
+     /* 
+      * don't try to send zero data, allows us to use this function
+      * without too much worry about overhead
+      */
+     if (len == 0)
+         return (0);
+ 
+     /* while there's still data to send */     while (len > 0)     {         /* Prevent being SIGPIPEd if backend has
closedthe connection. */
 
***************
*** 556,561 ****
--- 592,598 ---- #endif          int sent;
+  #ifdef USE_SSL         if (conn->ssl)            sent = SSL_write(conn->ssl, ptr, len);
***************
*** 585,590 ****
--- 622,629 ----                 case EWOULDBLOCK:                     break; #endif
+                 case EINTR:
+                     continue;                  case EPIPE: #ifdef ECONNRESET
***************
*** 616,628 ****             ptr += sent;             len -= sent;         }         if (len > 0)         {
/*We didn't send it all, wait till we can send more */ 
 
-             /* At first glance this looks as though it should block.  I think
-              * that it will be OK though, as long as the socket is
-              * non-blocking. */             if (pqWait(FALSE, TRUE, conn))                 return EOF;         }
--- 655,685 ----             ptr += sent;             len -= sent;         }
+          if (len > 0)         {             /* We didn't send it all, wait till we can send more */
+ 
+             /* 
+              * if the socket is in non-blocking mode we may need
+              * to abort here 
+              */
+ #ifdef USE_SSL
+             /* can't do anything for our SSL users yet */
+             if (conn->ssl == NULL)
+             {
+ #endif
+                 if (PQisnonblocking(conn))
+                 {
+                     /* shift the contents of the buffer */
+                     memmove(conn->outBuffer, ptr, len);
+                     conn->outCount = len;
+                     return EOF;
+                 }
+ #ifdef USE_SSL
+             }
+ #endif              if (pqWait(FALSE, TRUE, conn))                 return EOF;         }
Index: libpq-fe.h
===================================================================
RCS file: /home/pgcvs/pgsql/src/interfaces/libpq/libpq-fe.h,v
retrieving revision 1.53
diff -u -c -r1.53 libpq-fe.h
cvs diff: conflicting specifications of output style
*** libpq-fe.h    1999/11/30 03:08:19    1.53
--- libpq-fe.h    1999/12/14 01:30:01
***************
*** 269,274 ****
--- 269,281 ----     extern int    PQputnbytes(PGconn *conn, const char *buffer, int nbytes);     extern int
PQendcopy(PGconn*conn); 
 
+     /* Set blocking/nonblocking connection to the backend */
+     extern int    PQsetnonblocking(PGconn *conn, int arg);
+     extern int    PQisnonblocking(PGconn *conn);
+ 
+     /* Force the write buffer to be written (or at least try) */
+     extern int    PQflush(PGconn *conn);
+      /*      * "Fast path" interface --- not really recommended for application      * use
Index: libpq-int.h
===================================================================
RCS file: /home/pgcvs/pgsql/src/interfaces/libpq/libpq-int.h,v
retrieving revision 1.14
diff -u -c -r1.14 libpq-int.h
cvs diff: conflicting specifications of output style
*** libpq-int.h    1999/11/30 03:08:19    1.14
--- libpq-int.h    1999/12/14 01:30:01
***************
*** 215,220 ****
--- 215,223 ----     int            inEnd;            /* offset to first position after avail
      * data */ 
 
+     int            nonblocking;    /* whether this connection is using a blocking
+                                  * socket to the backend or not */
+      /* Buffer for data not yet sent to backend */     char       *outBuffer;        /* currently allocated buffer */
   int            outBufSize;        /* allocated size of buffer */