CREATE REPLICATION SLOT fails on a timeout

I am finding that my logical walsender connections are being terminated
due to a timeout on the CREATE REPLICATION SLOT command. with
"terminating walsender process due to replication timeout"

Below is the stack trace when this happens

#3  0x000000000067df28 in WalSndCheckTimeOut
(now=now@entry=453585463823871) at walsender.c:1748
#4  0x000000000067eedc in WalSndWaitForWal (loc=691727888) at
walsender.c:1216
#5  logical_read_xlog_page (state=<optimized out>,
targetPagePtr=691724288, reqLen=<optimized out>,
     targetRecPtr=<optimized out>, cur_page=0x18476e0 "}\320\005",
pageTLI=<optimized out>) at walsender.c:741
#6  0x00000000004f41bf in ReadPageInternal (state=state@entry=0x17aa140,
pageptr=pageptr@entry=691724288,
     reqLen=reqLen@entry=3600) at xlogreader.c:525
#7  0x00000000004f454a in XLogReadRecord (state=0x17aa140,
RecPtr=691727856, RecPtr@entry=0,
     errormsg=errormsg@entry=0x7fff7f668c28) at xlogreader.c:228
#8  0x0000000000675e5c in DecodingContextFindStartpoint
(ctx=ctx@entry=0x17a0358) at logical.c:460
#9  0x0000000000680f16 in CreateReplicationSlot (cmd=0x1798b50) at
walsender.c:800
#10 exec_replication_command (
     cmd_string=cmd_string@entry=0x17f1478 "CREATE_REPLICATION_SLOT
\"slon_4_1\" LOGICAL \"slony1_funcs.2.2.0\"")
     at walsender.c:1291
#11 0x00000000006bf4a1 in PostgresMain (argc=<optimized out>,
argv=argv@entry=0x177db50, dbname=0x177db30 "test1",

(gdb) p last_reply_timestamp
$1 = 0


I propose the attached patch sets last_reply_timestamp to now() it
starts processing a command.  Since receiving a command is hearing
something from the client.


Steve