Re: detect custom-format dumps in psql and emit a useful error

<div dir="ltr">Hi,<br /><br />Regarding Loading Custom Format Dump:<br />===<br />When we supply plain sql file to
pg_restore,we get following error:<br />$ ./install/bin/pg_restore a.sql <br />pg_restore: [archiver] input file does
notappear to be a valid archive<br /><br />So I would expect similar kind of message when we provide non-plain sql<br
/>fileto psql. Something like:<br />"input file does not appear to be a valid sql script file<br />(use pg_restore
instead)"<br/><br />I have added additional details in parenthesis as we correctly identified<br />it as a custom dump
fileand user wanted it to restore.<br /><br />However I do not see any issue with the patch.<br /><br /><br />Regarding
DirectoryError:<br />===<br />I strongly against the proposal. This patch changing error message to<br />something like
this:<br/>"psql:blah:0: Input path is a directory. Use pg_restore to restore<br />directory-format database dumps."<br
/><br/>So even though I accidentally provide a directory instead of a sql script<br />file when I have NO intention of
restoringa dump, above message looks<br />weired. Instead current message looks perfectly fine here. i.e.<br />"could
notread from input file: Is a directory"<br /><br />psql always expect a file and NOT directory. Also it is not
necessarily<br/>working on restoring a dump.<br /><br /><br />Thanks<br /></div><div class="gmail_extra"><br /><div
class="gmail_quote">OnFri, Oct 17, 2014 at 9:41 AM, Craig Ringer <span dir="ltr"><<a
href="mailto:craig@2ndquadrant.com"target="_blank">craig@2ndquadrant.com</a>></span> wrote:<br /><blockquote
class="gmail_quote"style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">On 09/18/2014 05:58 PM, Andres
Freundwrote:<br /> > I don't think we need to make any discinction between psql -f mydb.dump,<br /> > psql <
mydb.dump,and whatever | psql. Just check, when noninteractively<br /> > reading the first line in
mainloop.c:MainLoop(),whether it starts with<br /> > the magic header. That'd also trigger the warning on \i
pg_restore_file,<br/> > but that's hardly a problem.<br /><br /> Done, patch attached.<br /><br /> If psql sees that
thefirst line begins with PGDMP it'll emit:<br /><br />   The input is a PostgreSQL custom-format dump. Use the
pg_restore<br/>   command-line client to restore this dump to a database.<br /><br /> then discard the rest of the
currentinput source.<br /><br /> >> pg_restore already knows to tell you to use psql if it sees an SQL file<br />
>>as input. Having something similar for pg_dump would be really useful.<br /> ><br /> > Agreed.<br />
><br/> > We could additionally write out a hint whenever a directory is fed to<br /> > psql -f that psql can't
beused to read directory type dumps.<br /><br /> Unlike the confusion between pg_restore and psql for custom file
format<br/> dumps I haven't seen people getting this one muddled. Perhaps directory<br /> format dumps are just a bit
moreniche, or perhaps it's just more<br /> obvious that:<br /><br /> psql:sometump:0: could not read from input file:
Isa directory<br /><br /> ... means psql is the wrong tool.<br /><br /> Still, separate patch attached. psql will now
emit:<br/><br /> psql:blah:0: Input path is a directory. Use pg_restore to restore<br /> directory-format database
dumps.<br/><br /> I'm less sure that this is a worthwhile improvement than the check for<br /> PGDMP and custom format
dumpsthough.<br /><span class="HOEnZb"><font color="#888888"><br /> --<br />  Craig Ringer                   <a
href="http://www.2ndQuadrant.com/"target="_blank">http://www.2ndQuadrant.com/</a><br />  PostgreSQL Development, 24x7
Support,Training & Services<br /></font></span><br /><br /> --<br /> Sent via pgsql-hackers mailing list (<a
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target="_blank">http://www.postgresql.org/mailpref/pgsql-hackers</a><br/><br /></blockquote></div><br /><br clear="all"
/><br/>-- <br /><div dir="ltr">Jeevan B Chalke<br />Principal Software Engineer, Product Development<br />EnterpriseDB
Corporation<br/>The Enterprise PostgreSQL Company<br /><br />Phone: +91 20 30589500<br /><br />Website: <a
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