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Add support for piping COPY to/from an external program.

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This includes backend "COPY TO/FROM PROGRAM '...'" syntax, and corresponding
psql \copy syntax. Like with reading/writing files, the backend version is
superuser-only, and in the psql version, the program is run in the client.

In the passing, the psql \copy STDIN/STDOUT syntax is subtly changed: if you
the stdin/stdout is quoted, it's now interpreted as a filename. For example,
"\copy foo from 'stdin'" now reads from a file called 'stdin', not from
standard input. Before this, there was no way to specify a filename called
stdin, stdout, pstdin or pstdout.

This creates a new function in pgport, wait_result_to_str(), which can
be used to convert the exit status of a process, as returned by wait(3),
to a human-readable string.

Etsuro Fujita, reviewed by Amit Kapila.
This commit is contained in:
Heikki Linnakangas
2013-02-27 18:17:21 +02:00
parent 73dc003bee
commit 3d009e45bd
21 changed files with 584 additions and 152 deletions
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48
src/backend/parser/gram.y
View File

@ -381,7 +381,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
%type <boolean> opt_freeze opt_default opt_recheck
%type <defelt> opt_binary opt_oids copy_delimiter
%type <boolean> copy_from
%type <boolean> copy_from opt_program
%type <ival> opt_column event cursor_options opt_hold opt_set_data
%type <objtype> reindex_type drop_type comment_type security_label_type
@ -568,7 +568,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
PARSER PARTIAL PARTITION PASSING PASSWORD PLACING PLANS POSITION
PRECEDING PRECISION PRESERVE PREPARE PREPARED PRIMARY
PRIOR PRIVILEGES PROCEDURAL PROCEDURE
PRIOR PRIVILEGES PROCEDURAL PROCEDURE PROGRAM
QUOTE
@ -2309,7 +2309,10 @@ ClosePortalStmt:
*
* QUERY :
* COPY relname [(columnList)] FROM/TO file [WITH] [(options)]
* COPY ( SELECT ... ) TO file [WITH] [(options)]
* COPY ( SELECT ... ) TO file [WITH] [(options)]
*
* where 'file' can be one of:
* { PROGRAM 'command' | STDIN | STDOUT | 'filename' }
*
* In the preferred syntax the options are comma-separated
* and use generic identifiers instead of keywords. The pre-9.0
@ -2324,14 +2327,21 @@ ClosePortalStmt:
*****************************************************************************/
CopyStmt: COPY opt_binary qualified_name opt_column_list opt_oids
copy_from copy_file_name copy_delimiter opt_with copy_options
copy_from opt_program copy_file_name copy_delimiter opt_with copy_options
{
CopyStmt *n = makeNode(CopyStmt);
n->relation = $3;
n->query = NULL;
n->attlist = $4;
n->is_from = $6;
n->filename = $7;
n->is_program = $7;
n->filename = $8;
if (n->is_program && n->filename == NULL)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("STDIN/STDOUT not allowed with PROGRAM"),
parser_errposition(@8)));
n->options = NIL;
/* Concatenate user-supplied flags */
@ -2339,21 +2349,29 @@ CopyStmt: COPY opt_binary qualified_name opt_column_list opt_oids
n->options = lappend(n->options, $2);
if ($5)
n->options = lappend(n->options, $5);
if ($8)
n->options = lappend(n->options, $8);
if ($10)
n->options = list_concat(n->options, $10);
if ($9)
n->options = lappend(n->options, $9);
if ($11)
n->options = list_concat(n->options, $11);
$$ = (Node *)n;
}
| COPY select_with_parens TO copy_file_name opt_with copy_options
| COPY select_with_parens TO opt_program copy_file_name opt_with copy_options
{
CopyStmt *n = makeNode(CopyStmt);
n->relation = NULL;
n->query = $2;
n->attlist = NIL;
n->is_from = false;
n->filename = $4;
n->options = $6;
n->is_program = $4;
n->filename = $5;
n->options = $7;
if (n->is_program && n->filename == NULL)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("STDIN/STDOUT not allowed with PROGRAM"),
parser_errposition(@5)));
$$ = (Node *)n;
}
;
@ -2363,6 +2381,11 @@ copy_from:
| TO { $$ = FALSE; }
;
opt_program:
PROGRAM { $$ = TRUE; }
| /* EMPTY */ { $$ = FALSE; }
;
/*
* copy_file_name NULL indicates stdio is used. Whether stdin or stdout is
* used depends on the direction. (It really doesn't make sense to copy from
@ -12666,6 +12689,7 @@ unreserved_keyword:
| PRIVILEGES
| PROCEDURAL
| PROCEDURE
| PROGRAM
| QUOTE
| RANGE
| READ