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Fix some shortcomings in psql's autocommit-off mode concerning detection

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of commands for which a transaction block should not be forced.  Recognize
VACUUM and other PreventTransactionChain commands; handle nested /* .. */
comments correctly; handle multibyte encodings correctly.
Michael Paesold with some kibitzing from Tom Lane.
REL8_0_STABLE
Tom Lane 22 years ago
parent 9332d0baba
commit 5b564e5307
2 changed files with 110 additions and 27 deletions
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
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  1. 5
      doc/src/sgml/ref/psql-ref.sgml
  2. 132
      src/bin/psql/common.c

5
doc/src/sgml/ref/psql-ref.sgml
Unescape View File

@ -1,5 +1,5 @@
<!--
$PostgreSQL: pgsql/doc/src/sgml/ref/psql-ref.sgml,v 1.121 2004/08/24 00:06:51 neilc Exp $
$PostgreSQL: pgsql/doc/src/sgml/ref/psql-ref.sgml,v 1.122 2004/09/20 18:51:17 tgl Exp $
PostgreSQL documentation
-->
@ -1875,7 +1875,8 @@ bar
mode works by issuing an implicit <command>BEGIN</> for you, just
before any command that is not already in a transaction block and
is not itself a <command>BEGIN</> or other transaction-control
command.
command, nor a command that cannot be executed inside a transaction
block (such as <command>VACUUM</>).
</para>
<note>

132
src/bin/psql/common.c
Unescape View File

@ -3,7 +3,7 @@
*
* Copyright (c) 2000-2004, PostgreSQL Global Development Group
*
* $PostgreSQL: pgsql/src/bin/psql/common.c,v 1.90 2004/08/29 05:06:54 momjian Exp $
* $PostgreSQL: pgsql/src/bin/psql/common.c,v 1.91 2004/09/20 18:51:19 tgl Exp $
*/
#include "postgres_fe.h"
#include "common.h"
@ -62,7 +62,7 @@ typedef struct _timeb TimevalStruct;
extern bool prompt_state;
static bool is_transact_command(const char *query);
static bool command_no_begin(const char *query);
/*
@ -895,7 +895,7 @@ SendQuery(const char *query)
if (PQtransactionStatus(pset.db) == PQTRANS_IDLE &&
!GetVariableBool(pset.vars, "AUTOCOMMIT") &&
!is_transact_command(query))
!command_no_begin(query))
{
results = PQexec(pset.db, "BEGIN");
if (PQresultStatus(results) != PGRES_COMMAND_OK)
@ -946,65 +946,147 @@ SendQuery(const char *query)
return OK;
}
/*
* check whether a query string begins with BEGIN/COMMIT/ROLLBACK/START XACT
* Advance the given char pointer over white space and SQL comments.
*/
static bool
is_transact_command(const char *query)
static const char *
skip_white_space(const char *query)
{
int wordlen;
int cnestlevel = 0; /* slash-star comment nest level */
/*
* First we must advance over any whitespace and comments.
*/
while (*query)
{
int mblen = PQmblen(query, pset.encoding);
/*
* Note: we assume the encoding is a superset of ASCII, so that
* for example "query[0] == '/'" is meaningful. However, we do NOT
* assume that the second and subsequent bytes of a multibyte
* character couldn't look like ASCII characters; so it is critical
* to advance by mblen, not 1, whenever we haven't exactly identified
* the character we are skipping over.
*/
if (isspace((unsigned char) *query))
query++;
else if (query[0] == '-' && query[1] == '-')
query += mblen;
else if (query[0] == '/' && query[1] == '*')
{
cnestlevel++;
query += 2;
while (*query && *query != '\n')
query++;
}
else if (query[0] == '/' && query[1] == '*')
else if (cnestlevel > 0 && query[0] == '*' && query[1] == '/')
{
cnestlevel--;
query += 2;
}
else if (cnestlevel == 0 && query[0] == '-' && query[1] == '-')
{
query += 2;
/*
* We have to skip to end of line since any slash-star inside
* the -- comment does NOT start a slash-star comment.
*/
while (*query)
{
if (query[0] == '*' && query[1] == '/')
if (*query == '\n')
{
query += 2;
query++;
break;
}
else
query++;
query += PQmblen(query, pset.encoding);
}
}
else if (cnestlevel > 0)
query += mblen;
else
break; /* found first token */
}
return query;
}
/*
* Check whether a command is one of those for which we should NOT start
* a new transaction block (ie, send a preceding BEGIN).
*
* These include the transaction control statements themselves, plus
* certain statements that the backend disallows inside transaction blocks.
*/
static bool
command_no_begin(const char *query)
{
int wordlen;
/*
* Check word length ("beginx" is not "begin").
* First we must advance over any whitespace and comments.
*/
query = skip_white_space(query);
/*
* Check word length (since "beginx" is not "begin").
*/
wordlen = 0;
while (isalpha((unsigned char) query[wordlen]))
wordlen++;
wordlen += PQmblen(&query[wordlen], pset.encoding);
/*
* Transaction control commands. These should include every keyword
* that gives rise to a TransactionStmt in the backend grammar, except
* for the savepoint-related commands.
*
* (We assume that START must be START TRANSACTION, since there is
* presently no other "START foo" command.)
*/
if (wordlen == 5 && pg_strncasecmp(query, "abort", 5) == 0)
return true;
if (wordlen == 5 && pg_strncasecmp(query, "begin", 5) == 0)
return true;
if (wordlen == 5 && pg_strncasecmp(query, "start", 5) == 0)
return true;
if (wordlen == 6 && pg_strncasecmp(query, "commit", 6) == 0)
return true;
if (wordlen == 8 && pg_strncasecmp(query, "rollback", 8) == 0)
if (wordlen == 3 && pg_strncasecmp(query, "end", 3) == 0)
return true;
if (wordlen == 5 && pg_strncasecmp(query, "abort", 5) == 0)
if (wordlen == 8 && pg_strncasecmp(query, "rollback", 8) == 0)
return true;
if (wordlen == 3 && pg_strncasecmp(query, "end", 3) == 0)
/*
* Commands not allowed within transactions. The statements checked
* for here should be exactly those that call PreventTransactionChain()
* in the backend.
*
* Note: we are a bit sloppy about CLUSTER, which is transactional in
* some variants but not others.
*/
if (wordlen == 6 && pg_strncasecmp(query, "vacuum", 6) == 0)
return true;
if (wordlen == 5 && pg_strncasecmp(query, "start", 5) == 0)
if (wordlen == 7 && pg_strncasecmp(query, "cluster", 7) == 0)
return true;
/*
* Note: these tests will match REINDEX TABLESPACE, which isn't really
* a valid command so we don't care much. The other five possible
* matches are correct.
*/
if ((wordlen == 6 && pg_strncasecmp(query, "create", 6) == 0) ||
(wordlen == 4 && pg_strncasecmp(query, "drop", 4) == 0) ||
(wordlen == 7 && pg_strncasecmp(query, "reindex", 7) == 0))
{
query += wordlen;
query = skip_white_space(query);
wordlen = 0;
while (isalpha((unsigned char) query[wordlen]))
wordlen += PQmblen(&query[wordlen], pset.encoding);
if (wordlen == 8 && pg_strncasecmp(query, "database", 8) == 0)
return true;
if (wordlen == 10 && pg_strncasecmp(query, "tablespace", 10) == 0)
return true;
}
return false;
}

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