Fix pg_restore's direct-to-database mode for INSERT-style table data.

In commit 6545a901aaf84cb05212bb6a7674059908f527c3, I removed the mini SQL
lexer that was in pg_backup_db.c, thinking that it had no real purpose
beyond separating COPY data from SQL commands, which purpose had been
obsoleted by long-ago fixes in pg_dump's archive file format.
Unfortunately this was in error: that code was also used to identify
command boundaries in INSERT-style table data, which is run together as a
single string in the archive file for better compressibility.  As a result,
direct-to-database restores from archive files made with --inserts or
--column-inserts fail in our latest releases, as reported by Dick Visser.

To fix, restore the mini SQL lexer, but simplify it by adjusting the
calling logic so that it's only required to cope with INSERT-style table
data, not arbitrary SQL commands.  This allows us to not have to deal with
SQL comments, E'' strings, or dollar-quoted strings, none of which have
ever been emitted by dumpTableData_insert.

Also, fix the lexer to cope with standard-conforming strings, which was the
actual bug that the previous patch was meant to solve.

Back-patch to all supported branches.  The previous patch went back to 8.2,
which unfortunately means that the EOL release of 8.2 contains this bug,
but I don't think we're doing another 8.2 release just because of that.

1 files changed, 89 insertions, 1 deletions

diff --git a/src/bin/pg_dump/pg_backup_db.c b/src/bin/pg_dump/pg_backup_db.c
index bd1b8efac82..62c8b3356c6 100644
--- a/src/bin/pg_dump/pg_backup_db.c
+++ b/src/bin/pg_dump/pg_backup_db.c
@@ -365,14 +365,92 @@ ExecuteSqlCommand(ArchiveHandle *AH, const char *qry, const char *desc)
 
 
 /*
+ * Process non-COPY table data (that is, INSERT commands).
+ *
+ * The commands have been run together as one long string for compressibility,
+ * and we are receiving them in bufferloads with arbitrary boundaries, so we
+ * have to locate command boundaries and save partial commands across calls.
+ * All state must be kept in AH->sqlparse, not in local variables of this
+ * routine.  We assume that AH->sqlparse was filled with zeroes when created.
+ *
+ * We have to lex the data to the extent of identifying literals and quoted
+ * identifiers, so that we can recognize statement-terminating semicolons.
+ * We assume that INSERT data will not contain SQL comments, E'' literals,
+ * or dollar-quoted strings, so this is much simpler than a full SQL lexer.
+ */
+static void
+ExecuteInsertCommands(ArchiveHandle *AH, const char *buf, size_t bufLen)
+{
+	const char *qry = buf;
+	const char *eos = buf + bufLen;
+
+	/* initialize command buffer if first time through */
+	if (AH->sqlparse.curCmd == NULL)
+		AH->sqlparse.curCmd = createPQExpBuffer();
+
+	for (; qry < eos; qry++)
+	{
+		char	ch = *qry;
+
+		/* For neatness, we skip any newlines between commands */
+		if (!(ch == '\n' && AH->sqlparse.curCmd->len == 0))
+			appendPQExpBufferChar(AH->sqlparse.curCmd, ch);
+
+		switch (AH->sqlparse.state)
+		{
+			case SQL_SCAN:		/* Default state == 0, set in _allocAH */
+				if (ch == ';')
+				{
+					/*
+					 * We've found the end of a statement. Send it and reset
+					 * the buffer.
+					 */
+					ExecuteSqlCommand(AH, AH->sqlparse.curCmd->data,
+									  "could not execute query");
+					resetPQExpBuffer(AH->sqlparse.curCmd);
+				}
+				else if (ch == '\'')
+				{
+					AH->sqlparse.state = SQL_IN_SINGLE_QUOTE;
+					AH->sqlparse.backSlash = false;
+				}
+				else if (ch == '"')
+				{
+					AH->sqlparse.state = SQL_IN_DOUBLE_QUOTE;
+				}
+				break;
+
+			case SQL_IN_SINGLE_QUOTE:
+				/* We needn't handle '' specially */
+				if (ch == '\'' && !AH->sqlparse.backSlash)
+					AH->sqlparse.state = SQL_SCAN;
+				else if (ch == '\\' && !AH->public.std_strings)
+					AH->sqlparse.backSlash = !AH->sqlparse.backSlash;
+				else
+					AH->sqlparse.backSlash = false;
+				break;
+
+			case SQL_IN_DOUBLE_QUOTE:
+				/* We needn't handle "" specially */
+				if (ch == '"')
+					AH->sqlparse.state = SQL_SCAN;
+				break;
+		}
+	}
+}
+
+
+/*
  * Implement ahwrite() for direct-to-DB restore
  */
 int
 ExecuteSqlCommandBuf(ArchiveHandle *AH, const char *buf, size_t bufLen)
 {
-	if (AH->writingCopyData)
+	if (AH->outputKind == OUTPUT_COPYDATA)
 	{
 		/*
+		 * COPY data.
+		 *
 		 * We drop the data on the floor if libpq has failed to enter COPY
 		 * mode; this allows us to behave reasonably when trying to continue
 		 * after an error in a COPY command.
@@ -382,9 +460,19 @@ ExecuteSqlCommandBuf(ArchiveHandle *AH, const char *buf, size_t bufLen)
 			die_horribly(AH, modulename, "error returned by PQputCopyData: %s",
 						 PQerrorMessage(AH->connection));
 	}
+	else if (AH->outputKind == OUTPUT_OTHERDATA)
+	{
+		/*
+		 * Table data expressed as INSERT commands.
+		 */
+		ExecuteInsertCommands(AH, buf, bufLen);
+	}
 	else
 	{
 		/*
+		 * General SQL commands; we assume that commands will not be split
+		 * across calls.
+		 *
 		 * In most cases the data passed to us will be a null-terminated
 		 * string, but if it's not, we have to add a trailing null.
 		 */