gudusoft.gsqlparser.parser

Class CreateTableAsSelectRecovery

Object

gudusoft.gsqlparser.parser.CreateTableAsSelectRecovery

public final class CreateTableAsSelectRecovery
extends Object

Error recovery for a Doris or StarRocks CREATE TABLE ... AS SELECT whose table clauses the grammar cannot read.

When a CREATE TABLE fails to parse, the general recovery ignores everything after the first closing parenthesis at depth zero and parses the statement again, so a table whose column list is followed by an unsupported option still yields its columns. For a CREATE TABLE AS SELECT that ignores the query too, and with it every lineage edge of the statement, while the statement reports success. When the first closing parenthesis belongs to an option, as in DUPLICATE KEY(k1), or to the query itself, the result is a query cut short.

This recovery keeps the header and the query and ignores only the table clauses between them: CREATE TABLE t DUPLICATE KEY(k1) DISTRIBUTED BY HASH(k1) AS SELECT ... is parsed as CREATE TABLE t AS SELECT .... When nothing stands between the header and the query, the error lies in one of them and is kept.

Used by both parse paths, TGSqlParser and the vendor SqlParser, so that they recover in the same way. Not intended for use outside the parser.

Method Summary

Modifier and Type	Method and Description
static boolean	ignoreClausesBeforeQuery(TSourceTokenList tokens, int queryStart) Ignores the table clauses between the header and the query, so that the grammar reads both even when it cannot read a clause in between (an OLAP key, a partition or distribution clause, properties, ...).
static int	queryStart(TSourceTokenList tokens) Position of the AS that starts the query of a CREATE TABLE AS SELECT: the first AS at parenthesis depth zero that is followed by SELECT, WITH or an opening parenthesis, or -1 when the statement has no query.

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

queryStart

public static int queryStart(TSourceTokenList tokens)

Position of the AS that starts the query of a CREATE TABLE AS SELECT: the first AS at parenthesis depth zero that is followed by SELECT, WITH or an opening parenthesis, or -1 when the statement has no query. A generated column (k2 INT AS k1 + 1) sits inside the column list, one level deep, so it is never taken for the query.

Parameters:

tokens - the tokens of one CREATE TABLE statement

Returns:

the position of the AS in tokens, or -1

ignoreClausesBeforeQuery

public static boolean ignoreClausesBeforeQuery(TSourceTokenList tokens,
                                               int queryStart)

Ignores the table clauses between the header and the query, so that the grammar reads both even when it cannot read a clause in between (an OLAP key, a partition or distribution clause, properties, ...).

Parameters:

tokens - the tokens of one CREATE TABLE statement

queryStart - the position returned by queryStart(gudusoft.gsqlparser.TSourceTokenList)

Returns:

true when a clause was ignored and the statement must be parsed again; false when nothing stands between the header and the query, or the header was not found, so the tokens are unchanged and the error is kept