Re: [BUGS] Beta 10 parser error for CREATE STATISTICS IF NOT EXISTS

On 2017/06/21 10:15, Amit Langote wrote:
> On 2017/06/21 9:42, Bruno Wolff III wrote:
>> I'm not seeing an obvious error in my attempt to use CREATE STATISTICS IF
>> NOT EXISTS. Given this is new, maybe there is a bug in the parser.
>>
>> Sample output:
>> psql (10beta1)
>> Type "help" for help.
>>
>> o365logs=# select version();
>>
>> version
>> --------------------------------------------------------------------------------
>>
>> ----------------------------
>> PostgreSQL 10beta1 on x86_64-pc-linux-gnu, compiled by gcc (GCC) 4.8.5
>> 20150623
>> (Red Hat 4.8.5-11), 64-bit
>> (1 row)
>>
>> o365logs=# CREATE STATISTICS IF NOT EXISTS logs_corrtest (dependencies) ON
>> record_type, operation FROM logs;
>> ERROR: syntax error at or near "NOT"
>> LINE 1: CREATE STATISTICS IF NOT EXISTS logs_corrtest (dependencies)...
>
> Looks like a documentation bug if the authors of the feature actually
> meant to implement the following syntax:
>
> CREATE [ IF NOT EXISTS ] STATISTICS
>
> create if not exists statistics words_stats on a, b from words;
> CREATE STATISTICS
>
> create if not exists statistics words_stats on a, b from words;
> NOTICE: statistics object "words_stats" already exists, skipping
> CREATE STATISTICS
>
> If that's really what's intended, it seems a bit inconsistent with most
> other commands and with DROP STATISTICS [ IF NOT EXISTS ] itself.

Here is a patch, just in case, that changes the grammar to accept the
following syntax instead of the current one:

CREATE STATISTICS [ IF NOT EXIST ] ...

Also added a test. Documentation already displays the above syntax, so no
update needed there.

Thanks,
Amit