Additional functions for SQL compatibility

[blinkov]

• left/right
• trim/ltrim/rtrim
• timestampadd/timestampsub
• other interval-relarted improvements
• additional case insensitive functions

#3712 #3714 #3704 #3705

[alexey-milovidov]

Separate function should be both more simple and more efficient.

[blinkov]

It appeared that substring with negative second argument does exactly what right is supposed to, so I just simplified this aliasing.

[alexey-milovidov]

I mean we need separate functions trim, trimLeft, trimRight with fairly efficient implementation.

[blinkov]

See b7566a8, looks roughly like this for 16Gb of text with a lot of whitespace:

    "runs": [
        {
            "min_time": 1.224000,
            "query": "SELECT count() FROM whitespaces WHERE NOT ignore(value)"
        },
        {
            "min_time": 2.019000,
            "query": "SELECT count() FROM whitespaces WHERE NOT ignore(trimLeft(value))"
        },
        {
            "min_time": 1.979000,
            "query": "SELECT count() FROM whitespaces WHERE NOT ignore(trimRight(value))"
        },
        {
            "min_time": 1.991000,
            "query": "SELECT count() FROM whitespaces WHERE NOT ignore(trimBoth(value))"
        },
        {
            "min_time": 5.121000,
            "query": "SELECT count() FROM whitespaces WHERE NOT ignore(replaceRegexpOne(value, '^ *', ''))"
        },
        {
            "min_time": 8.320000,
            "query": "SELECT count() FROM whitespaces WHERE NOT ignore(replaceRegexpOne(value, ' *$', ''))"
        },
        {
            "min_time": 12.282000,
            "query": "SELECT count() FROM whitespaces WHERE NOT ignore(replaceRegexpAll(value, '^ *| *$', ''))"
        }
    ]

[alexey-milovidov]

No test for regexpQuoteMeta?

[blinkov]

@alexey-milovidov there's a test for it's implicit call from one of trim variants

[alexey-milovidov]

mtlog-perftest03j.yandex.ru :) SELECT URL FROM hits_1000m_transformed WHERE URL != regexpQuoteMeta(URL) LIMIT 100

SELECT URL
FROM hits_1000m_transformed 
WHERE URL != regexpQuoteMeta(URL)
LIMIT 100

Received exception from server (version 18.14.17):
Code: 241. DB::Exception: Received from localhost:9000, ::1. DB::Exception: Memory limit (for query) exceeded: would use 16.03 GiB (attempt to allocate chunk of 8589934592 bytes), maximum: 9.31 GiB.