Re: Empty string in lexeme for tsvector

From: Jean-Christophe Arnu <jcarnu(at)gmail(dot)com>
To: Ranier Vilela <ranier(dot)vf(at)gmail(dot)com>
Cc: PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org>
Subject: Re: Empty string in lexeme for tsvector
Date: 2021-09-24 12:39:31
Message-ID: CAHZmTm2RNbzrQnPupvXfT_TgLn1Vj67g4dPE1_uD9p-cogYh=Q@mail.gmail.com
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Le ven. 24 sept. 2021 à 13:03, Ranier Vilela <ranier(dot)vf(at)gmail(dot)com> a écrit :

>
> Comments are more than welcome!
>>
> 1. Would be better to add this test-and-error before tsvector_bsearch call.
>
> + if (lex_len == 0)
> + ereport(ERROR,
> + (errcode(ERRCODE_ZERO_LENGTH_CHARACTER_STRING),
> + errmsg("lexeme array may not contain empty strings")));
> +
>
> If lex_len is equal to zero, better get out soon.
>
> 2. The second test-and-error can use lex_len, just like the first test,
> I don't see the point in recalculating the size of lex_len if that's
> already done.
>
> + if (VARSIZE(dlexemes[i]) - VARHDRSZ == 0)
> + ereport(ERROR,
> + (errcode(ERRCODE_ZERO_LENGTH_CHARACTER_STRING),
> + errmsg("lexeme array may not contain empty strings")));
> +
>

Hello Ranier,
Thank you for your comments.
Here's a new patch file taking your comments into account.

I was just wondering if empty string eviction is done in the right place.
As you rightfully commented, lex_len is calculated later (once again for a
right purpose) and my code checks for empty strings as soon as possible.
To me, it seems to be the right thing to do (prevent further processing on
lexemes
as soon as possible) but I might omit something.

Regards

Jean-Christophe Arnu

Attachment Content-Type Size
empty_string_in_tsvector_v1.patch text/x-patch 5.5 KB

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