[WaitWaitWha]

> To solve these problems, Umbra, the research predecessor of CedarDB, invented what Andy Pavlo now affectionately (we assume ;)) calls “German-style strings”.

This is how Borland Turbo Pascal stored strings as far back as the first version in mid-80s.

Length followed by the string.

[f1shy]

I think is about the kind of union they use, to store it differently depending on the string length, not the fact of length+data. Anyway is/was also nothing remotely new (the idea) as many lisp and scheme implementations have done so for strings and numbers basically for ages.

[mau]

German-style strings is a way to store array of strings for columnar dbs. The idea is to have an array of metadata. Metadata has a fixed size (16 bytes) The metadata includes the string length and either a pair of pointer + string prefix or the full string for short strings. For some operations the string prefix is enough in many cases avoiding the indirection.

This is different from Pascal strings.

[afandian]

Storing the prefix and the tagged union of pointer and inline data structure is big difference to Pascal strings though.

[xnorswap]

That's not what it's doing though.

Pascal strings are: { length, pointer }

In these strings:

For short strings it's storing:

  { length, string value}

for longer strings, it's storing

  {length, prefix, class, pointer }

[masklinn]

> Pascal strings are: { length, pointer }

The historical P-strings are just a pointer, with the length at the head of the buffer. Hence length-prefixed strings, and their limitation to 255 bytes (only one byte was reserved for the length, you can still see this in the most base string of freepascal: https://www.freepascal.org/docs-html/ref/refsu9.html).

    {length, pointer}

or

    {length, capacity, pointer}

is struct / record strings, and what pretty much every modern language does (possibly with optimisations e.g. SSO23 is basically a p-string when inline, but can move out of line into a full record string).