The BibTeX diagnostic "Warning-you've exceeded 1000, the
global-string-size, for entry foo" usually arises from a very
large abstract or annotation included in the database. The diagnostic
usually arises because of an infelicity in the coding of
abstract.bst, or styles derived from it. (One doesn't
ordinarily output annotations in other styles.)
The solution is to make a copy of the style file (or get a clean copy
from CTAN - biblio/bibtex/contrib/abstract.bst), and rename it (e.g., on a
long file-name system to abstract-long.bst). Now edit it: find
function output.nonnull and
"{ 's :=" to "{ swap$", and
"s" (line 84 in the
version on CTAN).
\bibliographystyle command to refer to the
name of the new file.
This technique applies equally to any bibliography style: the same
change can be made to any similar output.nonnull function.
If you're reluctant to make this sort of change, the only way forward is to take the entry out of the database, so that you don't encounter BibTeX's limit, but you may need to retain the entry because it will be included in the typeset document. In such cases, put the body of the entry in a separate file:
@article{long.boring,
author = "Fred Verbose",
...
abstract = "{\input{abstracts/long.tex}}"
}
In this way, you arrange that all BibTeX has to deal with is the
file name, though it will tell TeX (when appropriate) to include
all the long text.