[tracker/wip/carlosg/serialize-api: 13/13] docs: Document how the annotated types in cursors affect limits

[Carlos Garnacho <carlosg src gnome org>]

commit 773ea70191accd92f264dc098005291a868c3c07
Author: Carlos Garnacho <carlosg gnome org>
Date:   Wed Feb 2 14:01:23 2022 +0100

    docs: Document how the annotated types in cursors affect limits
    
    SELECTs may have 2000 columns, which we effectively halve with SPARQL
    queries doubling the number of columns. Still, 1000 is an acceptable
    default limit, and the change is unlikely to have side effects, so
    document this new behavior.

 docs/reference/libtracker-sparql/limits.md | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)
---
diff --git a/docs/reference/libtracker-sparql/limits.md b/docs/reference/libtracker-sparql/limits.md
index 120b1c7c4..9d514b834 100644
--- a/docs/reference/libtracker-sparql/limits.md
+++ b/docs/reference/libtracker-sparql/limits.md
@@ -16,12 +16,17 @@ options.
 Tracker can store by default up to 1 GiB in a text field by default. This
 limit is controlled by `SQLITE_MAX_LENGTH`
 
-## Maximum number of properties
+## Maximum number of properties and select columns
 
 The maximum amount of properties in the domain of a single class, and
 the maximum number of global fulltext-search properties in the ontology
 are limited by `SQLITE_MAX_COLUMN` (defaults to 2000).
 
+Each column in the result set of a SELECT query contains additional
+information included as an additional column, so the limit of columns
+that can be retrieved in a single SELECT query is effectively half
+of `SQLITE_MAX_COLUMN` (1000 with the default settings).
+
 ## Underlying parser limits
 
 SQLite defines some limits to its parser. Maximum query length is 1 MiB,