Add Unable To Infer Data Type In Production as a Postgres TIL

README.md

@@ -10,7 +10,7 @@ pairing with smart people at Hashrocket.
 
 For a steady stream of TILs, [sign up for my newsletter](https://crafty-builder-6996.ck.page/e169c61186).
 
-_1577 TILs and counting..._
+_1579 TILs and counting..._
 
 See some of the other learning resources I work on:
 - [Ruby Operator Lookup](https://www.visualmode.dev/ruby-operators)
@@ -905,6 +905,7 @@ See some of the other learning resources I work on:
 - [Two Ways To Compute Factorial](postgres/two-ways-to-compute-factorial.md)
 - [Two Ways To Escape A Quote In A String](postgres/two-ways-to-escape-a-quote-in-a-string.md)
 - [Types By Category](postgres/types-by-category.md)
+- [Unable To Infer Data Type In Production](postgres/unable-to-infer-data-type-in-production.md)
 - [Union All Rows Including Duplicates](postgres/union-all-rows-including-duplicates.md)
 - [Use A psqlrc File For Common Settings](postgres/use-a-psqlrc-file-for-common-settings.md)
 - [Use A Trigger To Mirror Inserts To Another Table](postgres/use-a-trigger-to-mirror-inserts-to-another-table.md)
@@ -1074,6 +1075,7 @@ See some of the other learning resources I work on:
 - [Set DateTime To Include Time Zone In Migrations](rails/set-datetime-to-include-time-zone-in-migrations.md)
 - [Set Default As SQL Function In Migration](rails/set-default-as-sql-function-in-migration.md)
 - [Set default_url_options For Entire Application](rails/set-default-url-options-for-entire-application.md)
+- [Set Meta Tags In ERB Views](rails/set-meta-tags-in-erb-views.md)
 - [Set Schema Search Path](rails/set-schema-search-path.md)
 - [Set Statement Timeout For All Postgres Connections](rails/set-statement-timeout-for-all-postgres-connections.md)
 - [Set The Default Development Port](rails/set-the-default-development-port.md)

postgres/unable-to-infer-data-type-in-production.md

@@ -0,0 +1,45 @@
+# Unable To Infer Data Type In Production
+
+Inspired by [You Probably Don't Need Query
+Builders](https://mattrighetti.com/2025/01/20/you-dont-need-sql-builders), I
+wrote a query in one of my applications that has filter clauses that get
+short-circuited if the filter value hasn't been included.
+
+That query looked something like this:
+
+```ruby
+@tags =
+  Tag.where("? is null or normalized_value ilike ?", normalized_query, "%#{normalized_query}%")
+     .order(:normalized_value)
+     .limit(10)
+```
+
+The `normalized_value ilike ?` filtering won't be applied if the
+`normalized_query` value isn't present (`nil`). This helps me avoid writing
+messy ternaries or if-else conditional query building madness.
+
+Unfortunately, when I shipped this query to production, the page started
+failing and Postgres was reporting this error in the logs.
+
+```
+Caused by: PG::IndeterminateDatatype (ERROR:  could not determine data type of parameter $1)
+```
+
+The query is prepared as a parameterized statement and Postgres appears to be
+unable to determine the datatype of the first parameter (`$1`) —
+`normalized_query`.
+
+I was unable to reproduce the issue in development. It was only occuring in
+production. Until I can come up with a root cause analysis, I have the
+following fix that does a casting to `text`. This helps out with the type
+inference and makes the issue go away.
+
+```ruby
+@tags =
+  Tag.where("cast(? as text) is null or normalized_value ilike ?", normalized_query, "%#{normalized_query}%")
+     .order(:normalized_value)
+     .limit(10)
+```
+
+Interestingly, this person using `pgtyped` [ran into the exact same issue with
+the same type of query](https://github.com/adelsz/pgtyped/issues/354).

rails/set-meta-tags-in-erb-views.md

@@ -0,0 +1,52 @@
+# Set Meta Tags In ERB Views
+
+There are all kinds of meta tags that we may want to set for the pages that our
+Rails app serves. A lot of these are for SEO and social sharing. Let's look at
+how to add `og:description` meta tags to our views.
+
+I'll start with a helper method in `app/helpers/application_helper.rb`:
+
+```ruby
+module ApplicationHelper
+  def meta_description(desc)
+    content_for(:description) { desc }
+  end
+end
+```
+
+Then, I'll update my `app/views/layouts/application.html.erb` to consume the
+description when provided.
+
+```ruby
+<!DOCTYPE html>
+<html>
+  <head>
+    <!-- ... -->
+
+    <meta
+      property="og:description"
+      content="<%= content_for?(:description) ? yield(:description) : 'Default description' %>"
+    >
+
+    <!-- ... -->
+  </head>
+
+  <!-- ... -->
+</html>
+```
+
+Now I have a default description for all my views that I can override as needed
+with the `meta_description` helper.
+
+```ruby
+# app/views/posts/show.html.erb
+<%= meta_description @post.body.split("\n").first %>
+
+<!-- ... -->
+```
+
+If I reload the page and inspect the meta tags in `<head>`, I should find the
+`og:description` tag with the corresponding value.
+
+This can be extended to apply all the different meta tags (e.g. Open Graph and
+Twitter) to make links to these pages render well across the internet.