From d8d468a97fb4d2a6cdaee5c4e9fca5f0958da984 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jos=C3=A9=20Valim?= <jose.valim@dashbit.co>
Date: Fri, 17 Apr 2020 19:32:30 +0200
Subject: [PATCH] Allow cache statement to be per operation instead

Closes https://github.com/elixir-ecto/ecto/issues/3284.
---
 lib/ecto/adapters/myxql.ex    |  4 ++++
 lib/ecto/adapters/postgres.ex |  4 ++++
 lib/ecto/adapters/sql.ex      | 14 ++++++++++----
 lib/ecto/adapters/tds.ex      |  7 +++++++
 4 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/lib/ecto/adapters/myxql.ex b/lib/ecto/adapters/myxql.ex
index 839633ff..b7bdb7d7 100644
--- a/lib/ecto/adapters/myxql.ex
+++ b/lib/ecto/adapters/myxql.ex
@@ -28,6 +28,10 @@ defmodule Ecto.Adapters.MyXQL do
       This option is only used for `mix ecto.load` and `mix ecto.dump`,
       via the `mysql` command. For more information, please check
       [MySQL docs](https://dev.mysql.com/doc/en/connecting.html)
+    * `:cache_statement` - how Ecto should cache INSERT/UPDATE/DELETE statements.
+      It can either be `:per_schema` (one cache key is used for each schema) or
+      `:per_operation` (one cache key is use for each operation). Note SELECTs
+      use a more complete cache mechanism that considers the query itself.
     * `:socket_options` - Specifies socket configuration
     * `:show_sensitive_data_on_connection_error` - show connection data and
       configuration whenever there is an error attempting to connect to the
diff --git a/lib/ecto/adapters/postgres.ex b/lib/ecto/adapters/postgres.ex
index 44ccf99f..5f56f2b2 100644
--- a/lib/ecto/adapters/postgres.ex
+++ b/lib/ecto/adapters/postgres.ex
@@ -40,6 +40,10 @@ defmodule Ecto.Adapters.Postgres do
     * `:ssl` - Set to true if ssl should be used (default: false)
     * `:ssl_opts` - A list of ssl options, see Erlang's `ssl` docs
     * `:parameters` - Keyword list of connection parameters
+    * `:cache_statement` - how Ecto should cache INSERT/UPDATE/DELETE statements.
+      It can either be `:per_schema` (one cache key is used for each schema) or
+      `:per_operation` (one cache key is use for each operation). Note SELECTs
+      use a more complete cache mechanism that considers the query itself.
     * `:connect_timeout` - The timeout for establishing new connections (default: 5000)
     * `:prepare` - How to prepare queries, either `:named` to use named queries
       or `:unnamed` to force unnamed queries (default: `:named`)
diff --git a/lib/ecto/adapters/sql.ex b/lib/ecto/adapters/sql.ex
index 4e42f8d3..ad1537eb 100644
--- a/lib/ecto/adapters/sql.ex
+++ b/lib/ecto/adapters/sql.ex
@@ -453,9 +453,10 @@ defmodule Ecto.Adapters.SQL do
     telemetry_prefix = Keyword.fetch!(config, :telemetry_prefix)
     telemetry = {config[:repo], log, telemetry_prefix ++ [:query]}
 
+    cache_statement = Keyword.get(config, :cache_statement, :per_schema)
     config = adapter_config(config)
     opts = Keyword.take(config, @pool_opts)
-    meta = %{telemetry: telemetry, sql: connection, opts: opts}
+    meta = %{telemetry: telemetry, sql: connection, opts: opts, cache_statement: cache_statement}
     {:ok, connection.child_spec(config), meta}
   end
 
@@ -489,6 +490,12 @@ defmodule Ecto.Adapters.SQL do
 
   ## Query
 
+  defp cache_statement(%{cache_statement: :per_schema}, operation, source),
+    do: "ecto_#{operation}_#{source}"
+
+  defp cache_statement(%{cache_statement: :per_operation}, operation, _source),
+    do: "ecto_#{operation}"
+
   @doc false
   def insert_all(adapter_meta, schema_meta, conn, header, rows, on_conflict, returning, opts) do
     %{source: source, prefix: prefix} = schema_meta
@@ -496,8 +503,7 @@ defmodule Ecto.Adapters.SQL do
     {rows, params} = unzip_inserts(header, rows)
     sql = conn.insert(prefix, source, header, rows, on_conflict, returning)
 
-    cache_statement = "ecto_insert_all_#{source}"
-    opts = [{:cache_statement, cache_statement} | opts]
+    opts = [{:cache_statement, cache_statement(adapter_meta, "insert_all", source)} | opts]
 
     %{num_rows: num, rows: rows} =
       query!(adapter_meta, sql, Enum.reverse(params) ++ conflict_params, opts)
@@ -626,7 +632,7 @@ defmodule Ecto.Adapters.SQL do
 
   @doc false
   def struct(adapter_meta, conn, sql, operation, source, params, values, on_conflict, returning, opts) do
-    cache_statement = "ecto_#{operation}_#{source}"
+    cache_statement = cache_statement(adapter_meta, operation, source)
 
     case query(adapter_meta, sql, values, [cache_statement: cache_statement] ++ opts) do
       {:ok, %{rows: nil, num_rows: 1}} ->
diff --git a/lib/ecto/adapters/tds.ex b/lib/ecto/adapters/tds.ex
index 235d75e6..4e6d3110 100644
--- a/lib/ecto/adapters/tds.ex
+++ b/lib/ecto/adapters/tds.ex
@@ -18,6 +18,13 @@ defmodule Ecto.Adapters.Tds do
     * `:pool` - The connection pool module, defaults to `DBConnection.ConnectionPool`
     * `:ssl` - Set to true if ssl should be used (default: false)
     * `:ssl_opts` - A list of ssl options, see Erlang's `ssl` docs
+    * `:cache_statement` - how Ecto should cache INSERT/UPDATE/DELETE statements.
+      It can either be `:per_schema` (one cache key is used for each schema) or
+      `:per_operation` (one cache key is use for each operation). Note SELECTs
+      use a more complete cache mechanism that considers the query itself.
+    * `:show_sensitive_data_on_connection_error` - show connection data and
+      configuration whenever there is an error attempting to connect to the
+      database
 
   We also recommend developers to consult the `Tds.start_link/1` documentation
   for a complete list of all supported options for driver.