feat: Cache results

.schema/pgdog.schema.json

@@ -31,6 +31,17 @@
         "ban_timeout": 300000,
         "broadcast_address": null,
         "broadcast_port": 6433,
+        "cache": {
+          "backend": "redis",
+          "enabled": false,
+          "max_result_size": 0,
+          "policy": "no_cache",
+          "redis": {
+            "cache_key_prefix": "pgdog:",
+            "url": "redis://localhost:6379"
+          },
+          "ttl": 300
+        },
         "checkout_timeout": 5000,
         "client_connection_recovery": "drop",
         "client_idle_in_transaction_timeout": 9223372036854775807,
@@ -275,6 +286,75 @@
         }
       ]
     },
+    "Cache": {
+      "description": "Cache configuration.",
+      "type": "object",
+      "properties": {
+        "backend": {
+          "description": "Which storage backend to use.\n\n_Default:_ `redis`",
+          "$ref": "#/$defs/CacheBackend",
+          "default": "redis"
+        },
+        "enabled": {
+          "description": "Whether to enable caching.\n\n_Default:_ `false`",
+          "type": "boolean",
+          "default": false
+        },
+        "max_result_size": {
+          "description": "Maximum result size in bytes to cache (0 = unlimited).\n\n_Default:_ `0`",
+          "type": "integer",
+          "format": "uint",
+          "default": 0,
+          "minimum": 0
+        },
+        "policy": {
+          "description": "Cache policy: `no_cache` or `cache`.\n\n_Default:_ `no_cache`",
+          "$ref": "#/$defs/CachePolicy",
+          "default": "no_cache"
+        },
+        "redis": {
+          "description": "Redis backend configuration.\n\nOnly read when `backend = \"redis\"`.",
+          "$ref": "#/$defs/RedisConfig",
+          "default": {
+            "cache_key_prefix": "pgdog:",
+            "url": "redis://localhost:6379"
+          }
+        },
+        "ttl": {
+          "description": "Default TTL in seconds for cached queries.\n\n_Default:_ `300`",
+          "type": "integer",
+          "format": "uint64",
+          "default": 300,
+          "minimum": 0
+        }
+      },
+      "additionalProperties": false
+    },
+    "CacheBackend": {
+      "description": "Cache storage backend discriminator.",
+      "oneOf": [
+        {
+          "description": "Redis backend (default).",
+          "type": "string",
+          "const": "redis"
+        }
+      ]
+    },
+    "CachePolicy": {
+      "description": "Cache policy.",
+      "oneOf": [
+        {
+          "description": "Never cache queries for this database.",
+          "type": "string",
+          "const": "no_cache"
+        },
+        {
+          "description": "Always cache read queries.",
+          "type": "string",
+          "const": "cache"
+        }
+      ]
+    },
     "ConnectionRecovery": {
       "description": "controls if server connections are recovered or dropped if a client abruptly disconnects.\n\nhttps://docs.pgdog.dev/configuration/pgdog.toml/general/#connection_recovery",
       "oneOf": [
@@ -574,6 +654,21 @@
           "maximum": 65535,
           "minimum": 0
         },
+        "cache": {
+          "description": "Redis cache configuration for this database.",
+          "$ref": "#/$defs/Cache",
+          "default": {
+            "backend": "redis",
+            "enabled": false,
+            "max_result_size": 0,
+            "policy": "no_cache",
+            "redis": {
+              "cache_key_prefix": "pgdog:",
+              "url": "redis://localhost:6379"
+            },
+            "ttl": 300
+          }
+        },
         "checkout_timeout": {
           "description": "Maximum amount of time a client is allowed to wait for a connection from the pool.\n\n_Default:_ `5000`\n\nhttps://docs.pgdog.dev/configuration/pgdog.toml/general/#checkout_timeout",
           "type": "integer",
@@ -1441,6 +1536,23 @@
         }
       ]
     },
+    "RedisConfig": {
+      "description": "Redis-specific cache backend configuration.\n\nCorresponds to the `[general.cache.redis]` TOML section.",
+      "type": "object",
+      "properties": {
+        "cache_key_prefix": {
+          "description": "Key prefix prepended to every cache key stored in Redis.\n\n_Default:_ `pgdog:`",
+          "type": "string",
+          "default": "pgdog:"
+        },
+        "url": {
+          "description": "Redis connection URL.\n\n_Default:_ `redis://localhost:6379`",
+          "type": "string",
+          "default": "redis://localhost:6379"
+        }
+      },
+      "additionalProperties": false
+    },
     "ReplicaLag": {
       "description": "Replica lag banning configuration. When a replica's replication lag exceeds the threshold, it is banned from serving read queries.",
       "type": "object",