Remove ast-cache flag

Summary:
AST caching should be well tested by now.
We should consider removing `Context.is_query_cached_` member as well as the
implementation and tests for `CypherMainVisitor`.

Reviewers: mislav.bradac, mferencevic, buda

Reviewed By: mislav.bradac

Subscribers: pullbot

Differential Revision: https://phabricator.memgraph.io/D833

config/benchmarking_latency.conf

@@ -32,8 +32,5 @@
 # database recovering is disabled by default
 --snapshot-recover-on-startup=false
 
-# use ast caching
---ast-cache=true
-
 # number of workers
 --num-workers=1

config/benchmarking_throughput.conf

@@ -24,5 +24,3 @@
 # database recovering is disabled by default
 --snapshot-recover-on-startup=false
 
-# use ast caching
---ast-cache=true

config/stress.conf

@@ -24,5 +24,3 @@
 # database recovering is disabled by default
 --snapshot-recover-on-startup=false
 
-# use ast caching
---ast-cache=true

config/testing.conf

@@ -24,5 +24,3 @@
 # database recovering is disabled by default
 --snapshot-recover-on-startup=false
 
-# use ast caching
---ast-cache=true

docs/user_technical/installation.md

@@ -75,7 +75,6 @@ parameters:
  --snapshot-recover-on-startup | bool | false | Recover the database on startup using the last<br/>stored snapshot.
  --query-execution-time-sec | integer | 180 | Maximum allowed query execution time. <br/>Queries exceeding this limit will be aborted. Value of -1 means no limit.
  --memory-warning-threshold | integer | 1024 | Memory warning threshold, in MB. If Memgraph detects there is less available RAM available it will log a warning. Set to 0 to disable.
- --ast-cache | bool | true | Use AST caching.
  --query-plan-cache | bool Cache generated query plans.
  --query-plan-cache-ttl | int | 60 | Time to live for cached query plans, in seconds.
  --query-cost-planner | bool | true | Use the cost-estimating query planner.

src/query/interpreter.cpp

@@ -5,10 +5,6 @@
 #include "query/plan/vertex_count_cache.hpp"
 #include "utils/flag_validation.hpp"
 
-// TODO: Remove this flag. Ast caching can be disabled by setting this flag to
-// false, this is useful for recerating antlr crashes in highly concurrent test.
-// Once antlr bugs are fixed, or real test is written this flag can be removed.
-DEFINE_bool(ast_cache, true, "Use ast caching.");
 DEFINE_bool(query_cost_planner, true,
             "Use the cost-estimating query planner.");
 DEFINE_bool(query_plan_cache, true, "Cache generated query plans");

src/query/interpreter.hpp

@@ -18,8 +18,6 @@
 #include "threading/sync/spinlock.hpp"
 #include "utils/timer.hpp"
 
-// TODO: Remove ast_cache flag and add flag that limits cache size.
-DECLARE_bool(ast_cache);
 DECLARE_bool(query_cost_planner);
 DECLARE_bool(query_plan_cache);
 DECLARE_int32(query_plan_cache_ttl);
@@ -62,15 +60,9 @@ class Interpreter {
   void Interpret(const std::string &query, GraphDbAccessor &db_accessor,
                  Stream &stream,
                  const std::map<std::string, TypedValue> &params) {
-    if (!FLAGS_ast_cache && !params.empty()) {
-      // This is totally fine, since we don't really expect anyone to turn off
-      // the cache.
-      throw utils::NotYetImplemented(
-          "Params not implemented if ast cache is turned off");
-    }
     utils::Timer frontend_timer;
     Context ctx(db_accessor);
-    ctx.is_query_cached_ = FLAGS_ast_cache;
+    ctx.is_query_cached_ = true;
     std::map<std::string, TypedValue> summary;
 
     // query -> stripped query

tests/public_benchmark/ldbc/config/memgraph.conf

@@ -23,8 +23,5 @@
 
 --snapshot-recover-on-startup=true
 
-# use ast caching
---ast-cache=true
-
 # number of workers
 --num-workers=8