From 77f1b7d236dba6b1c859bb428ef32d118ec372e6 Mon Sep 17 00:00:00 2001 From: Mike Bayer Date: Mon, 25 May 2020 22:36:44 -0400 Subject: callcount reductions and refinement for cached queries This commit includes that we've removed the "_orm_query" attribute from compile state as well as query context. The attribute created reference cycles and also added method call overhead. As part of this change, the interface for ORMExecuteState changes a bit, as well as the interface for the horizontal sharding extension which now deprecates the "query_chooser" callable in favor of "execute_chooser", which receives the contextual object. This will also work more nicely when we implement the new execution path for bulk updates and deletes. Pre-merge execution options for statement, connection, arguments all up front in Connection. that way they can be passed to the before_execute / after_execute events, and the ExecutionContext doesn't have to merge as second time. Core execute is pretty close to 1.3 now. baked wasn't using the new one()/first()/one_or_none() methods, fixed that. Convert non-buffered cursor strategy to be a stateless singleton. inline all the paths by which the strategy gets chosen, oracle and SQL Server dialects make use of the already-invoked post_exec() hook to establish the alternate strategies, and this is actually much nicer than it was before. Add caching to mapper instance processor for getters. Identified a reference cycle per query that was showing up as a lot of gc cleanup, fixed that. After all that, performance not budging much. Even test_baked_query now runs with significantly fewer function calls than 1.3, still 40% slower. Basically something about the new patterns just makes this slower and while I've walked a whole bunch of them back, it hardly makes a dent. that said, the performance issues are relatively small, in the 20-40% time increase range, and the new caching feature does provide for regular ORM and Core queries that are cached, and they are faster than non-cached. Change-Id: I7b0b0d8ca550c05f79e82f75cd8eff0bbfade053 --- lib/sqlalchemy/sql/selectable.py | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) (limited to 'lib/sqlalchemy/sql/selectable.py') diff --git a/lib/sqlalchemy/sql/selectable.py b/lib/sqlalchemy/sql/selectable.py index 008959aec..170e016a5 100644 --- a/lib/sqlalchemy/sql/selectable.py +++ b/lib/sqlalchemy/sql/selectable.py @@ -3428,7 +3428,14 @@ class DeprecatedSelectGenerations(object): @CompileState.plugin_for("default", "select") -class SelectState(CompileState): +class SelectState(util.MemoizedSlots, CompileState): + __slots__ = ( + "from_clauses", + "froms", + "columns_plus_names", + "_label_resolve_dict", + ) + class default_select_compile_options(CacheableOptions): _cache_key_traversal = [] @@ -3547,8 +3554,7 @@ class SelectState(CompileState): return froms - @util.memoized_property - def _label_resolve_dict(self): + def _memoized_attr__label_resolve_dict(self): with_cols = dict( (c._resolve_label or c._label or c.key, c) for c in _select_iterables(self.statement._raw_columns) -- cgit v1.2.1