Prepared statements results fails partition pruning if not PointGet

[mjonss]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

Create a sysbench table

sysbench /opt/homebrew/share/sysbench/select_random_ranges.lua --mysql-host=127.0.0.1 --mysql-port=4000 --mysql-user=root --mysql-db=test --tables=1 --table_size=1000000 prepare

Create a similar table, but partitioned and copy the data from the table created by sysbench and finally rename to sbtest1

create table tpart (id int, k int, c char(120),pad char(60), primary key (id,k) clustered, key (k)) partition by range (k) interval (100000) FIRST PARTITION LESS THAN (200000) LAST PARTITION LESS THAN (10100000);
batch on id limit 1000 insert into tpart select * from sbtest1;
rename table sbtest1 to t, tpart to sbtest1;

Run sysbench_random_ranges, note that sysbench is using prepared statements!

sysbench /opt/homebrew/share/sysbench/select_random_ranges.lua --mysql-host=127.0.0.1 --mysql-port=4000 --mysql-user=root --mysql-db=test --tables=1 --table_size=1000000 --time=30 --threads=64 run

2. What did you expect to see? (Required)

performance/qps/transactions per seconds to be in the same order of magnitude as for non partitioned table, not 1/50 or less QPS.

3. What did you see instead (Required)

QPS of ~500 vs ~24k (of non partitioned table).

4. What is your TiDB version? (Required)

tidb_version(): Release Version: v8.3.0 Edition: Community Git Commit Hash: 1a0c3ac3292fff7742faa0c00a662ccb66ba40db Git Branch: release-8.3 UTC Build Time: 2024-08-23 14:33:35 GoVersion: go1.22.1 Race Enabled: false Check Table Before Drop: false Store: tikv

[mjonss]

With this diff, partitioning pruning work and QPS is even a few percentage higher than the non-partitioned table instead:

diff --git a/pkg/planner/core/rule_partition_processor.go b/pkg/planner/core/rule_partition_processor.go
index 1d9e3a0708..092ed936eb 100644
--- a/pkg/planner/core/rule_partition_processor.go
+++ b/pkg/planner/core/rule_partition_processor.go
@@ -1587,9 +1587,11 @@ func (p *rangePruner) extractDataForPrune(sctx base.PlanContext, expr expression
        // the constExpr may not a really constant when coming here.
        // Suppose the partition expression is 'a + b' and we have a condition 'a = 2',
        // the constExpr is '2 + b' after the replacement which we can't evaluate.
-       if !expression.ConstExprConsiderPlanCache(constExpr, sctx.GetSessionVars().StmtCtx.UseCache()) {
-               return ret, false
-       }
+       /*
+               if !expression.ConstExprConsiderPlanCache(constExpr, sctx.GetSessionVars().StmtCtx.UseCache()) {
+                       return ret, false
+               }
+       */
        c, isNull, err := constExpr.EvalInt(sctx.GetExprCtx().GetEvalCtx(), chunk.Row{})
        if err == nil && !isNull {
                ret.c = c