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Merge pull request #377 from qianbin/optimize-logdb
Optimize logdb
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,50 @@ | ||
| // Copyright (c) 2020 The VeChainThor developers | ||
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| // Distributed under the GNU Lesser General Public License v3.0 software license, see the accompanying | ||
| // file LICENSE or <https://www.gnu.org/licenses/lgpl-3.0.html> | ||
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| package logdb | ||
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| import ( | ||
| "database/sql" | ||
| "sync" | ||
| ) | ||
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| // to cache prepared sql statement, which maps query string to stmt. | ||
| type stmtCache struct { | ||
| db *sql.DB | ||
| m sync.Map | ||
| } | ||
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| func newStmtCache(db *sql.DB) *stmtCache { | ||
| return &stmtCache{db: db} | ||
| } | ||
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| func (sc *stmtCache) Prepare(query string) (*sql.Stmt, error) { | ||
| cached, _ := sc.m.Load(query) | ||
| if cached == nil { | ||
| stmt, err := sc.db.Prepare(query) | ||
| if err != nil { | ||
| return nil, err | ||
| } | ||
| sc.m.Store(query, stmt) | ||
| cached = stmt | ||
| } | ||
| return cached.(*sql.Stmt), nil | ||
| } | ||
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| func (sc *stmtCache) MustPrepare(query string) *sql.Stmt { | ||
| stmt, err := sc.Prepare(query) | ||
| if err != nil { | ||
| panic(err) | ||
| } | ||
| return stmt | ||
| } | ||
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| func (sc *stmtCache) Clear() { | ||
| sc.m.Range(func(k, v interface{}) bool { | ||
| _ = v.(*sql.Stmt).Close() | ||
| sc.m.Delete(k) | ||
| return true | ||
| }) | ||
| } |