MonetDB: unlock - use fixed set of locks for table level locking

[Niels Nes]

Changeset: 7936325c9612 for MonetDB
URL: https://dev.monetdb.org/hg/MonetDB?cmd=changeset;node=7936325c9612
Modified Files:
        sql/storage/bat/bat_storage.c
        sql/storage/store.c
Branch: unlock
Log Message:

use fixed set of locks for table level locking


diffs (103 lines):

diff --git a/sql/storage/bat/bat_storage.c b/sql/storage/bat/bat_storage.c
--- a/sql/storage/bat/bat_storage.c
+++ b/sql/storage/bat/bat_storage.c
@@ -15,6 +15,9 @@
 
 static MT_Lock segs_lock = MT_LOCK_INITIALIZER("segs_lock");
 static MT_Lock destroy_lock = MT_LOCK_INITIALIZER("destroy_lock");
+#define NR_TABLE_LOCKS 64
+static MT_Lock table_locks[NR_TABLE_LOCKS]; /* set of locks to protect table 
changes (claim) */
+
 storage *tobe_destroyed_dbat = NULL;
 sql_delta *tobe_destroyed_delta = NULL;
 
@@ -913,6 +916,17 @@ table_claim_space(sql_trans *tr, sql_tab
        return LOG_OK;
 }
 
+void
+lock_table(sqlid id)
+{
+       MT_lock_set(&table_locks[id&(NR_TABLE_LOCKS-1)]);
+}
+
+void
+unlock_table(sqlid id)
+{
+       MT_lock_unset(&table_locks[id&(NR_TABLE_LOCKS-1)]);
+}
 /*
  * Claim cnt slots to store the tuples. The claim_tab should claim storage on 
the level
  * of the global transaction and mark the newly added storage slots unused on 
the global
@@ -929,7 +943,7 @@ claim_tab(sql_trans *tr, sql_table *t, s
                return 0;
 
        /* use (resizeable) array of locks like BBP */
-       store_lock();
+       lock_table(t->base.id);
 
        s = t->data;
        if (isNew(t) || isTempTable(t) || s->cs.cleared) {
@@ -968,11 +982,11 @@ claim_tab(sql_trans *tr, sql_table *t, s
                BAT *ui, *uv;
 
                if (0 && table_claim_space(tr, t, cnt) == LOG_ERR) {
-                       store_unlock();
+                       unlock_table(t->base.id);
                        return LOG_ERR;
                }
                if (cs_real_update_bats(&s->cs, &ui, &uv) == LOG_ERR) {
-                       store_unlock();
+                       unlock_table(t->base.id);
                        return LOG_ERR;
                }
 
@@ -982,7 +996,7 @@ claim_tab(sql_trans *tr, sql_table *t, s
                            BUNappend(uv, &deleted, true) != GDK_SUCCEED) {
                                bat_destroy(ui);
                                bat_destroy(uv);
-                               store_unlock();
+                               unlock_table(t->base.id);
                                return LOG_ERR;
                        }
                }
@@ -997,7 +1011,7 @@ claim_tab(sql_trans *tr, sql_table *t, s
        for(lng i=0; i<(lng)cnt; i++){
                if (BUNappend(b, &deleted, true) != GDK_SUCCEED) {
                        bat_destroy(b);
-                       store_unlock();
+                       unlock_table(t->base.id);
                        return LOG_ERR;
                }
        }
@@ -1006,7 +1020,7 @@ claim_tab(sql_trans *tr, sql_table *t, s
 
        /* inserts only write */
        s->cs.wtime = t->base.atime = t->s->base.atime = tr->atime = tr->wstime;
-       store_unlock();
+       unlock_table(t->base.id);
        return (size_t)slot;
 }
 
@@ -2294,4 +2308,7 @@ bat_storage_init( store_functions *sf)
        sf->gtrans_minmax = (gtrans_update_fptr)&minmax;
 
        sf->cleanup = (cleanup_fptr)&cleanup;
+
+       for(int i=0;i<NR_TABLE_LOCKS;i++)
+               MT_lock_init(&table_locks[i], "table_lock");
 }
diff --git a/sql/storage/store.c b/sql/storage/store.c
--- a/sql/storage/store.c
+++ b/sql/storage/store.c
@@ -21,8 +21,8 @@
 #define CATALOG_VERSION 52300
 int catalog_version = 0;
 
-static MT_Lock bs_lock = MT_LOCK_INITIALIZER("bs_lock");
-static MT_Lock flush_lock = MT_LOCK_INITIALIZER("flush_lock");
+static MT_Lock bs_lock = MT_LOCK_INITIALIZER("bs_lock");               /* 
protect access of the gtrans structure */
+static MT_Lock flush_lock = MT_LOCK_INITIALIZER("flush_lock");         /* 
protect flushing and hot snapshots */ 
 static sqlid store_oid = 0;
 static sqlid prev_oid = 0;
 static size_t new_trans_size = 0;
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