国测 vexdb

Mon, 27 Jul 2026 14:19:00 +0800

-- cn: 50000
-- dn1: 50005
-- dn2: 50010

vsql -d postgres -p 50000 -r

SELECT * FROM PG_DIST_NODE;

CREATE TABLE t1(c1 INT, c2 TEXT);
SELECT create_distributed_table('t1', 'c1');
-- 创建8个分片，dn1和dn2，每个dn有4个分片，即4个表，表名为 t1_$oid
SELECT * FROM pg_dist_shard; -- min和max是hash之后的值
SELECT * FROM pg_dist_shard_placement;
SELECT * FROM pg_dist_partition;

INSERT INTO t1 VALUES(1, 'aa'), (3, 'bb'), (7, 'cc'), (10, 'dd');

vsql -d postgres -p 50005 -r
SELECT oid,relname FROM pg_class WHERE relname like '%t1%';

vsql -d postgres -p 50010 -r
SELECT oid,relname FROM pg_class WHERE relname like '%t1%';

# cn
SELECT create_distributed_table('t1', 'c1');
 # --> shard 1 (dn1)
 SELECT worker_apply_shard_ddl_command (12042, 'CREATE TABLE public.t1 (c1 integer, c2 text) WITH (orientation=row, compression=no, fillfactor=80)');
 # dn1
 worker_apply_shard_ddl_command
 ddlnode = ParseTreeNode(sql)
 RelayEventExtendNames(ddlnode, sharid) # 在语法解析树中，把t1名称，修改为t1_$shardid
 ProcessUtilityParseTree
 SELECT worker_apply_shard_ddl_command (12042, 'ALTER TABLE public.t1 OWNER TO shenkun');
 # --> shard 2 (dn2)
 SELECT worker_apply_shard_ddl_command (12043, 'CREATE TABLE public.t1 (c1 integer, c2 text) WITH (orientation=row, compression=no, fillfactor=80)');
 SELECT worker_apply_shard_ddl_command (12043, 'ALTER TABLE public.t1 OWNER TO shenkun');
 # --> shared 3 (dn1)
 ...
 # --> 一共8个分片，每个分片2条SQL！

# cn
INSERT INTO t1 VALUES(1,'aa'),(3,'bb'),(7,'cc'),(10,'dd');
 exec_simple_query
 pg_parse_query
 pg_analyze_and_rewrite
 pg_plan_query
 [planner hook] distributed_planner
 CreateDistributedPlan
 CreateModifyPlan
 RouterInsertJob (deferredPruning=true)
 # 返回 CustomScan
 PortalStart
 ExecutorStart
 [DVecExecutorStart] DVecExecutorStart
 BeginCustomScan → DVecBeginScan
 DVecBeginModifyScan
 RegenerateTaskListForInsert
 BuildRoutesForInsert
 FindShardInterval
 ActiveShardPlacementList
 RebuildQueryStrings
 DeparseTaskQuery
 AppendShardIdToName # 生成改名后SQL
 PortalRun
 ExecutorRun
 [ExecutorRun_hook] DVecExecutorRun
 ExecCustomScan
 DVecExecScan
 AdaptiveExecutor
 RunDistributedExecution
 ...
 SendRemoteCommand
 StartRemoteTransactionBegin
 BeginTransactiionCommand # 生成：BEGIN ISOLATION LEVEL READ COMMITTED;
 AssignDistributedTransactionIdCommand # 生成：SELECT assign_distributed_transaction_id(0,20,'...');
 SendRemoteCommand # 一次发送2条事务SQL
 SendRemoteCommand
 PQsendQuery # INTO t1_$shardid ..
 CoordinatedRemoteTransactionsPrepare
 ..
 SendRemoteCommand # 发送 REPARE TRANSACTION ..
 SendRemoteCommand # 发送 COMMIT PREPARED ..
 # --> shard 1 (dn1)
 BEGIN ISOLATION LEVEL READ COMMITTED;
 SELECT assign_distributed_transaction_id(0,20,'...');
 INSERT INTO public.t1_12042 AS dvec_table_alias (c1, c2) VALUES (1,'aa'::text)
 REPARE TRANSACTION 'dvecx_...';
 COMMIT PREPARED 'dvecx_...';
 # 执行分布式事务
 INSERT INTO public.t1_12042 AS dvec_table_alias (c1, c2) VALUES (1,'aa'::text)
 # --> shard 2 (dn2)
 INSERT INTO public.t1_12043 AS dvec_table_alias (c1, c2) VALUES (10,'dd'::text)
 # --> shared 3 (d1)
 ...
 # --> 一共8个分片，其中4个分片，各收到1条INSERT语句
 # 多行在同一分片，INSERT语句合并

# cn
SELECT * FROM t1 WHERE c1 > 10;
 exec_simple_query
 pg_parse_query
 pg_analyze_and_rewrite
 pg_plan_query
 [planner hook] distributed_planner
 CreateDistributedPlan
 GetRouterPlanType
 (一造 multi-shard fan-out(非 router 计划))
 MultiLogicalPlanCreate (logical planner:建逻辑计划)
 CreatePhysicalDistributedPlan (physical planner)
 ├─ 为命中的每个分片建一个 Task(本表 8 个分片 → 8 个 Task)
 UpdateTaskQueryString
 DeparseTaskQuery
 deparse_shard_query
 AppendShardIdToName # t1 → t1_<shardId>
 # SELECT * + c1,c2 ; WHERE c1>10 → (c1 OPERATOR(pg_catalog.>) 10)
 # 包成 CustomScan 返回
 PortalStart
 ExecutorStart
 [DVecExecutorStart] DVecExecutorStart
 BeginCustomScan → DVecBeginScan
 PortalRun
 ExecutorRun
 [ExecutorRun_hook] DVecExecutorRun
 ExecCustomScan
 DVecExecScan
 AdaptiveExecutor
 RunDistributedExecution
 AssignTasksToConnectionsOrWorkerPool # 8 个 Task 分给 DN1/DN2 的连接
 ConnectionStateMachine
 StartRemoteTransactionBegin
 *发送: BEGIN + assign(每条 DN 连接首次用,只发一次)
 BeginTransactionCommand
 # 生成: BEGIN TRANSACTION ISOLATION LEVEL READ COMMITTED
 AssignDistributedTransactionIdCommand
 # 生成: SELECT assign_distributed_transaction_id(...)
 SendRemoteCommand → PQsendQuery
 *两条合并成一条发出
 # 发送: SELECT c1,c2 FROM t1_<shardId> WHERE (c1>10)
 # DN1 上 4 条 (12042/12044/12046/12048), DN2 上 4 条
 (COMMIT)
 RemoteTransactionCommit
 SendRemoteCommand → PQsendQuery
 # 只读 → 普通 COMMIT(无 PREPARE/COMMIT PREPARED,无 2PC)
 # COMMIT

 # --> shard 1 (dn1)
 SELECT c1, c2 FROM public.t1_12042 t1 WHERE (c2 OPERATOR(pg_catalog.>) 'cc'::text)

SELECT * FROM t1 WHERE c2 > 'cc';

密态：
 cn
 CREATE TABLE t1 (c1 ..)
 INSERT INTO t1 VALUES (..)
 SELECT c1,c2 FROM t1 WHERE ..
 dn
 CREATE TABLE t1_$shardid (c1 ..)
 INSERT INTO t1_$shardid VALUES (..) # values的值不变
 SELECT c1,c2 FROM t1_$shardid WHERE .. # WHERE子句不变

e100

Tue, 29 Jul 2025 18:14:00 +0800

./configure --prefix=$PG_HOME --enable_debug --with-openssl --enable-cassert

make -sj 6 && make install

alias pmake='make -sj 6 && make install -sj'
alias pinit='rm -rf $PG_HOME/data && initdb -D $PG_HOME/data'
alias pstart='pg_ctl start -D $PG_HOME/data -l logfile'
alias pstop='pg_ctl stop -D $PG_HOME/data -l logfile'

jdbc

Thu, 24 Jul 2025 19:03:00 +0800

1 使用JDBC的流程

准备java环境
准备jdbc驱动
编写java代码
执行java代码

2 使用JDBC

2.1 准备java环境

安装java工具包

sudo yum install -y java-1.8.0-openjdk java-1.8.0-openjdk-devel

验证java安装成功

java -version
# openjdk version "1.8.0_382" : 8表示java 8

执行java demo

# 编写代码
echo '
public class Demo {
 public static void main(String[] args) {
 System.out.println("Hello World");
 }
}
' >> Demo.java
# 编译代码
javac Demo.java
# 执行
java Demo

2.2 准备jdbc驱动

touch jdbc
cd jdbc
mkdir jars
cd jars
wget https://jdbc.postgresql.org/download/postgresql-42.7.7.jar

目录架构：
|-- jdbc
 |-- jars
 |-- postgresql-42.7.7.jar

https://polydistortion.net/bc/index.html

数据库 on Kernel Notes

国测 vexdb

e100

jdbc

1 使用JDBC的流程

2 使用JDBC

2.1 准备java环境

2.2 准备jdbc驱动