1. 介绍
PostgreSQL提供了一个copy命令的便利数据加载工具，copy命令源于PostgreSQL数据库，copy命令支持文件与表之间的数据加载和表对文件的数据卸载。pg_bulkload是一种用于PostgreSQL的高速数据加载工具，相比copy命令。最大的优势就是速度。优势在让我们跳过shared buffer,wal buffer。直接写文件。pg_bulkload的direct模式就是这种思路来实现的，它还包含了数据恢复功能，即导入失败的话，需要恢复。
2. pg_bulkload架构图
pg_bulkload主要包括两个模块：reader和writer。reader负责读取文件、解析tuple，writer负责把解析出的tuple写入输出源中。pg_bulkload最初的版本功能很简单，只是加载数据。3.1版本增加了数据过滤的功能。
3. pg_bulkload安装
[root@Postgres201 ~]# unzip pg_bulkload-VERSION3_1_10.zip [root@Postgres201 ~]# cd pg_bulkload-VERSION3_1_10 [root@Postgres201 pg_bulkload-VERSION3_1_10]# make [root@Postgres201 pg_bulkload-VERSION3_1_10]# make install
安装完成；要使用它需要建extension
[postgres@Postgres201 ~]$ psql lottu lottu psql (9.6.0) Type "help" for help. lottu=# create extension pg_bulkload; CREATE EXTENSION
4. pg_bulkload参数
[postgres@Postgres201 ~]$ pg_bulkload --help pg_bulkload is a bulk data loading tool for PostgreSQL Usage: Dataload: pg_bulkload [dataload options] control_file_path Recovery: pg_bulkload -r [-D DATADIR] Dataload options: -i, --input=INPUT INPUT path or function -O, --output=OUTPUT OUTPUT path or table -l, --logfile=LOGFILE LOGFILE path -P, --parse-badfile=* PARSE_BADFILE path -u, --duplicate-badfile=* DUPLICATE_BADFILE path -o, --option="key=val" additional option Recovery options: -r, --recovery execute recovery -D, --pgdata=DATADIR database directory Connection options: -d, --dbname=DBNAME database to connect -h, --host=HOSTNAME database server host or socket directory -p, --port=PORT database server port -U, --username=USERNAME user name to connect as -w, --no-password never prompt for password -W, --password force password prompt Generic options: -e, --echo echo queries -E, --elevel=LEVEL set output message level --help show this help, then exit --version output version information, then exit
5. pg_bulkload的使用
创建测试表tbl_lottu和测试文件tbl_lottu_output.txt
[postgres@Postgres201 ~]$ psql lottu lottu psql (9.6.0) Type "help" for help. lottu=# create table tbl_lottu(id int,name text); CREATE TABLE [postgres@Postgres201 ~]$ seq 100000| awk '{print $0"|lottu"}' > tbl_lottu_output.txt
1.不使用控制文件使用参数
[postgres@Postgres201 ~]$ pg_bulkload -i /home/postgres/tbl_lottu_output.txt -O tbl_lottu -l /home/postgres/tbl_lottu_output.log -P /home/postgres/tbl_lottu_bad.txt -o "TYPE=CSV" -o "DELIMITER=|" -d lottu -U lottu NOTICE: BULK LOAD START NOTICE: BULK LOAD END 0 Rows skipped. 100000 Rows successfully loaded. 0 Rows not loaded due to parse errors. 0 Rows not loaded due to duplicate errors. 0 Rows replaced with new rows. [postgres@Postgres201 ~]$ cat tbl_lottu_output.log pg_bulkload 3.1.9 on 2018-07-12 13:37:18.326685 08 INPUT = /home/postgres/tbl_lottu_output.txt PARSE_BADFILE = /home/postgres/tbl_lottu_bad.txt LOGFILE = /home/postgres/tbl_lottu_output.log LIMIT = INFINITE PARSE_ERRORS = 0 CHECK_CONSTRAINTS = NO TYPE = CSV SKIP = 0 DELIMITER = | QUOTE = """ ESCAPE = """ NULL = OUTPUT = lottu.tbl_lottu MULTI_PROCESS = NO VERBOSE = NO WRITER = DIRECT DUPLICATE_BADFILE = /data/postgres/data/pg_bulkload/20180712133718_lottu_lottu_tbl_lottu.dup.csv DUPLICATE_ERRORS = 0 ON_DUPLICATE_KEEP = NEW TRUNCATE = NO 0 Rows skipped. 100000 Rows successfully loaded. 0 Rows not loaded due to parse errors. 0 Rows not loaded due to duplicate errors. 0 Rows replaced with new rows. Run began on 2018-07-12 13:37:18.326685 08 Run ended on 2018-07-12 13:37:18.594494 08 CPU 0.14s/0.07u sec elapsed 0.27 sec
2. 导入之前先清理表数据
[postgres@Postgres201 ~]$ pg_bulkload -i /home/postgres/tbl_lottu_output.txt -O tbl_lottu -l /home/postgres/tbl_lottu_output.log -P /home/postgres/tbl_lottu_bad.txt -o "TYPE=CSV" -o "DELIMITER=|" -o "TRUNCATE=YES" -d lottu -U lottu NOTICE: BULK LOAD START NOTICE: BULK LOAD END 0 Rows skipped. 100000 Rows successfully loaded. 0 Rows not loaded due to parse errors. 0 Rows not loaded due to duplicate errors. 0 Rows replaced with new rows. [postgres@Postgres201 ~]$ psql lottu lottu -c "select count(1) from tbl_lottu;" count -------- 100000 (1 row)
3. 使用控制文件
新建控制文件lottu.ctl
INPUT = /home/postgres/lotu01 PARSE_BADFILE = /home/postgres/tbl_lottu_bad.txt LOGFILE = /home/postgres/tbl_lottu_output.log LIMIT = INFINITE PARSE_ERRORS = 0 CHECK_CONSTRAINTS = NO TYPE = CSV SKIP = 5 DELIMITER = | QUOTE = """ ESCAPE = """ OUTPUT = lottu.tbl_lottu MULTI_PROCESS = NO WRITER = DIRECT DUPLICATE_BADFILE = /home/postgres/tbl_lottu.dup.csv DUPLICATE_ERRORS = 0 ON_DUPLICATE_KEEP = NEW TRUNCATE = YES
使用控制文件进行加载操作
pg_bulkload /home/postgres/lottu.ctl -d lottu -U lottu [postgres@Postgres201 ~]$ pg_bulkload /home/postgres/lottu.ctl -d lottu -U lottu NOTICE: BULK LOAD START NOTICE: BULK LOAD END 5 Rows skipped. 95 Rows successfully loaded. 0 Rows not loaded due to parse errors. 0 Rows not loaded due to duplicate errors. 0 Rows replaced with new rows.
6. 总结
pg_bulkload是一种用于PostgreSQL的高速数据加载工具，相比copy命令。最大的优势就是速度。优势在让我们跳过shared buffer,wal buffer。直接写文件。pg_bulkload的direct模式就是这种思路来实现的。不足的是;表字段的顺序要跟导入的文件报错一致。希望后续版本能开发。
