INSERT · k8s原理与实践

[TOC] # INSERT INSERT 算子用于将指定的数据插入数据表，数据来源包括直接指定的值和子查询的结果。 OceanBase 数据库支持的 INSERT 算子包括 INSERT 和 MULTI PARTITION INSERT。 ## INSERT INSERT 算子用于向数据表的单个分区中插入数据。如下例所示，Q1 查询将值 (1, '100') 插入到非分区表 t1 中。其中 1 号算子 EXPRESSION 用来生成常量表达式的值。 ~~~ obclient>CREATE TABLE t1 (c1 INT PRIMARY KEY, c2 VARCHAR2(10)); Query OK, 0 rows affected (0.12 sec) obclient>CREATE TABLE t2 (c1 INT PRIMARY KEY, c2 VARCHAR2(10)) PARTITION BY HASH(c1) PARTITIONS 10; Query OK, 0 rows affected (0.12 sec) obclient>CREATE TABLE t3 (c1 INT PRIMARY KEY, c2 VARCHAR2(10)); Query OK, 0 rows affected (0.12 sec) obclient>CREATE INDEX IDX_t3_c2 ON t3 (c2) PARTITION BY HASH(c2) PARTITIONS 3; Query OK, 0 rows affected (0.12 sec) Q1: obclient>EXPLAIN INSERT INTO t1 VALUES (1, '100')\G; *************************** 1. row *************************** Query Plan: ==================================== |ID|OPERATOR |NAME|EST. ROWS|COST| ------------------------------------ |0 |INSERT | |1 |1 | |1 | EXPRESSION| |1 |1 | ==================================== Outputs & filters: ------------------------------------- 0 - output([__values.C1], [__values.C2]), filter(nil), columns([{T1: ({T1: (T1.C1, T1.C2)})}]), partitions(p0) 1 - output([__values.C1], [__values.C2]), filter(nil) values({1, '100'}) ~~~ 上述示例中，执行计划展示中的 outputs & filters 详细列出了 INSERT 算子的输出信息如下： <table data-tag="table" id="table-zed-f98-qm7" class="table"><colgroup span="1" width="139" data-tag="col" id="col-rqr-e6b-ew2" colwidth="1*" colnum="1" colname="col1" style="width:50%" class="col"></colgroup><colgroup span="1" width="609" data-tag="col" id="col-o3i-e5n-gk9" colwidth="1*" colnum="2" colname="col2" style="width:50%" class="col"></colgroup><thead id="thead-wwx-ffi-19a" class="thead"><tr id="tr-793-oah-z4c"><th id="td-zz2-tjw-5f1"><p id="p-x54-ljf-wbw"><b>信息名称</b></p></th><th id="td-m9t-ckc-mxk"><p id="p-ibj-13u-gif"><b>含义</b></p></th></tr></thead><tbody data-tag="tbody" id="tbody-3s1-4zh-20q" class="tbody"><tr data-tag="tr" id="tr-m45-5vf-ra6" class="tr"><td data-tag="td" id="td-qzt-70v-5uk" class="td"><p id="p-elk-bnq-xal">output</p></td><td data-tag="td" id="td-0eh-z7d-mx5" class="td"><p id="p-jkj-rqi-t0c">该算子输出的表达式。</p></td></tr><tr data-tag="tr" id="tr-pzy-flc-ptc" class="tr"><td data-tag="td" id="td-tvg-dsl-1ul" class="td"><p id="p-byo-04w-m82">filter</p></td><td data-tag="td" id="td-8vw-qm7-c5u" class="td"><p id="p-lo0-si6-sjy">该算子上的过滤条件。</p><p id="p-0kw-a6k-xq6">由于示例中 INSERT 算子没有设置 filter，所以为 nil。</p></td></tr><tr data-tag="tr" id="tr-ue7-qyo-zl2" class="tr"><td data-tag="td" id="td-mhb-y19-xz5" class="td"><p data-tag="p" id="p-ff3-3b8-l5e" class="p">columns</p></td><td data-tag="td" id="td-xy3-m7b-9hn" class="td"><p data-tag="p" id="p-ov1-45n-43l" class="p">插入操作涉及的数据表的列。</p></td></tr><tr data-tag="tr" id="tr-941-4qd-u9t" class="tr"><td data-tag="td" id="td-j3m-lvs-ops" class="td"><p id="p-mio-17g-g3d">partitions</p></td><td data-tag="td" id="td-ezk-ztr-72b" class="td"><p id="p-idj-gxh-ex7">插入操作涉及到的数据表的分区（非分区表可以认为是一个只有一个分区的分区表）。</p></td></tr></tbody></table> 更多 INSERT 算子的示例如下： * Q2 查询将值（2, '200'）、（3, '300'）插入到表 t1 中。 ~~~ Q2: obclient>EXPLAIN INSERT INTO t1 VALUES (2, '200'),(3, '300')\G; *************************** 1. row *************************** Query Plan: ==================================== |ID|OPERATOR |NAME|EST. ROWS|COST| ------------------------------------ |0 |INSERT | |2 |1 | |1 | EXPRESSION| |2 |1 | ==================================== Outputs & filters: ------------------------------------- 0 - output([__values.C1], [__values.C2]), filter(nil), columns([{T1: ({T1: (T1.C1, T1.C2)})}]), partitions(p0) 1 - output([__values.C1], [__values.C2]), filter(nil) values({2, '200'}, {3, '300'}) ~~~ * Q3 查询将子查询`SELECT * FROM t3`的结果插入到表 t1 中。 ~~~ Q3: obclient>EXPLAIN INSERT INTO t1 SELECT * FROM t3\G; *************************** 1. row *************************** Query Plan: ==================================== |0 |INSERT | |100000 |117862| |1 | EXCHANGE IN DISTR | |100000 |104060| |2 | EXCHANGE OUT DISTR| |100000 |75662 | |3 | SUBPLAN SCAN |VIEW1|100000 |75662 | |4 | TABLE SCAN |T3 |100000 |61860 | ================================================ Outputs & filters: ------------------------------------- 0 - output([VIEW1.C1], [VIEW1.C2]), filter(nil), columns([{T1: ({T1: (T1.C1, T1.C2)})}]), partitions(p0) 1 - output([VIEW1.C1], [VIEW1.C2]), filter(nil) 2 - output([VIEW1.C1], [VIEW1.C2]), filter(nil) 3 - output([VIEW1.C1], [VIEW1.C2]), filter(nil), access([VIEW1.C1], [VIEW1.C2]) 4 - output([T3.C1], [T3.C2]), filter(nil), access([T3.C2], [T3.C1]), partitions(p0) ~~~ * Q4 查询将值（1, '100'）插入到分区表 t2 中，通过`partitions`参数可以看出，该值会被插入到 t2 的 p5 分区。 ~~~ Q4: obclient>EXPLAIN INSERT INTO t2 VALUES (1, '100')\G; *************************** 1. row *************************** Query Plan: ==================================== |ID|OPERATOR |NAME|EST. ROWS|COST| ------------------------------------ |0 |INSERT | |1 |1 | |1 | EXPRESSION| |1 |1 | ==================================== Outputs & filters: ------------------------------------- 0 - output([__values.C1], [__values.C2]), filter(nil), columns([{T2: ({T2: (T2.C1, T2.C2)})}]), partitions(p5) 1 - output([__values.C1], [__values.C2]), filter(nil) values({1, '100'}) ~~~ ## MULTI PARTITION INSERT MULTI PARTITION INSERT 算子用于向数据表的多个分区中插入数据。如下例所示，Q5 查询将值（2, '200'）、（3, '300'）插入到分区表 t2 中，通过`partitions`可以看出，这些值会被插入到 t2 的 p0 和 p6 分区。 ~~~ Q5: obclient>EXPLAIN INSERT INTO t2 VALUES (2, '200'),(3, '300')\G; *************************** 1. row *************************** Query Plan: =============================================== |ID|OPERATOR |NAME|EST. ROWS|COST| ----------------------------------------------- |0 |MULTI PARTITION INSERT| |2 |1 | |1 | EXPRESSION | |2 |1 | =============================================== Outputs & filters: ------------------------------------- 0 - output([__values.C1], [__values.C2]), filter(nil), columns([{T2: ({T2: (T2.C1, T2.C2)})}]), partitions(p0, p6) 1 - output([__values.C1], [__values.C2]), filter(nil) values({2, '200'}, {3, '300'}) ~~~ 上述示例的执行计划展示中的 outputs & filters 详细列出了 MULTI PARTITION INSERT 算子的信息，字段的含义与 INSERT 算子相同。更多 MULTI PARTITION INSERT 算子的示例如下： * Q6 查询将子查询`SELECT * FROM t3`的结果插入到分区表 t2 中，因为无法确定子查询的结果集，因此数据可能插入到 t2 的 p0 到 p9 的任何一个分区中。从1 号算子可以看到，这里的`SELECT * FROM t3`会被放在一个子查询中，并将子查询命名为 VIEW1。当 OceanBase 数据库内部改写 SQL 产生了子查询时，会自动为子查询命名，并按照子查询生成的顺序命名为 VIEW1、VIEW2、VIEW3... ~~~ Q6: obclient>EXPLAIN INSERT INTO t2 SELECT * FROM t3\G; *************************** 1. row *************************** Query Plan: ============================================== |ID|OPERATOR |NAME|EST. ROWS|COST| -------------------------------------------------- |0 |MULTI PARTITION INSERT| |100000 |117862| |1 | EXCHANGE IN DISTR | |100000 |104060| |2 | EXCHANGE OUT DISTR | |100000 |75662 | |3 | SUBPLAN SCAN |VIEW1|100000 |75662 | |4 | TABLE SCAN |T3 |100000 |61860 | ================================================== Outputs & filters: ------------------------------------- 0 - output([VIEW1.C1], [VIEW1.C2]), filter(nil), columns([{T2: ({T2: (T2.C1, T2.C2)})}]), partitions(p[0-9]) 1 - output([VIEW1.C1], [VIEW1.C2]), filter(nil) 2 - output([VIEW1.C1], [VIEW1.C2]), filter(nil) 3 - output([VIEW1.C1], [VIEW1.C2]), filter(nil), access([VIEW1.C1], [VIEW1.C2]) 4 - output([T3.C1], [T3.C2]), filter(nil), access([T3.C2], [T3.C1]), partitions(p0) ~~~ * Q7 查询将值（1, '100'）插入到非分区表 t3 中。虽然 t3 本身是一个非分区表，但因为 t3 上存在全局索引 idx\_t3\_c2，因此本次插入也涉及到了多个分区。 ~~~ Q7: obclient>EXPLAIN INSERT INTO t3 VALUES (1, '100')\G; *************************** 1. row *************************** Query Plan: ============================================== |ID|OPERATOR |NAME|EST. ROWS|COST| ----------------------------------------------- |0 |MULTI PARTITION INSERT| |1 |1 | |1 | EXPRESSION | |1 |1 | =============================================== Outputs & filters: ------------------------------------- 0 - output([__values.C1], [__values.C2]), filter(nil), columns([{T3: ({T3: (T3.C1, T3.C2)}, {IDX_T3_C2: (T3.C2, T3.C1)})}]), partitions(p0) 1 - output([__values.C1], [__values.C2]), filter(nil) values({1, '100'}) ~~~