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ALTER TABLE

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Aikesheng Open Source Community
Aikesheng Open Source Community
Jan 30, 2024 · Databases

Troubleshooting VARCHAR Column Expansion Issues with MySQL Online DDL

This article analyzes why ALTER TABLE operations that extend VARCHAR columns sometimes fail in MySQL, explains the underlying Online DDL constraints, presents several real‑world problems such as default‑value handling, indexed columns, and hidden table‑rebuild quirks, and offers practical solutions for each case.

ALTER TABLEDatabase AdministrationMySQL
0 likes · 17 min read
Troubleshooting VARCHAR Column Expansion Issues with MySQL Online DDL
Aikesheng Open Source Community
Aikesheng Open Source Community
Aug 11, 2022 · Databases

Exploring MySQL 8.0.29 Instant ADD/DROP COLUMN Feature and Its Impact on Online DDL

This article demonstrates how MySQL 8.0.29’s ALGORITHM=INSTANT enables instant column addition, deletion, and row‑size checks at any position in large tables, compares performance with previous versions, and discusses related XtraBackup backup considerations.

ALTER TABLEINSTANTMySQL
0 likes · 9 min read
Exploring MySQL 8.0.29 Instant ADD/DROP COLUMN Feature and Its Impact on Online DDL
Top Architect
Top Architect
Dec 5, 2021 · Databases

Why MySQL Table Size Does Not Decrease After DELETE and How to Reduce It

This article explains why deleting rows in MySQL does not shrink the underlying table file, describes the InnoDB storage mechanics that cause this behavior, and provides practical solutions such as OPTIMIZE TABLE, ALTER TABLE, and Online DDL to reclaim space and avoid table‑locking issues.

ALTER TABLEDELETEDatabase
0 likes · 8 min read
Why MySQL Table Size Does Not Decrease After DELETE and How to Reduce It
Top Architect
Top Architect
Nov 17, 2021 · Databases

Why MySQL Table Size Does Not Decrease After DELETE and How to Reduce It

The article explains why MySQL’s DELETE command does not shrink the physical table file, describes InnoDB’s storage mechanics, and shows how to reclaim space using OPTIMIZE TABLE, ALTER TABLE, and Online DDL options.

ALTER TABLEDELETEDatabase Maintenance
0 likes · 7 min read
Why MySQL Table Size Does Not Decrease After DELETE and How to Reduce It
Top Architect
Top Architect
Jul 19, 2021 · Databases

Why MySQL DELETE Does Not Reduce Table File Size and How to Shrink It

The article explains why deleting rows in MySQL does not shrink the physical table file, describes the underlying InnoDB storage mechanisms, and provides practical methods such as OPTIMIZE TABLE, ALTER TABLE, and Online DDL to reclaim space and reorganize the table.

ALTER TABLEDELETEDatabase Maintenance
0 likes · 7 min read
Why MySQL DELETE Does Not Reduce Table File Size and How to Shrink It
Top Architect
Top Architect
Jun 9, 2021 · Databases

Why MySQL DELETE Does Not Reduce Table Size and How to Shrink It

The article explains why deleting rows in MySQL does not shrink the .ibd file because InnoDB only marks pages as reusable, and shows how to reclaim space using OPTIMIZE TABLE, ALTER TABLE, and Online DDL options.

ALTER TABLEDELETEDatabase Maintenance
0 likes · 7 min read
Why MySQL DELETE Does Not Reduce Table Size and How to Shrink It
Laravel Tech Community
Laravel Tech Community
May 13, 2021 · Databases

Why MySQL Table Size Doesn’t Shrink After DELETE and How to Reduce It

This article explains why deleting rows in MySQL does not decrease the physical table file size, describes the underlying InnoDB storage mechanisms, and shows how to reclaim space using OPTIMIZE TABLE, ALTER TABLE, and Online DDL options.

ALTER TABLEDELETEInnoDB
0 likes · 7 min read
Why MySQL Table Size Doesn’t Shrink After DELETE and How to Reduce It
Aikesheng Open Source Community
Aikesheng Open Source Community
Jul 24, 2020 · Databases

Monitoring ALTER TABLE Progress in MySQL Using Performance Schema

This article demonstrates how to enable MySQL's performance_schema, generate test data, run an ALTER TABLE operation, and continuously query a custom SQL statement to estimate the operation's progress and remaining time, providing practical insight into DDL monitoring.

ALTER TABLEDDL MonitoringMySQL
0 likes · 4 min read
Monitoring ALTER TABLE Progress in MySQL Using Performance Schema
Aikesheng Open Source Community
Aikesheng Open Source Community
Jul 18, 2019 · Databases

Understanding MySQL Metadata Locks and ALTER Table Delays with Foreign Keys

The article explains how MySQL metadata locks, especially SHARED_UPGRADABLE and SHARED_READ_ONLY locks acquired during ALTER TABLE on tables with foreign keys, can cause long wait times under concurrent write transactions, and shows how adjusting the max_write_lock_count variable resolves the issue.

ALTER TABLEForeign KeysMetadata Locks
0 likes · 7 min read
Understanding MySQL Metadata Locks and ALTER Table Delays with Foreign Keys